standard air box clearances, how much cold air really gets to it.

[Davezj]

These pictures are for illustrastion purposes only.
I am not trying to say block off the air with plastercine and channel only cold air to the snorkle.
what i am trying to show is how little the clearance is in the under bonnet area in front of the air box, which is the only area that allows cold air straingt to the box.

what did was put plastercine all round the airbox area and shut the bonnet. this made the shape you see here and the flat top of the plastercine shows where it touched the underside of the bonnet.

my snorkle is a bit cut up with the side flages removed and the top cut back also (not my doing).

see pics below

33832

33833

33834

33835

33836

33837

33838

33839

33840

33841

33842

33843

33844

33845

33846

[Wodjno]

It's less than that Dave /yes

As tou are not showing the Bonnet Stay blocking the gap also ..

And cut the centre tab out of the front grill in this pic /yes

http://www.clubvr4.com/forum/attachment.php?attachmentid=33842&d=1271177970

I have :)

And remove the bonnet stay /yes

Cheers

Wodj

[Davezj]

i am not for one minute suggestion all the air that gets to the snorkel is cold air and it come directly from the little grill bit just above the VR4 badge. just how tight it is under there.

if you look at the height of the side bits just on the down slope of the snorkel you can see there is quite a bit of room in that area, so one would assume that the air entering the snorkel would take the path of least resistance, and would come in from the sides in the form of hot air from the engine bay.

and yes glen the bonnet stay is removed as i have gas struts holding the bonnet up. i have not got to the modification bit yet. i could put the bonnet stay back on to show the full blockage. i will do that tomorrow. and don't get me started on the big anti vibration bit of foam that is on the stay, that sits right in front of the snorkel as well.

[Davezj]

the cold air from the front of the car would also come in from the bonnet catch area, which i have blocked off just to show clearance height.

My real point i suppose, and there is a point, and i am going to get to it, eventually. Is............

there will be a lot of hot air going to the snorkel from under the bonnet, what would be the suggested fixes for this.

glens is noted and is a good one, i would also shave off the right hand side and just leave the mounting point i would also enlarge the grill bars in the bit above the VR4 badge so it went all the way across the right hand side of the grill.
this would be complimented with a larger area of blocking off and channeling of the cold air, with some thick foam tape instead of the plastercine. all the way from the left hand side of the bonnet catch opening in the grill top to roughly where the plastercine is on the right hand side so it was more like a funnel.

33848

33849

[Wodjno]

/Hmmm

The Struts u got where u get them from and what pressure are they.. And is u got a Carbon bonnet or still the Mekkle 1 ?

Cheers

Wodj

PS.. I went 0.2 secs quicker on the 1/4 mile with the Bonnet stay removed /Hmmm

[AlanDITD]

consistently?

[Wodjno]

consistently?


Well i was consistently 0.2 secs slower upto the point i removed it /hmmm

[elnevio]

LOL! /haz

The hot air problem is only a problem when stationary. Once you are moving through the air, the air in the engine bay is being replaced rather quickly by cold air from the front anyway.

[Turbo_Steve]

That's cos the bonnet stay is so heavy, Wodj....try taking the spoiler off! :P

If you really really want a nice, high pressure flow of air into the airbox, the best thing you could do is cut a hole in the bonnet in front of the snorkel.

However - I'm not sure where you've got the idea that hot air is getting in there - if the car is moving forward then there is a high pressure zone at the front of the bonnet which will be forcing air through any gap around the bonnet it can into the engine bay. The only time it'll be breathing warm air is when it's stationary, so I don't really see that as much of an issue.

Also, bear in mind that with a typical flow rate of well over 300cfm at full throttle, in one minute you've pretty much emptied the entire underbonnet space of warm air and are drawing in cold from wherever you can get it. As the car is now moving (after 1 minute at full throttle...fairly quickly! :) ) then theres about 2 billion million squillion square feet a minute of cold air being forced through the front grille, radiators, bonnet gaps, round the headlights etc etc

It's an extreme example, but once you're off a dyno, hot-air-induction is only a problem for about 3 seconds when you pull away from being sat idling for several minutes.

I do reckon you're onto something with the air-path, though - it's hardly ideal!

And the plasticine idea is just pure-fricken-genius: one of those "Why didn't I think of that?" moments. Rep your way for that one!

I guess I need to buy an FRP bonnet and cut a hole in it. I just can't find one I like :(

(edited to add) Damn you Nev!

[stuey]

I often thought the frontal area of intake and route into the snorkel was a bit small...

When you mean the bonnet catch, d'ya mean the whole metal mechanism on the left ?
I've thought before cutting away the upper section of the centre grille in front of the intake would let nice cold air in.. nobody tried this ?

[Wodjno]

I didn't think hot air was getting in!
My thoughts were on amount of airflow...

[Davezj]

I often thought the frontal area of intake and route into the snorkel was a bit small...

When you mean the bonnet catch, d'ya mean the whole metal mechanism on the left ?
I've thought before cutting away the upper section of the centre grille in front of the intake would let nice cold air in.. nobody tried this ?

yes bonnet catch the bit in the middle. i have added some more pics to an earlier post

[elnevio]

I didn't think hot air was getting in!
My thoughts were on amount of airflow...
/yes :iagree:

[Wodjno]

I've thought before cutting away the upper section of the centre grille in front of the intake would let nice cold air in.. nobody tried this ?

I already did /yes

[Davezj]

Well i was consistently 0.2 secs slower upto the point i removed it /hmmm

they were the one carlos got hold of in the group buy for about £40, but i did not pay that much as mine were second hand when i bought them and it is a metal bonnet.

[stuey]

Meant more air in general, cold would be a bonus..!:2thumbsup

[Davezj]

i am not convinced about the hot only being a problem wen stationary, the front of the bonnet to the slam panel is quite well sealed when the bonnet is closed.
i think there is a good chance the air from the radiator which will be hot, will after leaving the back of the radiator will hit the front of the engine and either be push up or down depending on how high it is up the radiator it hits.
When the hot air gets pushed up i think it will hit the bonnet and roll forwards and backwards.
the hot air that rolls forwards will go into a sort of hoizontal vortex and roll straight in the snorkel as this is now sucking for england. This is why i think the inlet of the snorkel needs to be isolated from the rest of the engine bay.

If there was massive, massive amounts of air going in to the engine bay then i am sure after a spirited run out the strut brace and right hand intercooler pipe would not be too hot to touch after pulling over and immediately opening the bonnet. which mine always are, plus other metal bits around the engine bay.

this is just a theory but it is a theory. this theory does however fall down when you look at the intake air temps with evo scan. i don't seem to remember them being particularly high, but are they measured before or after the intercooler? is it measured in the MAF as part of the MASS Air Flow measurement.

[Turbo_Steve]

I didn't think hot air was getting in!
Sorry, didn't mean to infer you did, Wodj, it was general musings in Dave's direction :)


And yes, it WILL be breathing in hot air when stationary. But my point is that the SECOND you're NOT stationary, it's getting cold air, the intercooler is getting cooled and the inlet tract is getting cooled. It'll be picking up just as much heat through radiation as it will breathing in at a standstill.

And, of course, the harder you're accelerating, the faster you're going, and the faster you're going the more cold air you've got, and the higher the airspeed is, which means the faster it cools! (think in terms of sticking your hand out of the window at 30mpg and how cold it gets)

I'm not saying it's ideal - far from it, but in terms of performance limiting design issues with our engines heat ingress is extremely low down on the list. Getting that rear turbo to run cooler is a much bigger deal :D

[Davezj]

don't you want the turbos to run as hot as possible for the exhaust side anyway. but keep that heat away from the compressor side as much as possible.

really there should be a verticla heat sheild that runs down the center of the tubro to do this. to isolate exhaust from compressor. transferwell it would help with localised air heat transfer but obviously not the direct heat transfer through the catridge area of the turbo.



I do get you point about the lots of cold air thing steve and the evo scan logs of inlet air temp is undeniably a true picture of the facts.
bang goes my theory. but that is what a theory it for to pose a posibility or a point and then prove or disprove it. and in the imotal words of yes you guest it, and i don't need to tell you who................

BUSTED!

[bradc]

Lol Steve, I think you mean at 30mph which is a speed all VR-4's are capable of. It seems only some VR-4's are capable of 30mpg :D

I have been thinking for some time that running the airbox as it is with a panel filter inside and then a large pipe leading into the airbox that sucks air up from the foglight area might just be the best bet for those not wanting to cut a hole in their bonnet!

[Turbo_Steve]

It might be, but the potential for hoovering up a puddle at that height is significantly increased, brad!

And yes, 30mph, sorry - all I can think of is mpg at the moment. My fuel bill is the same size as most peoples mortgage payments: they're really shocked when I tell them!


Dave - nothing wrong with a theory at all, and big props to you for even considering all this.

With the turbo, bear in mind that the radiant heat being transferred between the two halves is comparitively microscopic compared to the conduction through the metal middle of the turbo!

Also don't forget that the compressor side itself actually gets hot due to the compression process....it's generally just easier to intercool the charge afterwards.

I'm mainly interested in keeping the whole back of the engine cooler, irrespective of turbo performance. Cooling down the exhaust housing isn't going to make a significant difference in performance terms compared to allowing the engine to run cooler, allowing less fuel and more timing.

You need to be worrying about having a "perfect" exhaust design (which is, at the very least, a seperate exhaust for each turbo with a link pipe midway) long before exhaust housing cooling becomes an issue. That said, you could always wrap the exhaust side in a turbo blanket to keep the heat in.

I'd rather cool the whole lot, and run higher EGTs, though - you're not trying until you melt an exhaust manifold :D

[Davezj]

i had thought about cooling the back of the engine bay down a bit by fitting the 2 motorbike radiator fans (which are quite conpact) to a metal fram suspended off the fire wall and blowing down. the rubber seal is off the back of my engine bay so the fans should draw air in from that region as well as hot air from the top of the engine bay, and blow it across the rear exhaust manifold and turbo and blow it out the bottom of the engine bay and once the air flow has been established by the fans, maybe the draw from under the car with act like the draw on a coal fire when you first get it going with a sheet of news paper above the opening. but maybe that is just wishful thinking.
i think the fans would certainly help with the cooling of the rear.

[Turbo_Steve]

It's a thought, but I don't really think that you'll get enough flow through the back on the bonnet - IMO you'd need have an inlet on top of the bonnet (scoop for preference, but UGLY yuk) or a mesh vent or similar. With a scoop you should get downward +ve flow.........with a vent I couldn't be sure without trying it - I'd imagine that it should draw air upwards as it crosses the bonnet.

My thoughts were in terms of having a wide slot across the rear of the bonnet (about the width of the washer jets) that either dropped downwards, or simply spanned the width with a grille (Mercedes E class bonnet?) The problem here is the negative pressure under the car can make it difficult to establish airflow in this direction.

Alternatively, borrow heavily from subaru (look at the old Legacy single turbos) and have a teeeeeny scoop in the bonnet that directs airflow straight onto the turbo-charger.

This would have the benefit that you could put a fan into the assembly to keep air flowing when stationary.

[Davezj]

hmm, i will have to have a bit more of a think about the turbo cooling.

but i have decided what i am going to do about the air intake, a bit of foam tape and a bit of cutting and all will be done, for the better hopefully.

[fassi1]

I thought I'll refresh this thread.
I was looking at the air intake funnel the other day thinking that I should meassure the cross section of its inlet and outlet.
Inlet cross secton of the funnel is about 4 800 mm2 which is almost identical to the MAF outlet cross section.
Outlet cross section of the funnel is about 6 800 mm2 which is a lot more than its inlet cross section.
I wonder if funnel inlet can be restrictive for the stock induction especially running increased boost and having supportive mods like 3" exhaust and larger intercooler.
Has somebody ever tried to compensate smaller funnel inlet by adding an extra duct before air filter fed somwhere from the fog light area as mantioned by Kenneth

" It is possible that the funnel does impede induction, however I haven't seen that proven and there are many of us with very good power figures who use the OEM airbox setup. It could be more cost effective to cut into the airbox before the panel and add another duct into a cold air position low in the wheel well. An added benefit of keeping the upper funnel is that you wont hydraulic your engine easily. "

in this thread
http://www.clubvr4.com/forum/showthread.php?66272-Cone-filters-%28Again!!%29/page2&highlight=maf+diameter

[exevoowner]

had looked at this for ages and looked at the differance in the pfl and fl grills as in daves pictures i thought about adding some kind of shield to the open section at the front but have not tryed any mods yet
I have seen the ARC airbox runs a open filter so as stated the cold air under the bonnet is not a big issue

[fassi1]

I just wonder if inlet cross section of the funnel was as big as its outlet, would that increase the air flow even if OEM inlet cross section of the funnel is as big as MAF's outlet?

[Davezj]

personally i think the biggest restiction to the air flow is the area between the underside of the bonnet and the slam panel just in front of the the snorkle

see picture 14 in the first post, the one with the key in it. please bear in mind that the the normal bonnet stay with it foam insulation bit that sits directly across this area. blocking it off even more.
take a look at your area infron tof the snorkel.

i think the only way to change this restiction is to cut metal from either the underside of the bonnet or from the slam panel and reform it.

but after all that, i don't know if this area does cause a restriction or not.

you would have to work out the max flow of the turbos, then the cross sectioanal area of the smallest area the air has to flow through. then work out the velocity the air would have to travel at to allow the turbos to flow there max value.

then do a test to see what vacuum level you would have to create to suck that level of air flow through the restriction.


but rather than doing that you could just put a big pipe in place of the snokel and run it down the front of the gear box to get cold air in there.
then run the car and see if makes a difference.
if there is a restriction, then i would assume that the restriction would show up most as the turbos flowed there max air flow value. if there is no difference at this point, you can only assume that you have not removed the biggest restriction in the system. and vice versa if it does make a difference. i say you would have to do the test without any boost control due to the possibility that the only effect you get is a slighly higher ultimate boost level, and with boost control fitted you are pegging the ultimate boost level back already and quite significantly.

now for what the difference is this can only really be seen on a boost gauge. If you do not have a dyno to hand to play on. but you would have to have no boost control used and just allow the turbos to spin up as quickly as they want to and create as much boost as they want. but you will have to do this before and after the snorkel was removed.
i can only assume that the boost gauge will show a quicker response or a higher ultimate boost level. but i don't know what effect will occur. if you still had a boost contorl fitted , it will already be effecting the spool up and the boost pressure achieved, so you probably would not see any difference if there was one.

i can't really think of any other way you could test the effect of removing a potential restiction removal.

[HPRULZ]

http://www.autospeed.com/cms/article.html?&title=RamAir-Revelations&A=110824
interesting article on fitting ram air induction to a VR4 may have some use to you.

Kev

[fassi1]

I guess you don't want to be getting negative pressure (vacuum) just before the exit of the snorkel.
Great article Kev.

[Tam]

Hi Dave,

Very cool thread and questions posed. Could you not try a "by the bum dyno" and just remove your bonnet and see how that feels? Also seen on some bikes with home made ram air by removing a headlight and running the channel forward into the high pressure air before its disturbed by the fairing. With bikes they say that ram air only really starts working above 100mph and the airbox design needs to be of a sufficient size to have enough static air for the engine to draw in. With turbo'd cars i dont know how vital this static air is.... I just remember from when i used to watch the DTM cars when the bonnet was removed from the car all you could see was an airbox.

Marc

[fassi1]

I bought a vacuum gauge, should be with me very soon.
Will try to monitore the pressure somwhere around the outlet of the snorkel and somwhere else
and see if it comes up with something clever.

What I'm thinking to do is cut in the snorkel with min 50mm pipe like demonstrated on the picture and run pipe to the bottom of the bumper fitting its inlet somewhere in high pressure area. 50mm diameter pipe is roughly the difference between inlet and outlet of the snorkel.
Yellow cross would be the location for pressure test. Test can be performed with extra inlet blanked and opened. If there is restriction at the very inlet of the stock snorkel, the test should give positive result.

[HPRULZ]

I bought a vacuum gauge, should be with me very soon.
Will try to monitore the pressure somwhere around the outlet of the snorkel and somwhere else
and see if it comes up with something clever.

What I'm thinking to do is cut in the snorkel with min 50mm pipe like demonstrated on the picture and run pipe to the bottom of the bumper fitting its inlet somewhere in high pressure area. 50mm diameter pipe is roughly the difference between inlet and outlet of the snorkel.
Yellow cross would be the location for pressure test. Test can be performed with extra inlet blanked and opened. If there is restriction at the very inlet of the stock snorkel, the test should give positive result.

If you have a look at some of the other threads on the site I posted there are a lot of pieces of cool information regarding pressure zones and airflow but I liked the main article as it detailed the high and low pressure zones for a VR4. :smart: I shall follow this thread and see how u get on.:thumbsup:

Kev

[fassi1]

It's all very exciting. I've ordered all the bits for additional air ducting, went for slightly bigger diameter 60mm.
Hope this test will give something positive.

[Davezj]

remember also that there are extra holes in the air box for water drainage and for the screw behind the battery. so you might want to removethe air box and block the holes up in there.
te article linked above by kev specifies not to take te air from under the car as this is a source of low pressure, so i know it is more work but you do need to get the extra intake pipe to the front of the car somewhere. to make any difference.

[fassi1]

Thanks for the tips Dave. I didn't mean the right bottom cause liku you said thats negative pressure area.
Will try to fit trumpet right next to the intercooler or where the fog light seats as I don't have em.

[elnevio]

Just be careful of puddles and standing water with low-lying air intakes - water doesn't compress very well!

[swinks]

Just be careful of puddles and standing water with low-lying air intakes - water doesn't compress very well!
But it's costless water injection setup, powah gains are endless! :)

[Davezj]

next on my list tomasz, i have a resovoir and a pump, i just need a injector nozzle/mister.

i am programming my own Arduino based controler as well.

[fassi1]

But it's costless water injection setup, powah gains are endless! :)
Yep that's what I'm expecting, huge power gains /JawDroppi
Not sure if internals will take it. /Hmmm

[fassi1]

www.donaldson.com/en/engine/support/datalibrary/034973.pdf‎

This is interesting. Flared entrance makes big improvement in air flow.

[fassi1]

Trumpet and flexi pipe arrived so managed to get them fitted bu haven't cut in to the snorkel yet, still waitting for other bits.

[Davezj]

chris you might find the grill in front of the trumpet will almost completely distroy the ram effect you are look to create in the setup on the picture.
you might want to do a test with your pressure meter with the grill fitted and not fitted. just to check my thoughts.

[fassi1]

Still waitting for vacuum gauge. I want to test OEM intake (snorkel) without cutting in additional air ducting first so it can be compared to modified intake.
Can do test without mesh as well.

[exevoowner]

I know this sounds silly but is there enough room to enlarge the intake snorkle as looking in krises picture it does not meet the top of air filter box ? Im prob blowing hot air and thinking aloud if i get chance over weekend i will see if therr any way to show you guys what i mean

[Davezj]

Still waitting for vacuum gauge. I want to test OEM intake (snorkel) without cutting in additional air ducting first so it can be compared to modified intake.
Can do test without mesh as well.

sound like the correct plan of attack to me nice to see you are doing the job properly, no properly is not the correct word. Thoroughly is the right word.

[fassi1]

I know this sounds silly but is there enough room to enlarge the intake snorkle as looking in krises picture it does not meet the top of air filter box ? Im prob blowing hot air and thinking aloud if i get chance over weekend i will see if therr any way to show you guys what i mean
Snorkel will remain in its OEM place.
What I'm gonna do is cut a hole out in its right hand wall and some way attache 60mm coupler.
Took me while to find something suitabla for this coupler but I've come across webasto 60mm coupler joiner seen on the picture.
I'm gonna cut it in half and use part with cross to the right of the black line. The idea is to keep the air flowing nicely avoiding sharp bends.
Everything arrived apart from vacuum gauge which is disappointing cause I was hoping for some testing this weekend.

[fassi1]

I had a good chance yesterday to hava a look at air intake entrance on Audi A6 Allroad 2.7bit when servicing lpg system.
I must say it looks much better. It is definitely much better designed than VR4's.
It's located right behind front grill so I guess is located right in high pressure area.

[exevoowner]

Yea looks inpresive but dont think there anyway to make ours the same

[fassi1]

I should have measured it. I really like the design of of it. It definitely helps to drag more air in instead of restricting intake.

[exevoowner]

Did notice on mine today that there are 2 molded peices inside to hold upper part up if its worth removing them also ?

[Davezj]

can't you leave the snorkel as it is and fit the pipe to directly to the air box instead, so you are adding the full extra air from the extra pipe rather than just adding more air to the already small snorkel.

[fassi1]

can't you leave the snorkel as it is and fit the pipe to directly to the air box instead, so you are adding the full extra air from the extra pipe rather than just adding more air to the already small snorkel.
I'm adding the full extra air from the extra pipe, explanation for that is:
Snorkel exit cross section is around 6786 mm2, mid section where new pipe will be attached has the same cross section.
Snorkel entrance cross section is around 4554 mm2, extra pipe cross section is 2462 mm2 so in total 7015 mm2
which means im basicly matching snorkel's exit. By attaching it to the snorkel I can achieve smooth and even airflow in to the airbox.
I wouldn't achieve more by attaching the extra pipe directly to the airbox.

[Davezj]

Fair enough, i just thought it would be worth adding it directly to the air box.

[fassi1]

This is what is gonna look like.
Still waitting for vacuum gauge so haven't fitted it properly yet.

[Davezj]

that looks really good, it is going to be nice bit of fabrication.

[SGHOM]

http://www.clubvr4.com/forum/showthread.php?4600-I-need-more-cold-air-!!&highlight=more+air

[fassi1]

Happy days. Vacuum gauge arrived.
What would be the best way to test it, any specific speed, gear, any ideas?

[Davezj]

does it come with just a tube to attach to the gauge or is an electronic sensor for the pressure.

the electronic sensor will be much easier to test and install.

[fassi1]

It's the one with tube beeing attched to the back of the gauge.
Install wont be a problem, it's just temporary for the test.

[Davezj]

you could try a couple of things, mount gauge on dash, tube out the window then ubder bonnet to the front of the car then stick it at the front of the snorkel then the exit of the snorel in the air box, then down by your extra inlet.
i presume you will have to go out for a drive and get your passenger to check the pressure at different speeds, say 30,40, 50, 60, 70, 80 and see what difference it make.
then go out and do the same drive, and do the speeds and checks again , repeat for each position.

well something like that.

i am not sure if the orientation of the tube will make a difference. normally if air is blown across the end of a tube it will create a lower pressure reagion inside the tube, just like blowing across the top of a bottle, will try and reduce the pressure in the bottle. but if you blow directly at a tube end on, you will increase the pressure of in the tube. so i am not sure what the best scenario is.

i suppose as long as it is oriented in the same direction in each of the tests then it should not cause any adverse effects on your findings. it would only raise or lower the entire set of result but should show the trend.

[fassi1]

I managed to fit vacuum gauge. I only managed to do a quick test, unfortunately the weather doesn't help at all.
Traveling at constant speed 20, 30, 50, 60, 70 mph of the boost (mid load) doesn't affect the pressure.
The only circumstances in which vacuum appears is sudden hard acceleration (boost build up).
I've tried hard acceleration from low speed 20mph and higher speeds 50, 60, 70 beggining from lets say 2800-3000rpm,
as long as I stayed in boost accelerating with foot all the way down there was vacuum the highest noticed 0.1 bar.

[Davezj]

The question we have to ask is what does this tell us.

If there is a partial vacuum being monitored then there must be some kind of restiction in the snorkel at that point.

quick question, did you block up the holes in the bottom of the air box?

this leads me to my next question if you put the tube in the actual air box does it change the reading?

what is the reading if put the tube between the MAF and turbo inlet, just out of interest? i would expect it to be higher than at the snorkel. then the question what happens if remove the panel filter.

[Kenneth]

Are you able to data-log from the ECU at the same time? I don't expect you to be able to watch both at the same time, but am interested in checking out the intake air temps for comparison along with the pressure.

0.1 bar is actually quite a bit of vacuum. Are you also able to test in the pipes just before the turbo inlets? It would be interesting to see what the total vacuum is by the time the turbos are trying to compress the air.


Glad to see you are doing this Chris.

[fassi1]

Yes I can log the data from the ECU, that's not a problem. The best idea probably would be to log the air temp with and without extra ducting at the same time when outside temp is the same for both tests. What I only need is some day light so will have to wait with the test for the weekend.
Another location I can test the vacuum is where stock boost valve dumps the air. I'm using EBC so that's blanked at the moment.
The other location I want to test is stock snerkels entrance just for comparrison with its exit.
I'm open to propositions, there will be more day light available for testing during christmas.
I haven't blocked any holes Dave, snorkel and airbox are completely stock and unmodified.
I want to see what happens when testing other locations with stock intake and with extra ducting.

[ianb]

I suspect that the main restriction in the inlet side is actually the MAF. When my VR4 had a MAP2, calibrated not using the MAF but MAP, so MAF meter was redundant, I replaced the MAF with a custom stainless tube (still for sale!) then I got bad boost cut whenever the air temperature got below about 10C, ie all winter. from 2500 up to 4500 on hard acceleration.The colder it got, the worse it got, ie, the colder it was the denser the air. Ben was unable to dial it out, but reluctant to switch off fuel cut for safety concerns. 221.3 at the wheels(auto) in the summer!!

[Davezj]

Ian did you get rid of the stock inlet pipework and just use 2 separate inlet filters one on each turbo, or just remove the MAF?

[Anderz]

0.1 bar vacuum is actually a lot
As Kenneth said it would be interesting to see the total vacuum at the turbo inlets, the pipes are restrictive especially for the front turbo

Keep up the good work :)

[ianb]

Hi Dave,
No, I just replaced the MAF with a fabricated shaped stainless tube, square hole bolting on to the airtbox, high flow air filter, going to a round section to fit into the standard inlet piping. Their must be a fair bit of restriction in the MAF, look through it! so I suspect a lot of gain just from eliminating it. It may be "the elephant in the room", and other measures may make smaller gains, but are a lot more trouble to do.Get rid of the MAF first, see how you go, and only then start doing the other things.

[fassi1]

MAF is probably another restriction for the intake, it's cross section excluding its internals is 4534 mm2 so almost identical to snorkel's entrance 4554 mm2.
I think it will be beneficial to get rid of pre air filter restriction and try to achieve atmosferic pressure at snorkel's exit at any conditions.
I can only confirm from today's driving that any sudden hard acceleration and boost build up moves gauge's needel in to the vacuum meassured at snorkel's exit.

[Kenneth]

Get rid of the MAF first, see how you go, and only then start doing the other things.

He can easily tell the restriction the MAF produces by testing directly behind the MAF and comparing it to the intake snorkel measurements. Removing the MAF is entirely unnecessary at this stage.
The whole point in this exercise is to get some definite data on what restrictions there are and what parts cause them. Once this is ascertained, it should be fairly obvious where to make modifications for the best benefit.

Chris, is there any way to tell what the peak value was? Do you need someone else in the car to look at the gauge?

I would think that the following measurement points would be ideal

1)Snorkel exit (i.e. your current measurement point)
2)Directly behind the MAF
3)Directly in front of the rear turbo
4)Directly in front of the front turbo

You could do either side of the air filter, but I am not sure that is going to be worth while at this stage, since behind the MAF will take that into account anyway.

Having ascertained that there is roughly 0.1bar drop in pressure at point 1, doing your proposed mod and then re-measuring should give a very good indication of the flow on effect.

[fassi1]

I'm waitting for day light to do a proper testing. At the moment day light doesn't last long and work doesn't allow me to do it during the working days.
This saturday will be perfect day for some testing. From driving in darkness and rain I reckon the pick was 0.1bar but don't need to work hard to get it to 0.045-0.05bar,
25mph 2 gear and foot all the way down and needel dips in to vacuum 0.045-0.05bar.

[fassi1]

Finally managed to do some testing. Looking at the gauge in day light makes big difference :)
I tested 3 points seen on the picture.
Outside temp. 8-10 degC, 1.2 bar of boost, completely stock intake from snorkel to turbos with HKS panel filter.

point 1 - highest 0.056 bar of vacuum
point 2 - highest 0.068 bar of vacuum
point 3 - highest 0.095 bar of vacuum

The highest values were always achieved when accelerating hard beginning from second gear so very low speed up to fifth gear and about 120-130mph
The highest value was always achieved very quickly so already very high at second gear and definitely pick at third gear and remained unchanged throughout forth and fifth as long as I kept foot all the way down :)
The other thing I wanted to test was at what boost gauge's needle starts mooving towards vacuum.
Cruising down the road in fourth or fifth slowly increased the boost and at all 3 points that moment was always at around 0.7bar of boost.

I've used plastic tubing for connection "gauge-testing point" just to avoid any flexing from silicone pipe which I'm not very big fan of.
Keep in mind that tubing was quite long, I've tried to keep it as shoort as possible.
The longer the tubing the lower the reading.

[Davezj]

some interesting results chris.

but the question has to be, is the value recorded significant?

idon't know the answer to this, but i am sure there must be someone that has a good handle on this sort stuff.

[fassi1]

We will get the answer to this question when we get some data from testing with extra ducting I'm gonna add.
I can test the points Kenneth mentioned (just after MAF and just before both turbos) but I don't really want to make extra wholes in my only pipes.
If somebody has some pipes MAF-turbos kicking around and dosn't mind to donate I'm more than happy to test all these points.

[Kenneth]

Those figures tell us that the most restriction between the outside world and post MAF is the snorkel.
It doesn't say anything about the MAF since it isn't directly behind, but we at least know that it is less than 1/3 the total restriction to the point measured.

Really need to find out what is going on just in front of the turbos though, since that is the pressure that the compressor sees.

0.095bar is roughly equivalent to 1.4psi
so if the pressure at the compressor inlet is 1.4psi of vacuum, the turbo needs to run at a pressure ratio of 2.2:1 to provide 1 bar of boost on the compressor outlet.

Another way to look at it is that if you were to bring the compressor inlet pressure up to atmospheric at 5500RPM, and nothing else changed (i.e. no closed loop boost control etc) you would gain 2.8psi of peak pressure on the turbo outlets.
Not sure how much of that would make it to the inlet manifold, but if it all made it then you could be looking at an additional 40hp at the wheels.
Thats without taking into consideration torque gains achievable across the RPM range from about 3000RPM upwards.

So yeah, could be significant.... but only if you can get rid of it.


some interesting results chris.

but the question has to be, is the value recorded significant?

idon't know the answer to this, but i am sure there must be someone that has a good handle on this sort stuff.

[fassi1]

Extra bucting fitted and extra testing point right in front of front turbo,
I can already tell that vacuum in front of front turbo with stock intake is even higher than values above.
Keep an eye on this thread cause it may get interesting.

[fassi1]

Time for the results.
I added extra testing point in front of front turbo (4th point)
Outside temp similar 8-10 degC

point 4 with stock snorkel - highest 0.148 bar ( it proves how bad the stock plastic pipe is, guess rear turbo wouldn't be so bad )

After that attached extra ducting and the results are:

point 1 - didn't see the point of testing it
point 2 - highest 0.017 bar of vacuum
point 3 - highest 0.05 bar of vacuum
point 4 - highest 0.086 bar of vacuum

The diference in vacuum readings is quite big which I was really suprised with.
Still running 1.2 bar of boost so my conclusion is that with extra ducting turbos didn't have to spin as fast as with stock snorkel to create 1.2 bar of boost which is beneficial. Done some logging so will have a look at intake temps.

[fassi1]

Air temps are sligtly lower than with stock snorkel /bananaroc
I have 2 log files but don't know how to upload them.

It doesn't look like the MAF is such a big restriction.
Another restrictive part of intake is front turbo pipe so definitely have to get rid of it.

[Davezj]

very interesting.

i think the rear turbo test would be a useful thing to do. Then you would know if i just the front pipe that causes the main restiction.

the next question is can the MAF sensor be removed and a MAP sensor be fitted to the elbow before the throttle body.
The MAF output is a frequency and the MAP output is a DC Voltage level. so if that DC Level can be converted back to a frequency for the ECU to use could this work.
you would have to add a inlet air temp sensor as well as that is in the MAF as well.
this would allow all the inlet pipework to be removed and big fat pipes to be fitted with high flow filters on the end of each pipe. in some kind of cold air area.

you would have to do someting like this, get a feel for freq vs (rpm & load) then duplicate this signal from the MAP output. i would have thought i could do this using an arduino running some code to drive an output on and off to create a frequency i am assuming it is a square wave output type of frequency.

[fassi1]

I don't really want to make any holes in the rear turbo rubber pipe so as I said above if there is a donor with spare pipe I'm more than happy to test it.
The funy side of this modification is that it only cost me around £30 in parts.
Another thing I'm thinking of is custom made trumpet, entrance for the added ducting which would match with its entrance fog light's hole in the bumper and 60mm round exit to match the aluminium pipe, just like in that 91 Galant VR4, which should help to force even more air in to the pipe.
I think Kenneth will be able to answer your question regarding MAF relocation.

[Davezj]

this is great work you are doing chris, on a very interesting topic.
i will have a look over christmas to see if i have a spare rear turbo hose. i might have one in the shed.
the other place you could try if you feel the urge, is the output of the standard boost solenoid where it enters the inlet pipework, this is a little black tube. This is roughly at the split from front to rear turbo on the inlet pipe work.
It should be relatively easy to access as well, the tube from the gauge might just push on the plastic nipple that is already there.
Just a thought.

[Kenneth]

You are essentially describing the MAP-ECU.

You cannot put it before the throttle body because pressure is independent of air flow. You need to be able to measure how much the engine is consuming rather than how much pressure is there. With the throttle body in the way, you just can't know what is getting to the engine.

The standard MAF should run under pressure. It is sealed and uses hot-wire style measurement inside the measurement chambers so in theory, it should still operate OK. I expect it will require some calibration though.
Last option is to look at a SD conversion for the standard ECU. I did one of these but no one was really interested at the time (after saying they were) so it never went anywhere.

I was looking at doing something with Arduino in the manner you describe (had it all coded up, just needed to set it up in the car), however as soon as the standard ECU became programmable, I chucked it in.
Having this sort of thing outside of the ECU introduces issues because the ECU makes its decisions based on lots of parameters, where you then take just one of them and play with it based on multiple OTHER parameters (some of which the ECU already uses, doubling up their usage in the decision making chain) which puts the ECU in an un-predictable state.

I hope that helps.



the next question is can the MAF sensor be removed and a MAP sensor be fitted to the elbow before the throttle body.
The MAF output is a frequency and the MAP output is a DC Voltage level. so if that DC Level can be converted back to a frequency for the ECU to use could this work.
you would have to add a inlet air temp sensor as well as that is in the MAF as well.
this would allow all the inlet pipework to be removed and big fat pipes to be fitted with high flow filters on the end of each pipe. in some kind of cold air area.

you would have to do someting like this, get a feel for freq vs (rpm & load) then duplicate this signal from the MAP output. i would have thought i could do this using an arduino running some code to drive an output on and off to create a frequency i am assuming it is a square wave output type of frequency.

[Kenneth]

I have the spare, but not really that economical to send it to the UK. Perhaps put a WTB on the forums?
I'll donate cash for it if necessary.

[wintertidenz]

I don't really see the rear turbo pipe as that much of a restriction as it's fairly straight. The front is definitely more restrictive from what I've seen...

[Davezj]

You are essentially describing the MAP-ECU.

You cannot put it before the throttle body because pressure is independent of air flow. You need to be able to measure how much the engine is consuming rather than how much pressure is there. With the throttle body in the way, you just can't know what is getting to the engine.

The standard MAF should run under pressure. It is sealed and uses hot-wire style measurement inside the measurement chambers so in theory, it should still operate OK. I expect it will require some calibration though.
Last option is to look at a SD conversion for the standard ECU. I did one of these but no one was really interested at the time (after saying they were) so it never went anywhere.

I was looking at doing something with Arduino in the manner you describe (had it all coded up, just needed to set it up in the car), however as soon as the standard ECU became programmable, I chucked it in.
Having this sort of thing outside of the ECU introduces issues because the ECU makes its decisions based on lots of parameters, where you then take just one of them and play with it based on multiple OTHER parameters (some of which the ECU already uses, doubling up their usage in the decision making chain) which puts the ECU in an un-predictable state.

I hope that helps.

kenneth can you clarify a couple thing you have stated.
the MAF works on Air Flow and the MAP works on Manifold pressure (which should tell me something about where it should be fitted) , but bear with me.

the MAF only reads the air flow pre throttle body.
i am proposing to imatate the MAF with a MAP , and modify the Map output to be a freq so the ECU thinks it it reading a MAF snesor. so why would i want to fit it in a different location to the MAF.
i am not being funny or odd hear i just want to hear your logic on this.

is it due to the Maf measures flow only when the throttle body is open, and the map sensor (if it fitted in the manifold) only measures pressure when the throttle bossy is open.
have i just answaered my own question.
i think i have.

[c0xxy]

Last option is to look at a SD conversion for the standard ECU. I did one of these but no one was really interested at the time (after saying they were) so it never went anywhere.

how far did you get / what interest is needed?

thanks
ash

[Kenneth]

Hi Dave

The thing to keep in mind is that in a closed system, the air in one end must come out the other. As the MAF reads volume, if there is air flowing in, it must be being consumed. The ECU assumes that this is being done by the engine and so makes some calculations based on what it knows the engine is capable of doing and works out a load value. Because it knows the air mass it can also use that to determine how long to keep the injectors open to deliver the correct amount of fuel.
This is why we have issues with VTA BOVs and boost/vacuum leaks. If there is air going somewhere or coming from somewhere other than the MAF, it calculates the load and fuel delivery wrong.

Pressure on the other hand can be had with very little flow, so long as one end is blocked (throttle plate closed). Or, you could have lots of flow but little pressure when the throttle plate is open. So pressure is meaningless if it is read before the throttle plate.

In the manifold however, the exit is through the engine. If you know the engine RPM and the Volumetric Efficiency (VE) you can determine how much the engine is consuming for a particular pressure and calculate how much fuel is needed.

You could put the MAF in the pressure side of the pipe work (google: blow through maf) but OEMs don't seem to do that, probably for reliability/cost reasons.

So as an answer, the MAF will measure air flow. Air flow is regardless of throttle plate being open or closed and so long as the system is sealed, it works well as a direct measure of the air being used by the engine.
Pressure is 1 parameter which, along with a couple of others, can also be used to calculate air consumption, however it can only be accurate when the flow characteristics of the engine are known in relationship to the engine speed.
In theory you could do this pre-throttle body, but you would need to add another dimension (TPS) to the lookups which would use considerably more map space and add tuning complexity and is frankly unnecessary.


kenneth can you clarify a couple thing you have stated.
the MAF works on Air Flow and the MAP works on Manifold pressure (which should tell me something about where it should be fitted) , but bear with me.

the MAF only reads the air flow pre throttle body.
i am proposing to imatate the MAF with a MAP , and modify the Map output to be a freq so the ECU thinks it it reading a MAF snesor. so why would i want to fit it in a different location to the MAF.
i am not being funny or odd hear i just want to hear your logic on this.

is it due to the Maf measures flow only when the throttle body is open, and the map sensor (if it fitted in the manifold) only measures pressure when the throttle bossy is open.
have i just answaered my own question.
i think i have.

[Kenneth]

I got it to the point where someone needs to give it dyno/tuning time to work out the initial VE maps. The code is almost done but it needs the switch from MAF to MAP to work. No point in doing that until someone runs it and with logging etc to find out if the calculations are working.

Of course there is real potential for engine damage if you go and play with this sort of thing, so it requires good know-how and a level of risk which you would need to be comfortable with.


how far did you get / what interest is needed?

thanks
ash

[exevoowner]

Were's @ foxied when you need him

[Davezj]

Hi Dave

The thing to keep in mind is that in a closed system, the air in one end must come out the other. As the MAF reads volume, if there is air flowing in, it must be being consumed. The ECU assumes that this is being done by the engine and so makes some calculations based on what it knows the engine is capable of doing and works out a load value. Because it knows the air mass it can also use that to determine how long to keep the injectors open to deliver the correct amount of fuel.
This is why we have issues with VTA BOVs and boost/vacuum leaks. If there is air going somewhere or coming from somewhere other than the MAF, it calculates the load and fuel delivery wrong.

Pressure on the other hand can be had with very little flow, so long as one end is blocked (throttle plate closed). Or, you could have lots of flow but little pressure when the throttle plate is open. So pressure is meaningless if it is read before the throttle plate.

In the manifold however, the exit is through the engine. If you know the engine RPM and the Volumetric Efficiency (VE) you can determine how much the engine is consuming for a particular pressure and calculate how much fuel is needed.

You could put the MAF in the pressure side of the pipe work (google: blow through maf) but OEMs don't seem to do that, probably for reliability/cost reasons.

So as an answer, the MAF will measure air flow. Air flow is regardless of throttle plate being open or closed and so long as the system is sealed, it works well as a direct measure of the air being used by the engine.
Pressure is 1 parameter which, along with a couple of others, can also be used to calculate air consumption, however it can only be accurate when the flow characteristics of the engine are known in relationship to the engine speed.
In theory you could do this pre-throttle body, but you would need to add another dimension (TPS) to the lookups which would use considerably more map space and add tuning complexity and is frankly unnecessary.

Hi kenneth, thanks for the answer, I was hoping to was going to more of a linear relationship between air flow and pressure, but I see what you mean.
I will have a think about it some more.

[fassi1]

Our stock air box is good enough for high powers but snorkel and its entrance location is rubbish. It must be replaced with bigger volume ducting with entrance in high pressure zone. Basing on front turbo vacuum with stock snorkel running 1.2 bar of boost my ratio was 2.56. Adding extra ducting pressure in front of front turbo increased to 0.946 bar
so with the same ratio (turbo spinning with the same rpm) I could achieve 1.42 bar of boost.
I may try to log the boost curve running 1.2 bar of boost with stock snorkel and added ducting to see if there is difference in boost build up versus rpm.

[fassi1]

I've made some slight mistakes in my yesterdays calculations, it's all cause gauge doesn't read in bar, it reads in inHg.
Gain in preturbo preassure is slightly smaller but still benefitial and shows the trend.
I've corrected previous yesterday's test values.
Running 1.2 bar of boost ratio is 2.58 which with preturbo pressure 0.913bar gives 1.36 bar of boost.
This time calculations are correct. I do apologize.

[c0xxy]

I got it to the point where someone needs to give it dyno/tuning time to work out the initial VE maps. The code is almost done but it needs the switch from MAF to MAP to work. No point in doing that until someone runs it and with logging etc to find out if the calculations are working.

Of course there is real potential for engine damage if you go and play with this sort of thing, so it requires good know-how and a level of risk which you would need to be comfortable with.

is that all one step?
admittedly, my grasp of ecu tuning is... not very existent but if the first step is to install the various sensors and send you the logs, then im more than happy to help.

what would be involved with dyno/tuning to work out the initial maps?

just to add, im still waiting to fit adams cams, and have a spare engine so if anything pops, it'l just force my hand

ash

[Kenneth]

Hi Ash
You need to be at least able to read the following thread, specifically the SD stuff about VE mapping. You can do the VE mapping by just getting a MAP sensor, hooking it up to the spare ADC input and logging. The thread is: http://www.geekmapped.com/forums/showthread.php?t=1945

If you get that far, we are in business. Sorry to not be overly helpful, its just that there is little point in me repeating what has already been discussed elsewhere.
If you get to the point where you have done VE mapping, let me know and we can progress. Probably best to PM me at that point or start a new thread.

[Davezj]

I have a logged (via evoscan) map sensor connected to ecu, so I can plot the map sensor output verses the freq output of MAF sensor, under different load conditions. This would give a conversion table for the freq to dc voltage output. I had forgotten I had the sensor fitted as I only use it for plotting AFR against boost when I do some performance runs, to keep an eye on what is actually going on in in real data.

[c0xxy]

Think its map, iat n rpm that need to be used

[fassi1]

This inlet should work much better :)
May put mesh in front of it.

[fassi1]

Quick review on performance with fitted extra ducting and air inlete. Boost build up is much quicker and it hits desired 1.2 bar very quickly holding it for much longer.
It's hard to drive and look at the EBC display and rev counter at the same time, but in 5th gear at 5000rpm I was still holding 1.2bar.
When going over the power band, boost doesn't fall stupidly low and at 6500rpm I was holding 1.02bar.
The other positive thing is when I stoped and got the bonnet up to check the intake pre air box component's temps at least by touching em, the aluminium pipe was well colder
than my hand all the way up, when left hand side of the stock funnel was already hotter than my hand absorbing heat from the engine and radiator top hose pipe.

[Trotty]

Very impressive. Ill be looking at improving the stock snorkel as I don't see the air box as a restriction. Well executed.

[adaxo]

Well deserved rep given.

[fassi1]

Thanks to ebo06 rear turbbo pipe is comming my way so soon will be able to test vacuum level in front of rear turbo.
Regarding high pressure air intake location for those who have fog lights, there should be enough room for 60mm pipe and trumpet I had at the beginning right next to radiator just above intercooler air outlet. Just seen VR4 with auto gearbox this morning, it could be tricky cause of the auto gearbox pipes.
I bet it's doable, just would have to have a good look around.

[Erni902]

To answer Davezj question 'how much cold air actually gets to the intake' well alot more gets to mine now :) :

http://www.clubvr4.com/forum/showthread.php?70332-Improved-Induction

fassi1: Chris, bonza job mate, been meaning to do this for quite some time now but just been too busy to read up on the theory behind it all. Top Job

[MarkSanne]

You'd think this would be the case Rikki, but are you sure? Have you measured it somehow? Once the car gets to a certain speed, the 'forced' air might simply flow straight over that vent you made in the bonnet. There is no sure way of telling without measuring. Another thing is rain. And yet another is the limited volume that the front (intake) of the snorkel can accept.

[fassi1]

Back to testing.
I managed to test point 5 just befor rear turbo with added air ducting. Surprise the vacuum level is almost identical, mayby tiny tiny tiny bit lower but nothing major which was 0.086 bar of vacuum. That means that running stock VR4 MAF, front turbo plastic pipe is not restrictive at all. Other restrictive part is 2 outlets from Y joiner after MAF which are only 50mm ID.

[Davezj]

Back to testing.
I managed to test point 5 just befor rear turbo with added air ducting. Surprise the vacuum level is almost identical, mayby tiny tiny tiny bit lower but nothing major which was 0.086 bar of vacuum. That means that running stock VR4 MAF, front turbo plastic pipe is not restrictive at all. Other restrictive part is 2 outlets from Y joiner after MAF which are only 50mm ID.

The figure you have quoted here is with you extra ducting in place is it not.

so you are says that the major things that you believe ned to changed is the ducting into te air box and the ducting from the back of the MAF to the 2 turbos. it is the Y pipe that is causing the most restiction as it is going down to 2 x 50mm outlets. these 50mm outlets need to bigger. and of course the pipes to the turbos have to be bigger also

is that about right?

[fassi1]

Yes the figure is with extra ducting so the vacuum level befor both turbos with stock pipes is identical.
MAF's cross section excluding it's internals is 4534mm2.
2 outlets from Y pipe after MAF cross section is 3925mm2.
I guess onece MAF's internals excluded both cross sections will be very similar.
I reckon that there is no point changing pre turbo pipes if both Y outlets are almost the same as MAF.
I was expecting to see a lower vacuum befor rear turbo cause of that funy looking front turbo plastic pipe, but there is no difference, that means there must be a much bigger restriction than the front turbo pipe causes, which must be MAF and 2 Y pipe outlets.

[Davezj]

so i have got it wrong, what you are saying is the snokel of the air box and the MAF is the major restriction.

i wounder if it is possible to fit 2 MAF's and combine the output of them to still give the correct signal information to the ECU, you would only need to use the output from one of the MAF's for the barometric pressure and the inlet air temp, i think as this should not differ from one MAF to the other, the only thing to combine would be the frequency out from the MAF's. this is easier said than done though.
you can't just use a summing amplifier and sum the 2 frequency outputs as they are waveforms and if they are out of phase with each other they could effectively cancel eachother out. they would have the to converted to 2 DC valtages and then added together and then the sum of the voltages could be converted back to a frequency. again this is easier said than done. as you would have to ensure your frequency output is in the same amplitude range as the original MAF output.
i should have a look at some old logging data to see what the MAF output actually is.

[fassi1]

I reckon that the most restrictive are snorkel, MAF and 2 outlets from Y joiner after MAF.
Having snorkel improoved with added ducting the next restriction is MAF and 2 Y outlets.
Before trying any modyfications it would be good to do a quick test. I mean replace MAF with temporary pipe minimum 80mm ID and test vacuum levels before both turbos.
The only question is what's gonna be ECU's reaction when running with external EBC and without MAF. Will the ECU let us do the test?

[Trotty]

Without running a map sensor the car won't run without maf

[Davezj]

i don't think it will work. it will idle ok without the MAF but it will like a dog without the maff plugged in. i seem to remember doing this accidently after messing with the air box.
you can test it for yourself by just unplugging the MAF and going for a drive.

[wintertidenz]

The ECU throws itself into a limp home mode without the MAF. It will run rich as anything and probably won't boost.

Putting two MAFs on there would cause issues, especially if one was receiving slightly less air flow than the other - the engine is still thinking it's receiving less air and compensating to suit.
The best alternative would be to use a GM MAF and the adaptor box to convert the signal, or a MAP sensor via the ECU.

Have you done the MAF mod yet, and if not, maybe do a couple of tests with this? It may change the restriction slightly.

I had a good look at the spare Y pipe I have, and noted that the inside of the pipe also has those ribs on it - these could cause a slight restriction as it disturbs the airflow.

[c0xxy]

i should think it would be possible to remove the working parts of the maf and add them to a larger pipe, not forgetting to add a new honeycomb thing, then rescale the required parts of the rom

[Kenneth]

Chris, have you tested the pressure directly both sides of the MAF to determine its restriction?

Last I recall, you checked in the pipe directly after the intake had been split in 2 (which is after 2 90 degree bends). This doesn't give a good indication of the MAFs restriction level.

If you were going to run 2 MAFs, you would only need to use a micro controller and calculate the frequency (the VKF signal is a 0-5v square wave with 50% duty cycle) of both incoming signals and then output one where the frequency was added.

However that is 100% unnecessary because there is a very simple and very effective alternative (please check that the MAF is truly the restriction first though).
Add a intake pipe in parallel with the MAF. It needs to join back up before the intake air gets split in 2 though.
You then will need to re-scale your MAF in the ECU.

This process is the equivalent of putting the MAF insides into a bigger pipe. Because the MAF only counts a fixed cross section of the air flow, you have just added to the un-metered portion and so it is then just a case of telling the ECU how much.
Note: It is vitally important that this air supply is not variable. If the flow level fluctuates in relation to the MAF flow rate, then you will have issues because your un-metered air is no longer proportional to the metered air.

[fassi1]

It sounds like we are back to testing and to do it properly really have to test vacuum level just after MAF.
I have to speak to ebo06, he has after MAF Y splitter.
If MAF is not restrictive then is just the case of building after MAF Y splitter and individual pre turbo pipes which is doable.

[Trotty]

This is the front turbo feed pipe I made. Sorta pointless as its fed from a 50mm y piece. But wanted to clean up the last bend before turbo.

http://img.tapatalk.com/d/14/01/07/udetuguv.jpg

http://img.tapatalk.com/d/14/01/07/anupu9ub.jpg

[Davezj]

The ECU throws itself into a limp home mode without the MAF. It will run rich as anything and probably won't boost.

Putting two MAFs on there would cause issues, especially if one was receiving slightly less air flow than the other - the engine is still thinking it's receiving less air and compensating to suit.
The best alternative would be to use a GM MAF and the adaptor box to convert the signal, or a MAP sensor via the ECU.

Have you done the MAF mod yet, and if not, maybe do a couple of tests with this? It may change the restriction slightly.

I had a good look at the spare Y pipe I have, and noted that the inside of the pipe also has those ribs on it - these could cause a slight restriction as it disturbs the airflow.

this is why i suggested the possibility of using 2 Mafs and combining the outputs so the ecu see the full air flow and deliver the correct amount of fuel for the volume of air consumed.

[wintertidenz]

Combining the outputs may also cause real issues too - you would have to calculate the total amount of air across each MAF, each reading (multiple times a second), and send it to the ECU before the reading becomes incorrect.

You would need a very fast microprocessor to do this so as not to introduce lag, and once you have spent the time and money constructing one of the circuits, programming, testing etc... you would be better off changing to a MAP sensor.

EDIT: Looks like Kenneth has the answer :)

[fassi1]

This is the front turbo feed pipe I made. Sorta pointless as its fed from a 50mm y piece. But wanted to clean up the last bend before turbo.

http://img.tapatalk.com/d/14/01/07/udetuguv.jpg

http://img.tapatalk.com/d/14/01/07/anupu9ub.jpg

Very nice replacement but like you said it's fed from 50mm Y piece.


How hard is to get MAP working instead of MAF? I have MAP already fitted reading plenum's pressure as a part of lpg system.

[Davezj]

Chris, have you tested the pressure directly both sides of the MAF to determine its restriction?

Last I recall, you checked in the pipe directly after the intake had been split in 2 (which is after 2 90 degree bends). This doesn't give a good indication of the MAFs restriction level.

If you were going to run 2 MAFs, you would only need to use a micro controller and calculate the frequency (the VKF signal is a 0-5v square wave with 50% duty cycle) of both incoming signals and then output one where the frequency was added.

However that is 100% unnecessary because there is a very simple and very effective alternative (please check that the MAF is truly the restriction first though).
Add a intake pipe in parallel with the MAF. It needs to join back up before the intake air gets split in 2 though.
You then will need to re-scale your MAF in the ECU.

This process is the equivalent of putting the MAF insides into a bigger pipe. Because the MAF only counts a fixed cross section of the air flow, you have just added to the un-metered portion and so it is then just a case of telling the ECU how much.
Note: It is vitally important that this air supply is not variable. If the flow level fluctuates in relation to the MAF flow rate, then you will have issues because your un-metered air is no longer proportional to the metered air.

in the case of adding an extra MAF i presume it is not as easy as just reducing the MAF scaleing be 50%, to add the scond MAF?
if it is just a case of reducing the maf scale to 50%, this would be making a massive assumption that both MAF would be flowing exactly the same amount of air to each turbo. they will always be different. but hopefully not to different.
it would be much safer to add both MAF inputs together to get the total air flowed.

the micro controller is not a problem i can try that option. but i was not sure if this would add to much of a delay or not being able to condition the output signal enough to make it a 0.5Vto 4.5V output, as i was reading if a MAF gives a 0V or a full 5V otput the ecu reads this as a failed MAF. but this might just be in certain types of MAF's i am not 100% sure, i would have to do more research on this one.

[wintertidenz]

With the MAF voltage you would want little to no tolerances - even 0.1v would screw up readings enough to cause issues.
I'd say that you would want as little lag as possible - remember that it has to read the readings from two MAFs, add them together, and then output the correct signal - it would be better to have a microprocessor that's faster than you need.

The other main question as well is where are you going to fit two of our MAFs? They are pretty big, and the room in the engine bay is tight as it is without an extra set of piping and an additional MAF.

[Davezj]

i had assumed the only way to do it would be to remove all the factory inlet and start from scratch, one MAF on each turbo inlet, then you have lots of space to put either a single filter of duel filter to a cold air box/intake snokel.

[Kenneth]

You could possibly assume that there was 50% scaling with 2 MAFs, since they should have been calibrated the same, to match the ECU. Still, the conditions might be different (i.e. the place you feed from might have different pressure) in which case you would still need to tweak the scaling. Overall, you might as well have ditched the 2nd MAF and re-scaled properly to begin with.

It is pretty easy to switch an external voltage with a signal transistor. Should be pretty fast too.
Knowing that the MAF is 50% duty cycle, you can calculate the frequency every half wave by timing the change in voltage. As such, you do not add much delay.

The problems are elsewhere, you need to use a large accumulator to allow the output to be smooth over a wide frequency range. For example, if you tried to use a simple timer compare interrupt, the prescalar settings needed to calculate low frequencies cause jumps in frequency which are quite large. So you use an accumulator, calculate and adder value and add to the accumulator based on the output frequency needed. When the accumulator overflows, you switch the output. Due to the large value of the accumulator, error just accumulates over time and works as rounding.

I did all this at least 3 years ago using an arduino but packed it in as soon as the ECU was flashable. It makes absolutely no practical sense to be messing with external electronics if you can provide a solution inside the ECU. If you are comfortable programming micros, you should be able to pick up the disassembly and start working at the ECU.

[swinks]

One more thing which may be overlooked here.
Different lengths of turbo intake pipes are done for purpose. They are balanced with intercooler outlet pipes, that one y-shaped with different leg lengths, so...
- rear turbo has short compressor intake pipe and long intercooler outing
- front turbo has long compressor intake pipe and short intercooler pipe
That is to balance both tubbys work.

[Davezj]

i am relatively happy with my arduino programming it. I have done some control stuff and menu driven stuff form an LCD display.

[fassi1]

Once again big thankts to ebo06 for after MAF Y piece. Finally will be able to test vacuum level just after MAF and compare it to the other tested parts of the intake. I'm really interested if our MAF is actually very restrictive or not.

[Davezj]

you are making great progress so far. keep it up this is a interesting thread.

[fassi1]

Hopefully all this will pay off. I definitely want to put my leggy on rr at some time this year to see what it does.

[fassi1]

Another testing point just after MAF and whole laboratory. What I need now is a bit of spare time and day light to do few runs.

[Trotty]

Well I don't have any figures but this is what I came up with today. 80mm lobster into 2 2.5' bends. It definitely feels torquier. Shame I didn't measure before after Vacuum levels.

http://img.tapatalk.com/d/14/01/14/2umumu2u.jpg

http://img.tapatalk.com/d/14/01/14/tehujygu.jpg

http://img.tapatalk.com/d/14/01/14/a7e3yjeq.jpg

http://img.tapatalk.com/d/14/01/14/puzuge8y.jpg

http://img.tapatalk.com/d/14/01/14/neryhyzy.jpg

http://img.tapatalk.com/d/14/01/14/vudy5y7a.jpg

[fassi1]

Well done mate, looks great and exactly what I'm planning to do but planning to use 90deg. 80mm or 3.5" elbow.

[Trotty]

U will need a very tight radius 80 mm bend as its very tight. This is why I used a lobster. But then have to squash it to the oval shape of the two 2.5' bends. I was barely able to do it with bends nearly had to go to lobsters on the bottom aswell.

[Nick Mann]

So far the best solutions for the potential MAF restriction have to be Kenneths maf bypass pipe or going MAP and running individual intakes to each turbo.

This is a good thread - I'm watching with interest even if I am not posting often! :D

[fassi1]

Yeah its very tricky part to custom build but like always there must be way around it and your idea Daniel is definitely the one to go for.
Can't wait to see what vacuum level I'm gonna get just after MAF.

[John TheAntique]

Hopefully all this will pay off. I definitely want to put my leggy on rr at some time this year to see what it does.

Chris there is a Dyno Dynamics rolling road just around the corner from you in Luton. http://www.evolveautomotive.com/home.php I have used them and they are very good and helpful.

[fassi1]

I've managed to do 1 quick test for point 6. after MAF with added air ducting: full throttle with second gear in to third and full throttle again.
Vacuum went up to 0.037bar. It was only one quick blast but from testting experiance that will stay around this value or get slightly higher.
I have to do few runs to get proper view on it. Ideally I should test vacuum level before MAF to see how restrictive the MAF is cause between point 2. and 6. we have MAF and air filter.

Thanks for the link John.

[Trotty]

After converting that measurement it works out at approx .5 psi drop. That's an extra psi the turbo has to compress for same flow.

[fassi1]

That's only just after MAF. Pre turbos vacuum is higher 0.087 bar with added air ducting pre air box.
Without it pre turbo vacuum is 0.148 bar.

[Trotty]

So 2.7 psi vacuum. Damn. So the turbo has to pump an extra say 6 psi. That's a lot of extra work to compensate for intake losses.

This would definately explain the extra torque I'm feeling since fitting the intake pipes.

[fassi1]

I would recommend to modify snorkel like I did aswell, that improves pre turbo pressure what was prooved by the test earlier in the thread.

[Davezj]

if the MAF does prove to be restictive, i came accross these the other day and thought they were interesting, just have to find one that has the correct MAF in for our cars.

it is not the correct one but you get the idea.
http://www.ebay.co.uk/itm/251299431887?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649

[swinks]

IIRC, stock maf is 83mm.
That's openning ID of rubber Y-piece, then splitted to 2x 63mm ID.
Turbo compressor entry it's only 45mm ID unfortunately.

[Davezj]

i get what you are saying tomasz, as he has used the same pipe from the outlet of the Y to the turbo inlets, so the overall area of the opening has not changed. but he has changed the way the outlet of the MAF get split into the 63mm outlets. Maybe bigger outlet on the Y pipe section would have made a more of a difference.
but that is just a thought.

[exevoowner]

is it hard to change to a map sensor ?

[Trotty]

We don't have map. We have maf.

[Davezj]

We don't have map. We have maf.

i think you have misread the post, nigel is asking (i believe), is it had to change from using a MAF sensor to using a MAP sensor? e.g. is it possible do to a convertion.
in not so many words.

[Trotty]

Ah. Coolio. I'm pretty sure it's just tuning to suit map. Can be done. Just a lot of time on dyno to get right as u have to pretty much start again.

[fassi1]

I'm gonna test vacuum levels just before the MAF and after MAF properly this time to really see if MAF is actully so restrictive.

[Nick Mann]

The easiest way to go map is to buy a map ecu. It will even sit in learning mode when you fit it so it will populate as much of its own table as it can. Then switch it to control mode and remove the maf and do whatever you want with the intake pipework.

[exevoowner]

So its expencive then lol

[ianb]

I sold my MAP2 piggyback ecu with a plug in harness for £100 last year, the going rate when they come up FS, engine worked fine on map, (I removed MAF).
Worth a search for a 2nd hand one I would have thought, I dont think they are car specific.

[Trotty]

Added this today.
http://img.tapatalk.com/d/14/01/18/y6atuquj.jpg

http://img.tapatalk.com/d/14/01/18/6eme2ure.jpg

39 deg c today on dyno, not great for numbers.

http://img.tapatalk.com/d/14/01/18/dumumupe.jpg

And the results are!!!
http://img.tapatalk.com/d/14/01/18/ehetabed.jpg

[Badger_01]

Added this today.

You need a better panel filter :)

An Hks one will be perfect and will add a bit more better airflow

[Trotty]

Haha the paper filters are fine. Power runs were done with snorkel on but bonnet up.

[fassi1]

39 deg c today on dyno, not great for numbers.

And the results are!!!
http://img.tapatalk.com/d/14/01/18/ehetabed.jpg

Very good result. I guess it's whp.
Very little boost drop at high rpm so all your custom work paid off.

[Nick Mann]

Looks like you added a couple of cylinders too!

[adaxo]

:whistle::whistle::whistle::whistle:/GJ
Looks like you added a couple of cylinders too!
But that was 6 gears ago. Now only 6 left :whistle:

[Trotty]

Very good result. I guess it's whp.
Very little boost drop at high rpm so all your custom work paid off.

That's 195.6kilowatts. It was 268awhp something like that. So nearly stock flywheel figure at the wheels. This was a run with a little knock in it.

http://img.tapatalk.com/d/14/01/18/9yhe9ura.jpg

[swinks]

195kW acheived at flywheel vs. stock Mitsi claim of 205kW...
Still 10kW loss ;)

Daniel, read dyno chart properly. Red line is corrected flywheel. Blue line is wheel horse power. ;)

[Trotty]

195kW acheived at flywheel vs. stock Mitsi claim of 205kW...
Still 10kW loss ;)

Daniel, read dyno chart properly. Red line is corrected flywheel. Blue line is wheel horse power. ;)

Sorry to disappoint but red line is 16 psi run and blue line is stock wastegate pressure of 7 psi. Stock power was 135 kw on 7 psi and the 195.6 was at 16 psi.

[fassi1]

Final test results.
1.2 bar of boost set on EBC with added pre air box air ducting and HKS panel filter, stock pre turbos piping.

point 6 just after MAF - highest 0.041 bar of vacuum
point 7 just before MAF - highest 0.025 bar of vacuum

If we put all the vacuum results in order beginning from snorkel it looks like that:
1.2 bar of boost set on EBC with added pre air box air ducting and HKS panel filter, stock pre turbos piping.

1. point 2 just before air box - highest 0.017 bar of vacuum
2. point 7 just before MAF - highest 0.025 bar of vacuum
3. point 6 just after MAF - highest 0.041 bar of vacuum
4. point 3 just after Y (front turbo leg) - highest 0.05 bar of vacuum
5. point 5 just just before rear turbo - highest 0.086 bar of vacuum
6. point 4 just before front turbo - highest 0.086 bar of vacuum

[Nick Mann]

So that's over 260bhp at the wheels? See, we just can't get those numbers in the UK. Vey good result!

[Nick Mann]

Now that is a useful list of results, Chris. Very interesting. So the MAF is a big restriction, and the funnel and airbox could obviously be improved. The pipework to the turbos seems to be too, but how much of that is down to the pipe section reducing and how much is due to the proximity of the turbo?

[Tayhlor VR4]

Sorry I went full retard and had to edit my comment .

[fassi1]

Now that is a useful list of results, Chris. Very interesting. So the MAF is a big restriction, and the funnel and airbox could obviously be improved. The pipework to the turbos seems to be too, but how much of that is down to the pipe section reducing and how much is due to the proximity of the turbo?
Somebody clever who knows the stuff will have to answer this question.
The test itself prooved how massively restrictive the stock snorkel is. That still can be improoved to get the lowest possible vacuum level before air filter.
The other thing is that the highest vacuum numbers were always achieved at low speeds at gears (2,3).
I think stock piping from MAF to the turbos will be restrictive too due its internal surface not beeing smooth.
Complete custom pipework from MAF to both turbos like Tayhlor did should improove air flow which will help to lower pre turbo vacuum.

[exevoowner]

So looks like we need someone to make a batch of after maf pipe work and a kit for snorkel adaptors or maybe a bespoke intake with either maf delete or upgraded maf and ecu tuning were jason when you need him lol
Would it be possible to make the after maf pipe in silicon

[Davezj]

Final test results.
1.2 bar of boost set on EBC with added pre air box air ducting and HKS panel filter, stock pre turbos piping.

point 6 just after MAF - highest 0.041 bar of vacuum
point 7 just before MAF - highest 0.025 bar of vacuum

If we put all the vacuum results in order beginning from snorkel it looks like that:
1.2 bar of boost set on EBC with added pre air box air ducting and HKS panel filter, stock pre turbos piping.

1. point 2 just before air box - highest 0.017 bar of vacuum
2. point 7 just before MAF - highest 0.025 bar of vacuum
3. point 6 just after MAF - highest 0.041 bar of vacuum
4. point 3 just after Y (front turbo leg) - highest 0.05 bar of vacuum
5. point 5 just just before rear turbo - highest 0.086 bar of vacuum
6. point 4 just before front turbo - highest 0.086 bar of vacuum

just thought i would ask chris, but you do not specify in you result, these results are with your modified snorkel which reduces the vacuum numbers through out the inlet pipework.
you specified earlier in the thread that without the modified snorkel you got 0.146 Bar at the front turbo inlet point (point 6).
which is quite a big difference to the 0.086 Bar of the modified setup.

so the point i am making is anyone with an unmodified snorkel has more to gain than the figures above might suggest.

is this correct chris?

[fassi1]

I reckon that there is no point modifying any pipework post MAF having stock snorkel cause it's massively restrictive.
Once snorkel modified further modifications can be applied.
Doing it other way around just doesn't make sense to me.

[Kenneth]

I calculate the MAF restriction as (0.041 - 0.025) * 14.5 = 0.232 psi. I wouldn't call the 0.232psi MAF restriction big.

The more you improve the rest of the system, the more that the MAF will stand out as being the "big" restriction. At the levels measured, a total of 1.25psi of pressure drop, 0.232 from the MAF is not worth worrying about in my opinion.
The reason I wouldn't worry about it is that it is the most difficult part to modify (requires tuning of some sort) for very small gain. The rest of the pipe work can be removed, replaced, modified without having to worry.

[Trotty]

I actually replaced the front turbo feed pipe first and found no real benefit. Did feel a little perkier. I found best results when I removed the snorkel and ran engine bay temps. I then redid the after maf elbow and Y piece. No real gain again until snorkel was removed. Now I have the bottom feed pipe I'm feeling the gain with snorkel attached. Does this make sense?

[fassi1]

I actually replaced the front turbo feed pipe first and found no real benefit. Did feel a little perkier. I found best results when I removed the snorkel and ran engine bay temps. I then redid the after maf elbow and Y piece. No real gain again until snorkel was removed. Now I have the bottom feed pipe I'm feeling the gain with snorkel attached. Does this make sense?
That's exactly what I meant. There is no point playing with pre turbo pipes, post turbo pipes, upgrading throttle body to a bigger one, unless you've increased an air entrance to the air box. Without it you wont benefit from your upgrades.

[Badger_01]

Cold air box with massive pod on it :D

[Erni902]

Havent had a chance to catch up on this thread for a while due to moving etc. have a week off now so will hopefully look at the snorkel entrance tomorrow and try to increase it. fassi1 Chris what is the cross sectional area of the snorkel entrance I should be aiming for?

P.s good research and hats off to you for obtaining some real figures :)

[fassi1]

Havent had a chance to catch up on this thread for a while due to moving etc. have a week off now so will hopefully look at the snorkel entrance tomorrow and try to increase it. fassi1 Chris what is the cross sectional area of the snorkel entrance I should be aiming for?

P.s good research and hats off to you for obtaining some real figures :)

Personally I would go for the biggest possible. Snorkel's exit has cross section 6786 mm2 so ideally you want to have bigger entrance.

[fassi1]

So looks like we need someone to make a batch of after maf pipe work

I could possibly undertake this task depending on how many people is interested.

[exevoowner]

Well i know i would be intrested

[Erni902]

Personally I would go for the biggest possible. Snorkel's exit has cross section 6786 mm2 so ideally you want to have bigger entrance.

Happy days, cheers Chris at least I now know the minimum size. Hopefully hack up my spare snorkel tomorrow afternoon and post some pics up see what you think. Be good if between us we could sort out some way of testing this with the hole in my bonnet aswell to see if and how much it helps but I spose we'll cross that bridge when we come to it.

Thanks again

[elnevio]

You know what you need? You need a box with a fan in it! :deal2:

[Trotty]

I could possibly undertake this task depending on how many people is interested.

I know I have my hands full keeping just the Australian members happy with fabricated stuff. My weekends are taken for the next 6 months at least lol. 18 sets of dumps. 20 sets of ic pipes and I haven't even put intake in a EOI thread yet. Lol

[AKKO]

Trotty just take care of the VIPs I.e. prioritize those that order one of everything hah.

[Erni902]

Took a Stanley blade to the snorkel and you can find the results HERE (http://www.clubvr4.com/forum/showthread.php?70332-Improved-Induction&p=772901#post772901) Upshot is I now have a cross-sectional area of around 8000mm2 at the snorkel entrance. Obviously needs tidying up etc but thats the general principle of what I was trying to acheive.

[fassi1]

Drastic measures but hopefully will make an improvement.

[Davezj]

Drastic measures but hopefully will make an improvement.

chris,
i thought i would ask this here rather than in you EOI thread as this is more of a discussion point.
this Y pipe after the MAF, you are proposing, has the same size inlet and the same size outlet as the original pipe you are repllacing.
which has been pointed out earlier in this thread but seems to have been over looked.
i don't see the advantage of it.
you have done so much work on this topic and backed it up with measurement data, this just seems like a suggestion of what might work by someone with no measurement data to back up the claim, and it has been taken as fact that this works and makes a positive impact on the issue being investigated.

I am not saying this Y pipe does not have the desired affect, and i am not saying it does. All i am saying is there has been no measurement evidence one way or the other.

it may have a slightly better flow from the point of view the air arcs round rather than turning at 90 deg in the original one, but the outlets ports are the same size. 2.5" is the same as 63mm so the outlets can't actually flow anr more air than the original ones. if you made the outlets bigger it might have the desired effect of reducing the vacuum effect at the turbo inlet. but this would require new larger pipes from the Y to the turbo inlets.

this is just my thought on the subject, i just wondered what you or anyone else thinks.

[fassi1]

It is ID which is important and stock Y outlets have ID 50mm when 2.5" 63mm stainless tube has ID min 59mm
and this tube I would run all the way to the turbos with silicone reducers 63mm to 45mm.

[Davezj]

thats interesting, swinks posted up that the ID of the original Y pipe was 63mm.
I presume you are saying this is not true, and you have measured the ID to be 50mm, so you are saying the OD of the orisinal Y pipe is 63mm.
So the wall thickness of the original Y pipe is 13/2 = 6.5mm thick, which i can well believe as i know the outlet has a thick wall.

so you are actually increasing the size of the outlets of the new Y pipe due to the thinner material being used to fabricate the pipe from.
this all sound good.

but is there any reason why you are not going for a larger ID than the one you have chosen.
is it because that is the normal ID the stainless pipe comes in. that diameter.

[Davezj]

chris,
just out of interest which vacuum gauge did you buy, i was thinking of getting one.

[fassi1]

You got me working Dave :)
Some dimenssions below Y splitter, rear turbo pipe and snorkel.
Y exits are 50-51mm ID, Y entrance 80mm.
Rear turbo pipe entrance 51mm ID (WD-40 fits perfectly), exit 42mm ID (30mm socket fits perfectly).
My snorkel's exit has been slightly trimed.

[fassi1]

some more

[fassi1]

I've played bit more with the snorkel and enlarged its entrance. I reckon that snorkel's entrance should be much bigger than its exit.
Test prroved that even with added 60mm pipe to the snorkel there was still some vacuum just at the snorkel's exit, which without 60mm pipe was much bigger. I reckon that we should be trying to force much more air to the air box to minimize vacuum at the snorkel's exit to almost 0.
Next thing I'm thinking to do is to direct the air towards the snorkel's entrance by adding curved screen similar to the curved piece of cardboard on the picture. That may give me some more front downforce too /lol
The only downside of this screen is that it covers very small piece of radiator behind, but I personally not gonna worry about it.
66297662986629966300

[Davezj]

I've played bit more with the snorkel and enlarged its entrance. I reckon that snorkel's entrance should be much bigger than its exit.
Test prroved that even with added 60mm pipe to the snorkel there was still some vacuum just at the snorkel's exit, which without 60mm pipe was much bigger. I reckon that we should be trying to force much more air to the air box to minimize vacuum at the snorkel's exit to almost 0.
Next thing I'm thinking to do is to direct the air towards the snorkel's entrance by adding curved screen similar to the curved piece of cardboard on the picture. That may give me some more front downforce too /lol
The only downside of this screen is that it covers very small piece of radiator behind, but I personally not gonna worry about it.
66297662986629966300

you have some interesting ideas chris.
if you are going down this route, then you will need to remove the top grill section in front of the snorkel, and make sure you are not getting hot are in from the engine bay.
but i am not sure how much difference this will make.
i refer you back to the start of this thread and point out the restiction of the slam panel and the under side of the bonnet. which can be seen in the picture at the start of this thread with the key in it. it does not matter what you cut out of the snorkel or grill this small slot will always be there unless you do some metal bashing on the slam panel.

[fassi1]

I'm aware of all those details and yes thinking about cutting grill's top section out.
All is insulated and seperated from the engine bay like it was originally.
Hopefully will be able to find out in March at Eurospec if my ideas paid off.

[Davezj]

It would be useful to cut the ridge out of the slam panel that sits directly behind where the bonnet prop sits when the bonnet is closed, or at least move it back towards the snorkel by about an inch or two, to give that extra space.

[MarkSanne]

Hmmm.... my mind starts to wonder and combine stuff that coincidental happening to one of my Galants: last week the missus hit a Pruis and now the front is bent (needs a new bumper, new front mount/frame, new grille, new headlights and new bonnet). I've got all parts and will start welding the new front frame in tomorrow evening. This would be a perfect time to cut up the front, lower the mounts for the radiator and lower a piece of the top frame where the fresh air could be tunneled into! Catching my drift here?! Unfortunately, the car that needs word is the V6 N/A so not much use for these mods, but it would be something I'd consider for the VR2 if the results in this topic are getting (even more) confirmed!

[swinks]

Let me offer you some excercise... :P

Do yourself such gizzmo:
66305

1. Put into your mouth mentioned gizzmo end with 10mm hose ending and try to suck as much air you can.
2. Replace blue silicon reducer with even bigger one, lets say, old one 35mm ID for new 45mm ID and do the step #1.
Have you notice any difference? /Hmmm
No?
Because you have effin restriction in 10mm hose nipple ! /duh

66306

And this apply also to the restiction of TD03-7T compressor inlet. Which is 34mm ID:
66307
Which acts like mentioned 10mm black hose fitting nipple in our gizzmo. :d

Like it or not, but stock hosing is not bad. You can do straighten one, but that's all. No real term gians.

[fassi1]

Who knows we may be changing turbo inlets too ???
I'll give you exercise. Fit 4mm nozzle at the entrance of your gizmo with vacuum gauge connected to it and do ur exercise and see if you can get any vacuum reading.

[swinks]

Oh.. I'm sorry I riuned this...
Will apply mentioned sensor in my bottom end, but I'm afraid it may read only boost there :)

Talking seriously. Rule of thumb is to preserve increase (or rather prevent in any decrease) of duct area from turbo compressor inlet to to the beginning of our air intake system. And this is happening up to air intake snorkel entry.

[fassi1]

Are you trying to say that we all wasting our time and no matter what we do we wont achieve any improvement unless we go for bigger turbos???
It kind of sounds like that. I may have misunderstood.

[exevoowner]

I like you idea MarkSanne im going to be fitting a evo rad soon and have some alloy angle to make some brackets with so was thinking of looking at lowering the rad to allow a intake over the top of the rad

[swinks]

Are you trying to say that we all wasting our time and no matter what we do we wont achieve any improvement unless we go for bigger turbos???
It kind of sounds like that. I may have misunderstood.
To some degree... yes. Definitely.
You won't improve turbo compressor performance by this. You will affect though air flow movement making "bigger chamber" by increase ID of ducting hoses prior to compressor, hence this air will heat up quicker and will keep heat longer. Also making steel or other metal ducting you will need to consider any temperature insulation, heat wrap or ceramic coating.

For comparison, you have "big boy" from Evo with 76mm ID intake compressor and MAF housing (identical size to vr4) or air ducting were NEVER consider as restrictive. Just shorter, but that is different coinsideration. ;)

[Trotty]

At the end of the day I felt improvements under foot by just improving intake. It's about removing restriction before turbo inlet. As stated there is upto 4-5 psi drop at compressor side. Dropping this improves turbo efficiency giving cooler inlet temps as the turbo isn't workin as hard to make up for atmospheric losses.

[Nick Mann]

Anything that aids flow will help, as the pressure drop will reduce. How much you gain is a different question. To my mind the biggest issues will be volume increases as you travel towards the turbos, and barriers to flow. The snorkel appears to have a larger exit than entry - that can't be good. The maf and filter are both barriers to flow. Again, the importance of each of these and the gains could be marginal. Without a shadow of a doubt, running a large filter directly on to each turbo and removing everything else is going to have advantages. To my mind any solution that improves must have gains, but if the gains possible are worth spending money on is not so obvious.

[Trotty]

Well I laid down 200kw@all4wheels. Running intake and exhaust mods on 16psi. That said my tuner seems to think the turbos are workin a lot easier. So in theory I should be able to run more boost before exceeding the flow characteristics of the turbo. So my turbos should run out of puff in the 20-22psi range not 18psi like most seem to hit before they just heat the air.
Here is my dyno sheet again. This was 16psi on a 42deg c ambient day

http://img.tapatalk.com/d/14/01/29/yqe8y6e6.jpg

http://img.tapatalk.com/d/14/01/29/u9aqura3.jpg

[fassi1]

All this makes sense Daniel. By increasing air pressure before compressor and having turbo spinning with exactly the same rpm you will achieve higher pressure post compressor.

[Trotty]

As they say, numbers don't lie. With cooler inlet charge u can add more timing and pull fuel as ur not needing the fuel to cool the charge air as much. Meaning better torque, more fuel economy and better throttle response. I'm goin back to the rollers on the 15th feb to see how much more boost it will take before we see high inlet temps. I'm hoping for about 450nmatw and possible 210-220kw. I need to change my engine mount as it was giving false knock on the day. We will be doin back to back testing of the inlet pipes too. .

[Davezj]

The extreme of this topic is,
1. No pipe on the turbo inlet.
2. A pipe of turbo inlet size 2m long.

Which will cause a resticction. The stock set up is somewhere in the middle.
I know it is a bit of an unfair comparison but they are the extremes of the topic.

So is tomasz saying it does not matter how big the pipe is pre turbo, it will not make any difference to the boost pressure or flow made due to the fact that the turbo inlet is smaller than the inlet pipe, and I'll always be the max restriction point.

I can see where he I coming from, from the point of view that yes the turbo inlet is the most restrictive point, but if the turbo can not have access to an unlimited/unrestricted supply of air then it will not make the maximum boost in the most efficient way.
However, if there is not some kind of vacuum (pressure difference) between the turbo inlet and the snorkel inlet, there will be no air movement/no flow of air.
So I suspect there has to be a pressure difference but the size of it is in question.

I don't know if there is some kind of magic best number for this, I have not read anything to suggest this but I would imagine this has all been tested and worked out buy someone else in the world before, it must have.

[Trotty]

The way I see it is that the turbos are still able to outflow the standard inlet pipes, airbox and snorkel. Obviously we can't do anything about the size of the turbo inlet housing. But we can reduce pressure drop before that point.
Totally understand about just running pods on the turbos would be far more efficient. Unfortunately we can only work with what we got. Not every1 is keen for map. So we design options for the masses. That's work in real word situations, only benefit is we are not restricted by manufacturing costs like Mitsubishi and ease of fitment on assembly line and drive by noise requirements. Not to mention its a pipe designed to go around a transmission oil cooler that doesn't exist for manuals. But Mitsubishi restrained by production costs gave us the restricted pipe in the manuals.

[Davezj]

This is a very interesting topic, and I am enjoying all the theories and resonings behind them, also the testing and measurement that has been done to prove or disprove any points.
I am liking it a lot.

[swinks]

Well..., and in all this you forgot about job of hot side. You won't get any significant improvement of turbo efficiency till you not get proper exhaust gas flow to spin a turbo. Simply you don't. And again, you will hit restriction of silly camshaft profiles of 214 degrees with almost no lift, etc.

It's effin turbocharger, which uses exhaust gases, not a bloody electric fan blower called compresor. You want improvement? Do a direct water or methanol mist injection into a compressor wheel. Cheaper, simpler and bigger gains (further reading in 3si and EvolutionM forum).

[Trotty]

Hey swinks. I have already addressed the dumps as a restriction. Refer to pics.
http://img.tapatalk.com/d/14/01/29/9ygepehe.jpg

http://img.tapatalk.com/d/14/01/29/adeny8er.jpg

[Davezj]

Well..., and in all this you forgot about job of hot side. You won't get any significant improvement of turbo efficiency till you not get proper exhaust gas flow to spin a turbo. Simply you don't. And again, you will hit restriction of silly camshaft profiles of 214 degrees with almost no lift, etc.

It's effin turbocharger, which uses exhaust gases, not a bloody electric fan blower called compresor. You want improvement? Do a direct water or methanol mist injection into a compressor wheel. Cheaper, simpler and bigger gains (further reading in 3si and EvolutionM forum).

Is that really the best place to do the water meth injection, directry on to the compressor wheel, I thought it was supposed to be in front of the throttle body.

[Trotty]

If u were to spray water/meth into the compressor I would like to see the results. As the wheel would quickly wear away from the abrasive properties of the water. Throttle is much better for input location. U would also get more heat transfer as the air is much hotter having a better vaporisation effect.

[fassi1]

Tomasz I've upgraded exhaust long time ago and Trotty went even further upgrading dumps.
I completely agree with Trotty. I think that endless comparissons to EVO are pointless because it's completely different set up and turbo is a lot more efficient and powerfull so it's not rocket science that it can generate a lot higher boost from the same hosing ID.

I've done few more pictures yesterday, took grill out and slam bonnet down and like Davezj and Wodjno
clearance is very very poor so my bonnet stay went straight out :)

[swinks]

Is that really the best place to do the water meth injection, directry on to the compressor wheel, I thought it was supposed to be in front of the throttle body.
There are 2 different approaches: as you mentioned - prior to TB, or directly prior to turbo compressor intake. First option is most common, but there are also several build-ups of second option setup.

[swinks]

If u were to spray water/meth into the compressor I would like to see the results. As the wheel would quickly wear away from the abrasive properties of the water. Throttle is much better for input location. U would also get more heat transfer as the air is much hotter having a better vaporisation effect.
False statement.
Unlike you, I did use methanol injection in practical level. Been sitting in my vr4 for 3 years. And I did try several setups to get optimum results, not to mention about endless research regarding methanol injection.

[swinks]

That's exactly what I meant. There is no point playing with pre turbo pipes, post turbo pipes, upgrading throttle body to a bigger one, unless you've increased an air entrance to the air box. Without it you wont benefit from your upgrades.
I would be careful with this statement, tho :)

[swinks]

Hey swinks. I have already addressed the dumps as a restriction. Refer to pics.
http://img.tapatalk.com/d/14/01/29/9ygepehe.jpg

http://img.tapatalk.com/d/14/01/29/adeny8er.jpg
Glad you did it, but seems that this issue been ignored.
Like other major things: cam profile, size of turbo hot side wheel, etc.

And because you are dealing with FORCED INDUCTION then following items will play decisive role: turbocharger, camshaft profile, intake manifold (runners, chamber), throttle body, and exhaust manifold.
Once all above is up to optimum size/shape etc. to your desired output, you can play with remained: air delivery and exhaust.
Saying in other words, with vr4 you can throw as much you want massive air intake, massive exhausts, spend billions of wonga, but you won't gain anything significant till you not sort out such bottlenecks like tiny nuts size turbo and silly camshafts.

[fassi1]

Glad you did it, but seems that this issue been ignored.
Like other major things: cam profile, size of turbo hot side wheel, etc.

And because you are dealing with FORCED INDUCTION then following items will play decisive role: turbocharger, camshaft profile, intake manifold (runners, chamber), throttle body, and exhaust manifold.
Once all above is up to optimum size/shape etc. to your desired output, you can play with remained: air delivery and exhaust.
Saying in other words, with vr4 you can throw as much you want massive air intake, massive exhausts, spend billions of wonga, but you won't gain anything significant till you not sort out such bottlenecks like tiny nuts size turbo and silly camshafts.

How much is cam regrind or adjustable cam pulleys?
My extra ducting cost me about £30 in parts.
What's the point of going first in to the most expensive upgrades if ur turbos have to spin stupidly fast gettig glowing red hot just to produce 1.2 bar.

[Trotty]

We are in the process of having high flowd turbos produced. First set has been made waiting on fitment and tuning. These are only larger on the exhaust side. Using same shaft but stronger metal to stop the shaft shearing. This is the main reason I have done a group buy on dumps on ozvr4.

[Anderz]

Agree that the small turbos and cam profiles are the main restrictions, change those and you can get huge gains.
But removing vacuum before turbos inlet always helps. This means the turbo runs a lower pressure ratio at the same flow and boost

[fassi1]

I think that we miss understand each other. We are not talking, at least I'm not, about 400+ buildup.
We are talking about healthy strong figure on stock turbos and the thread is about improving air intake.
If the stock snorkel seats in the low pressure zone, what is the point going in to custom cams and bigger turbos which are huge costs,
may as well do evo conversion and forget about small bhp figures.
My goal is to minimise vacuum level at the entrance of the air box which is still existing even with added 60mm OD ducting.
Once I'm happy with it I may start thinking about other upgrades but at the moment they just don't make sense.

[adaxo]

False statement.
Unlike you, I did use methanol injection in practical level. Been sitting in my vr4 for 3 years. And I did try several setups to get optimum results, not to mention about endless research regarding methanol injection.

I must mist your thread about it somehow :idea2:


I think that we miss understand each other. We are not talking, at least I'm not, about 400+ buildup.
We are talking about healthy strong figure on stock turbos and the thread is about improving air intake.
If the stock snorkel sits in the low pressure zone, what is the point going in to custom cams and bigger turbos which are huge costs,
may as well do evo conversion and forget about small bhp figures.
My goal is to minimise vacuum level at the entrance of the air box which is still existing even with added 60mm OD ducting.
Once I'm happy with it I may start thinking about other upgrades but at the moment they just don't make sense.

Eventually someone put this what I was thinking about all morning in words :)

Its £ for HP what's matter, I'm not saying that big cams/tubs ect will not give you big bhp figures, but IMO we should do it when we really squeeze our tubs to the limits first, not by starting pouring money on cams/tubs/pistons and other forged things while simple/cheap hp are here just waiting to be release :)

[Davezj]

i have been doing some reading on bell mouth inlet, inlet trumpets, velocity stacks.
i have come to the conclusion tha the turbo needs to have a bell mouth inlet on it to improve flow. i know the turbo inlet is slightly beveled but this is not enough in my view now.
my thoughts are silicone hose from turbo inlet (very short) to the back of a a bell mouth inlet. but you will need 2 or 3 layers of silicone hose to bring the level of the outside of the layered silicone hose to above the outside diameter of the bell mouth inlet.
then a silicone hose goes over the bell mouth inlet and gets secureed behind the bell, so the bell is inside the large silicone hose you have just fitted.
the turbo inlet now effectively starts from the bell mouth inlet, admitedly this make the length of the turbo inlet longer, but from what i have been reading the pros should out weigh the cons. it should flow better.

But this is just a theory.
the turbo inlet is so short at present it might not make any difference, but on the other hand it couldd make things better.

[fassi1]

Front turbo pipe. Rear pipe and Y joiner hopefully comming soon.

[Davezj]

your going for aren't you chris.
this will be interesting to see at eurospec if you have it finished.

[scott.mohekey]

Front turbo pipe. Rear pipe and Y joiner hopefully comming soon.

Needs more lobster.

[Trotty]

Nice work. Should do the job nicely. Have u noticed slight improvement in throttle response?

[Badger_01]

Needs more lobster.

This

[fassi1]

I didn't have enough time to get any feedback from it but I think that Y joiner should make the biggest improvement and bring this pipe to live.

[Nick Mann]

Needs more lobster.

Scott, I have no idea what this means!!!

[Trotty]

Scott, I have no idea what this means!!!

This is a lobster back bend
http://img.tapatalk.com/d/14/02/14/u4ugany9.jpg

[scott.mohekey]

Scott, I have no idea what this means!!!

Lobster welding is a technique for making bends in pipes from straight sections. It's called lobster because it looks like a lobster's tail.

For example:

66556

[fassi1]

Correct I could make one bend a little bit smoother :)
Will get it corrected when doing back bend.

[Nick Mann]

Thanks for the replies. I even googled it but could't work it out!

[fassi1]

It's the bend just after T section is bit tight, all the others are fine to ne.
I guess this must be the detail which mskes all the OZ and NZ so much more powerful than UK VR4s :)

[fassi1]

Rear turbo pipe and partly done MAF bend which hopefully will be finished by the end of the week.

[Trotty]

Lookin good. I would say more silicone on I take is better as wont absorb the heat.

[fassi1]

Having fitted front and rear turbo pipes with stock maf bend I have to say that I can't feel significant difference.
Hopefully custom maf bend will make an improvement.
I done some loging with both turbo pipes fitted and gonna do the same with custom maf bend so will be able to compare some data especialy air flow,
which hopefully will increase especialy past 5000rpm.

[Trotty]

Without dumps I don't think u will get too much top end improvement. What u may get is cooler charge and inlet temps as the turbos arnt having to work as hard to create the same amount of boost, as they don't have to make up for the 3psi drop at inlets.

[fassi1]

Will have to get my head around makibg dumps too but defo not before 22nd of March.
The range needs to be improved is 4500-6000 cause it looks like as soon we go over pick boost and power manifold pressure starts dropping and air flow
from about 4000 up to 7200 remains constant, at least that's what I experienced doing last data logs.

[adaxo]

Looks like you're going to stick with TD03s?

[fassi1]

Who knows Adam. For now I want to finish building an intake (low pressure side) and hopefully get some good figures,
I have my little target :)
To be honest car feels really strong at the moment and it's far enough ( even bit too much ) to have good fun driving it.

[adaxo]

Who knows Adam. For now I want to finish building an intake (low pressure side) and hopefully get some good figures,
I have my little target :)
To be honest car feels really strong at the moment and it's far enough ( even bit too much ) to have good fun driving it.

Yes you right, mine is also pulling like a train, especially at WOT on 3th and 4th gear its still raise my hair a bit BUT after a long think I decide to (try) stick bigger tubs, why? I just don't want to pouring money in intake pipes, dumps, machining td03 to make them bigger and unreliable (shaft issues), and after a year or so and few £100 spend/waste? start from scratches with td04 anyway (as all of us will do at some point) as we all know this mod will bring vr4 in close to how much?? reliable 400HP? and then it must be a really nice thing to drive.

This was on plans to do since we spoke at some meet (JP2?) about fairly pointless mods which costing fair bit with very little BHP gains (bigger TB, intake piping, downpipes ect), I just didnt expect this will pop on sale so quick at so low price. Anyway /Hijack ends now.


btw

I have my little target

which is ???

[fassi1]

I still reckon, that no matter what turbos you have fitted, you have to have your low pressure intake midified as well as exhaust side. You can't keep stock snorkel running td04s cause that's making car very unreliable.
Unfortunately Adam can't tell you my target :)

[exevoowner]

Would it be worth making a new snorkel out of aluminium to fit under the slam panel with it modded to allow direct air intake i know it would take some making

[Nick Mann]

The rads are under the slam panel.

[swinks]

Relocate battery to boot and do the air vent in a bonnet. Simples! :)

[fassi1]

Finally fitted MAF bend.

[exevoowner]

That looks sweet

[Trotty]

How are the vacuum levels compared to stock? I'm keen to see what mine is in comparison

[adaxo]

Looks good, as usual, I would use hump hose on both ends to let a little movement while engine moving, this connection as solid one may damage your maf or getting lose and let undeterred air in.

[fassi1]

Black silicone piece for front turbo pipe is a hump and rear turbo has 2 silicone bends.
There is a lot of play, front pipe hase more silicone pieces untill it gets to the front turbo.

[MarkSanne]

Impressive! Hope it will prove itself worthwile!!!

[fassi1]

How are the vacuum levels compared to stock? I'm keen to see what mine is in comparison
I won't be able to test vacuum levels, don't want to make any holes in the pipes.
I can test air flow with maf bend in. I tested it without maf bend, so comparison will be possible.

[exevoowner]

Hows this looking compared to standard (bump)

[fassi1]

Didn't have time to test the airflow with new maf bend.
It definitely feels good.

[AKKO]

Looking forward to seeing the numbers when you get a chance, keep up the good work!

[Trotty]

Mine goes back this weekend to get tuned with new engine mounts. False knock stopped me at 196kwatw 389nm. On 16psi flat boost curve to 6.5k as he backs off before cut

[Davezj]

Mine goes back this weekend to get tuned with new engine mounts. False knock stopped me at 196kwatw 389nm. On 16psi flat boost curve to 6.5k as he backs off before cut

That sound like a good, keep the results coming.

[fassi1]

Looking forward to seeing the numbers when you get a chance, keep up the good work!
Should know some results in 2 weeks time.

[fassi1]

Mine goes back this weekend to get tuned with new engine mounts. False knock stopped me at 196kwatw 389nm. On 16psi flat boost curve to 6.5k as he backs off before cut
16psi at 6500rpm sounds very good. Looks like dumps doing very good job.
What's your target max boost? Are you running stock ecu or ebc?

[Trotty]

16psi at 6500rpm sounds very good. Looks like dumps doing very good job.
What's your target max boost? Are you running stock ecu or ebc?

Stock ecu. Running 3 port tune. I'm looking at pushing the turbos next tune to maybe 20psi to see if outlet temps rise to the point it's just heating the charge. And that tune was on a 42*c day

[AKKO]

Seems i may have found myself an ARC super induction box, should provide some interesting test results combined with my vented evo style bonnet to further add to these discussions. Going to relocate the battery and investigate some additional ducting routed up to it from between the intercooler and passenger side foglight.

[kiwigalant]

I've looked at the pics in the first post about the clearance underneath the bonnet and it got me wondering. Has anyone thought about creating a custom snorkel maybe a bit wider and definitely taller than stock which goes through the slam panel to the grill? As in modify that section of the slam panel to be further down to allow the snorkel to slope down it to stay within the clearance which is like a staircase. I imagine this is a lot of work and maybe not advisable due to having to modify the structure, but it seems like a reasonably direct path which will look stock in the end.

[Davezj]

you could probably do that but you still have issue with the snorkel having to go over the top of the radiator and under the bonnet. which still be very tight.

what you have to remember, there is a air con rad under the slam panel. the most direct route is something rikki has looked at, and cut a vent through the bonnet directly into the snorkel.

[kiwigalant]

Yeah and I guess you couldn't increase the height of the snorkel much because the bonnet might smash it when it gets closed and then springs up to normal height. But the air con condenser seems to only take up half the depth under the slam panel and nearer the radiator. Still not a lot of space to use, there just aren't easy paths out the front on these cars are there.

[Davezj]

this is why i think people are going down the adding an extra pipe to the snorkel of dirct to the air box (before the fillter), both will have the same effect. i think the bottom of the snorkel is equally acceptable.
th bottom of the air box would probably be my choice but that is just personal preferance, however having an auto gearbox myself it might be to tight to get the pipe to fit in that particular location for me. i have a lot of other stuff in that location as well.

[Trotty]

Yeah this is what I've done. http://img.tapatalk.com/d/14/03/27/e2e8ebyq.jpg

[kiwigalant]

I'm guessing because many people are doing it that having air come into the box or snorkel from multiple directions doesn't add turbulence to the flow as such or is it just a by-product to a greater intake?

[scott.mohekey]

The filter will sort out any turbulence.

[AKKO]

Yeah this is what I've done. http://img.tapatalk.com/d/14/03/27/e2e8ebyq.jpg

Loving the OEM paper filter!? :-/

[kiwigalant]

The filter will sort out any turbulence.

Time for me to find some piping, a funnel and things to mount them to the car with lol.

[Trotty]

Loving the OEM paper filter!? :-/

Yep and still making 210kwatw lol