My Dyno Result - Diognosis help please?

[Si.]

OK so Sunday UJCC held a Hampshire and Dorset RR day at Triton Motorsport in Bornmouth, and i thought what the hell, first opportunity to see what shes running like.

Now i have always thought there was a really bad flat spot after 5500 RPM, ie she jut stopped pulling. I also had concerns that she just wasn't that quick. Although she felt fairly quick, there were certain moments where the renouned performance of these cars was not stacking up against cars that had been "killed" in drivers stories and such like on here.

The dyno on the day has since come to light had a slight intermitant problem where the fly whell figures were really low, but it seems WHP is pretty good. Unfortunately i think i was not one of the unlucky ones and got an accurate (as best you can) figure.

I've attached the graph, and i'm a little trouble as to how i can solve the problem. Firstly i only pulled 185BHP at the wheels, which if you drive an auto converts to around 260 HP, but mine being manual means it doesn't infact convert to around 230 with the 24% losses expected.

It looks like the car is running really rich up until 5600, then she leans off a quite dramatically. Funnily enough this is exactly where i lose all my power, as you can see from the second graph.

It also looks like the car struggles to hold a good figure of boost, dropping off at 5600 RPM again.

Fairly impressded with the torque with around 245 ftlb at 3500 RPM.

Now what i'm struggling with is how to solve my problems and get her running back at least somewhere near the power she should be. With out full ecu mapping to remap the fueling and boost and such like, what are my options? What could be the cause of such poor performance? I'm a bit baffled and stuck, so any advice would be much appreciated. :)

[wrdmotorsport]

Hi Si , Looking at the stats you may have a weak FPR or fuel pump that can not keep the pressue when entering high boost/rpm areas .

Be aware that running the AFR around the 12 area on none forged internals can cause damange

[colVR4]

If you have not made any significant mods to the car then the graph looks about spot on for a standard car, if anything slightly better than expected. The fuelling for your car looks a LOT better than you would expect from a standard car...are you sure that you haven't got a piggyback ECU thing going on there or a fuel computer?

Only way to release lots of extra power is to get a boost controller, a free flowing exhaust, better air flow and a bigger front mounted intercooler (FMIC).

[Wodjno]

For starters your Fly HP should be 244bhp using 24% losses.. (185.6 / 0.76) So not as bad as you 1st thought.. :D

The main problem i can see is when your boost is building ! The AFR should be dropping along the RED line that i have drawn on the Graph ... The box i have drawn shows that your AFR's are leanining out as the boost is building instead of getting richer..

As stated by WRD, this could be a problem with a weak fuel pump or low pressure of the FPR or even a crapped up fuel filter.. These would be the easiest to sort first /yes

[colVR4]

The whole of the AFR graph looks too lean for a standard car. Are you sure that there is no fuel computer, chip or resistor or something that is leaning it out. There is no way that the AFRs shown there are standard.

[Wodjno]

The whole of the AFR graph looks too lean for a standard car. Are you sure that there is no fuel computer, chip or resistor or something that is leaning it out. There is no way that the AFRs shown there are standard.

The bhp and torque figures would be higher if it had been mapped.. !!

[Kenneth]

Have you done the "MAF Mod" Si?

the AFR looks fine to me, it leans out at fairly high rpm, which is normal.

[zentac]

It looks like you boost is dropping off quite a bit at the end, you may have a weak/leaking actuator that cant hold the boost correctly.

[Kieran]

Be aware that running the AFR around the 12 area on none forged internals can cause damange

Err? Really?:inquisiti Thought 12 was what we were all shooting for when on boost? 12 up untill say 5500rpm and then richen it up a bit to keep the EGTs and Cylinder temps under control?

[wrdmotorsport]

Max torque is at 11.8 , Max power is at 12.5

But these figures are based around having forged internals when I map my car it will be to 11.2->11.4 max as we are not 100 % sure on the strenght of the standards .

I know of one person who is running 12's but they have a tight control over the fueling and are as insane as me ( hello Glen )

[Wodjno]

It looks like you boost is dropping off quite a bit at the end, you may have a weak/leaking actuator that cant hold the boost correctly.

Thats a good point there Richard /yes especially as he is only running standard boost levels :thinking:


EDIT: ON FURTHER INVESTIGAION I SEE THAT THE LARGE PERCENTAGE OF STANDARD CARS THAT HAVE BEEN ON THE ROLLERS, HAVE FOLLOWED THE SAME BOOST CURVE..SO I THINK IT'S HOW THE STANDARD ECU IS MAPPED.. NOT A WEAK OR LEAKING ACTUATOR AS SOME OF THE MEMBERS CARS I HAVE CHECKED OUR NOW RUNNING MUCH HIGHER BOOST WITHOUT A PROBLEM ...


oops.. Sorry about the Caps Lock :(

[Wodjno]

Have you done the "MAF Mod" Si?

the AFR looks fine to me, it leans out at fairly high rpm, which is normal.

Going lean while the boost is building is far from normal Ken ??

[Si.]

Wow thats really thrown me.

As far as i am aware the car doesn't have any kind of fuel control. Obviously only have the car in the contry since October means i know little about the history, so perhaps a little more detailed investigation would be required. there is no obvious signs of a controller in the car, but that doesn't there isn't something hidden away. Anything i should look for, in specific places??

I know it has a Greddy speed limiter cut as the box was in the car on arrival.

I would have to say I have not done the "MAF mod" as i don't know what that is, and wouldn't know what to look for really...

It's quite amazing that there are a few that think the AFR is too lean, the guys at Triton were fairly concerned about the "running rich".

The only performance mod i know of is the exhaust which is an Apexi item, with the Cat still present. There is no boost control so standard boost is being used, so loosing some is a little worrying. It was mentioned by the guy who services my car that i may have a weak actuator after i told him about the result actually.

Even if she ran 244, still quite low i would say. I know she's a 10 year old car but for a car that should be 280 .....:speechles

So things that could do with attention for trial and error purposes:

Fuel pump
Fuel pressure regulator
Actuator
I'm thinking about a electronic boost controller anyway

Thanks for you help so far guys, keep it coming, all very useful info. :)

[Wodjno]

Wow thats really thrown me.

As far as i am aware the car doesn't have any kind of fuel control. Obviously only have the car in the contry since October means i know little about the history, so perhaps a little more detailed investigation would be required. there is no obvious signs of a controller in the car, but that doesn't there isn't something hidden away. Anything i should look for, in specific places??

I know it has a Greddy speed limiter cut as the box was in the car on arrival.

I would have to say I have not done the "MAF mod" as i don't know what that is, and wouldn't know what to look for really...

It's quite amazing that there are a few that think the AFR is too lean, the guys at Triton were fairly concerned about the "running rich".

The only performance mod i know of is the exhaust which is an Apexi item, with the Cat still present. There is no boost control so standard boost is being used, so loosing some is a little worrying. It was mentioned by the guy who services my car that i may have a weak actuator after i told him about the result actually.

Even if she ran 244, still quite low i would say. I know she's a 10 year old car but for a car that should be 280 .....:speechles

So things that could do with attention for trial and error purposes:

Fuel pump
Fuel pressure regulator
Actuator
I'm thinking about a electronic boost controller anyway

Thanks for you help so far guys, keep it coming, all very useful info. :)

So has the car just come in from Japan ??

[Kenneth]

Going lean while the boost is building is far from normal Ken ??

Interestingly enough, it is.
Had a discussion with a tuner over the dyno results from my Legnum and apparently Mitsubishi tends to tune them that way.
Apparently at that RPM the engine isn't supplying enough fuel to do damage (unless you get detonation) so there is no problem with it.

Check out my AFR graph...
The boost on the red line peaks about 11.5psi... its incorrect on the graph because their connection to the boost reference leaked.

[Kenneth]

a better boost reference... 15psi at 3000RPM and still afr of about 14

attachment.php?attachmentid=11027&d=1149545204

[amsoil]

Looks to me at about 5800 revs you are loosing either spark, (unlikely) fuel or air to keep up with the rising revs, If I was to take a stab at it I would say that your inlet is unlikely to be so very crap but your fueling looks to be the culprit.
But what do I know.

[Kenneth]

Si, are you running the standard bypass valve (BOV)?

I just remembered that at our first dyno day dickytim had poor performance compared to most (baring those of us who had faults) and later found his standard bypass valve was leaking.
The result was that his boost curve was essentially the same as yours!

He changed his bypass valve and got immediate results.

attachment.php?attachmentid=9253&stc=1&thumb=1&d=1142719331

As you can see boost has same shape, max boost looks to be the same also.


Spark issues would likely show up similar to the blue line on the first of my graphs I posted up (as thats the issue I was having)

I still cant see anything wrong with the fuel...

[bradc]

Ken, while the fuel curve does lean out, which is obviously a good thing as far as performance goes, what the UK guys are saying is that it isn't normal for our cars to lean out like that, so it has to be one of two things:

1. ecu remapped at some point
2. screwed fuel supply which is causing it to lean out

I doubt it could be the first because and WODJ said, if it had been remapped it would be making more power in the first place. I would suggest there is something wrong with either the BOV, fuel pump or fuel pressure regulator and thats causing the lack of power. I would suggest it probably isn't the BOV, because if the BOV was leaking you would expect the car to be running really really rich (the maf counts the air, but the air doesn't get to the engine), and it obviously isn't running as rich as a stock car does.

[Kenneth]

Ken, while the fuel curve does lean out, which is obviously a good thing as far as performance goes, what the UK guys are saying is that it isn't normal for our cars to lean out like that, so it has to be one of two things:

1. ecu remapped at some point
2. screwed fuel supply which is causing it to lean out

I doubt it could be the first because and WODJ said, if it had been remapped it would be making more power in the first place. I would suggest there is something wrong with either the BOV, fuel pump or fuel pressure regulator and thats causing the lack of power. I would suggest it probably isn't the BOV, because if the BOV was leaking you would expect the car to be running really really rich (the maf counts the air, but the air doesn't get to the engine), and it obviously isn't running as rich as a stock car does.

I thought I posted a couple of graphs that CLEARLY show that the standard ECU DOES lean it out. All things working as they should, the ECU runs fairly well.

[Wodjno]

a better boost reference... 15psi at 3000RPM and still afr of about 14

attachment.php?attachmentid=11027&d=1149545204

Haven't you got a fuel controller Ken ??

If so thats not a Mitsi Fuel Curve, and also looks nothing like the 1 that Si has posted..

And if Mitsi have tuned there fuel curve that way, then thats at standard boost and not for 15+psi !!

Anyway... Just my thoughts on the matter is that, while the boost is building the engine needs a good mixture of fuel /yes and my eyes an AFR is to lean.. It's not just the fuel thats important while the boost is building, it's the timing to and if you are not advancing the timing while running these higher boost levels then the sooner the AFR drops the better :thinking:

[bradc]

they do yes, but your old car was pushing a lot of power for the stock fuel pump and fpr. I do agree with what you're saying, but Simon's graph doesn't go below 10.8 the whole way across the graph, and spends most of it's time and high rpm well above 11 which isn't normal, especially for such a low power result.

[Kenneth]

Haven't you got a fuel controller Ken ??

If so thats not a Mitsi Fuel Curve, and also looks nothing like the 1 that Si has posted..

And if Mitsi have tuned there fuel curve that way, then thats at standard boost and not for 15+psi !!

Anyway... Just my thoughts on the matter is that, while the boost is building the engine needs a good mixture of fuel /yes and my eyes an AFR is to lean.. It's not just the fuel thats important while the boost is building, it's the timing to and if you are not advancing the timing while running these higher boost levels then the sooner the AFR drops the better :thinking:

Nope, that was not with a fuel controller. The first graph was with 100% standard boost control, the second with a boost controller. Yet the ECU did not change the AFR with extra boost. There was no detonation either. (was being monitored on the dyno)

The fuel curve that i have posted has a different X and Y axis scales, and therefore it is never going to look the same. This is the main reason mine looks smoother. The spike at the start just may have been that the ECU hadn't yet come out of closed loop.

The AFRs are not the same, granted. Si's AFR starts richer than mine did, but then I had the MAF mod too.

I still maintain there is nothing amiss with his afr

[Kenneth]

they do yes, but your old car was pushing a lot of power for the stock fuel pump and fpr. I do agree with what you're saying, but Simon's graph doesn't go below 10.8 the whole way across the graph, and spends most of it's time and high rpm well above 11 which isn't normal, especially for such a low power result.

His boost also doesn't top 10psi. There were 2 that didn't at our dyno day, and they got 140kw and 150kw approx. not a great deal different than Si.

Yes, my car WAS pushing good power, but the ECU still didn't change the AFRs because I upped the boost. It also didn't lean out at 4300RPM when I hit 180KW, so it was obviously capable of supplying the right fuel, and was mapped correctly for that power.

[Kenneth]

Ok, lets approach the issue from another direction

The afr curve is fairly similar to mine yes? sure, it starts a bit richer and it has more accentuated blips, but nothing significant. (and as i have stated, the graph axies are different scales)

The car also produces max power at or around 5500RPM (which it should)

So, if with those sort of AFRs I was able to get 180+KW (240+HP) then surely Si should be able to get more than 185.6hp with a similar fuel curve?
If this is so, surely if there is something robbing power, it shouldn't be the AFR.

[bradc]

yeah true, but then what could be the problem? I doubt it would be the BOV because as I said above, if it is leaking air that has been counted by the maf, but isn't getting into the engine then it is going to be really rich. If it was the plugs, the curve would be a lot more erratic. It isn't a lack of boost either, and it is a manual so it has a proper 280hp ecu.

Could it be that the ecu has fallen into safe mode from some bad fuel and hasn't reset, or could it be something like a catalytic converter that has become clogged up in the last 11 years?

[Si.]

This is where is could get interesting, I'm not running the standard BOV, i have replaced it with a shiney new HKS VTA jobby. Which yes i know can lead to over fueling issues, but there are plenty of people on here running these items and not having the same kind of power issues.


Once it was fitted, it didn't seem to make any noticable difference to either my performance or fuel consumption either, so that should be noted. I have also not experienced any of the usual, lumpy idling or cutting out that is sometimes experienced with these types of applications on this board. Infact it seems to have cured my lump idle and cutting out issues.

I seem to be getting a little confused, what kind of figures DOES make a good AFR, just so i know. I'm a little uneducated in this area, so explaining it like you would to a small child would probably get the OLD grey matter working.

OH! and yes, she came straight from Japan by the way!

[bradc]

When you're on the power, there won't be any difference with a VTA BOV, unless your original one was leaking, and in which case your power would go up, not down.

[Kenneth]

safe mode? not with a AFR curve like that. It may have retarded the timing a degree or 2.

Could always put in some high octane fuel and re-set the ECU, it cant do any harm.

Changing the plugs can be a good idea if you havent already too.

You are about 15hp off what the standard NZ VR-4s were getting at the same boost level. That could be down to differences in environment or you could have something minor that is dropping your figures some.

If you want a bit more power, you can always up the boost some and see how it goes.

[Kenneth]

in essence, the hotter you can get the exhaust gas, the more power you will make. Problem is that if it gets too hot, you also melt your pistons and possibly valves. You can also get pre-ignition/detonation, which destroys your engine even faster.

Detonation is when the air/fuel mix burns too fast and the piston cant move fast enough to prevent the pressure in the cylinders spiking. The stronger your internals (forged pistons/rods/crank etc) the higher the pressure they can withstand. The higher the pressure that can be placed on the piston, the greater the torque of the engine.
Pre-ignition is when the air fuel mix ignites before the spark ignites it and as a result the cylinder pressure peaks well before it should, placing a huge strain on the engine parts.
Pre-ignition and Detonation are different, yet they both causes large pressures in the combustion chamber and as such both will destroy your engine. Both can also occur at the same time, in which case you are screwed.

The ideal AFR therfore is determined by how much temperature your engine (determined by the material the engine is made from and the cooling capacity) can take safely before it starts to melt. It is generally accepted that if you can get around 11.5-12 (for turbo.) you are around where you want to be for power and for safety. There are other factors involved of course (there always is...) but as a general rule and everything else working as it should, 11.5-12 is where you want to be. The cylinder pressure is then affected by how much of this air and fuel you can jam into the cylinder. (assuming that the burn speed and temps are the same)

Due to manufacturing tolerances, cost, variance in operating conditions and the requirement for reliability, turbo vehicles are generally tuned to run richer than this as the extra fuel is able to cool the cylinders and also cause the air/fuel mixture to burn slower.

At lower RPM / Power levels there isn't enough fuel being burnt to melt the engine, so the ecu leaves it leaner to get higher temperatures.
Also, at high RPM the cylinder pressure drops much faster as the piston is moving quicker. This gives some added resistance to detonation

A good AFR curve will take all of this into account and generally speaking look somewhat like yours, but a bit smoother and sticking to 11.8 rather than going lower :)
It would take tuning (dyno) and monitoring of EGT to get an optimal AFR curve... however you can smooth it out and get close to your targeted AFR at certian points using wideband and some sort of fuel controller.

[Kenneth]

As I said, I dont think you are too far off the pace with your power figures so I don't think it is anything major.
Perhaps as Zentac suggested you have a lazy wastegate actuator or something.

In your situation I would service the car (plugs, oil etc unless done in the recent past) and check all your pipework and hoses, replacing anything that looks damaged and making sure everything is re-attached securely.

After that, if you wish you can up the boost a little, perhaps upgrade the intercooler and other little mods that improve performance :)

[Si.]

Hmmmmm well she only just had an intermittent service - oil, oil filter and AYC fluid changes, and only done 4k since a full service including plugs and fuel filter and pretty much everything.

She also always runs on Shell V-Power 99 RON stuff.

I could kinda understand if mine was an auto, a 20BHP lose over almost 1 years is acceptable as there isn't many modifications on the car that i know of. But i dunno, i just can't help but feel a little robbed.

I really must research this MAF mod you keep mentioning too...

Going back to previous comments where it was possibly considered that the fueling had been altered, what should i look for and where, if there is anything that is likely to be used to change this?

[Wodjno]

Hmmmmm well she only just had an intermittent service - oil, oil filter and AYC fluid changes, and only done 4k since a full service including plugs and fuel filter and pretty much everything.

She also always runs on Shell V-Power 99 RON stuff.

I could kinda understand if mine was an auto, a 20BHP lose over almost 1 years is acceptable as there isn't many modifications on the car that i know of. But i dunno, i just can't help but feel a little robbed.

I really must research this MAF mod you keep mentioning too...

Going back to previous comments where it was possibly considered that the fueling had been altered, what should i look for and where, if there is anything that is likely to be used to change this?

I don't see what difference it would make being an auto ??

You are only 12bhp down !! Not 20bhp.. Standard Pre facelift VR4 is 260ps ... Which equals 256bhp.. Your RR run equates to 244bhp..

When i first got my car, it was really down on power.. It used to struggle at 120mph.. All i did was drive it like it was supposed to driven.. Round to the redline in every gear /yes After a coupla weeks it started to open up, and eventually i hit the 150mph mark..

Have you used a 1 shot fuel system cleaner and a dekoke spray in your throttle body ??

Maybe worth a shot before you go down any other avenue... Oh yes.. And don't forget a Damn good thrashing :D

I still drive mine the same now(3+years on)

[Si.]

The autos are 260 and manuals 280 are they not? :inquisiti

[Kenneth]

The autos are 260 and manuals 280 are they not? :inquisiti

Correct (for pre-facelift auto anyway, facelift autos are 280)

[bernmc]

You are a bit down on power, but not much - have a look here (http://www.clubvr4.com/forum/showpost.php?p=153061&postcount=46)for twpsin's manual result at the WRC dyno day. AFIK his car was standard. 197.8 at the wheels, so a smidge more than yours.

Could be explained by age/oil/maintenance...?

[Si.]

Well similarities are definite in the boost graph, infact they look almost identical.

Obvious differences are mine seem to lean off a fair bit more, By 7000 rpm mine is almost at 12, where as twpsin's is nearer 10.8.

I would also say my power drops off more dramatically in comparison.

From that though it seems a little more clear that in fact she's not over fueling like triton said, but actually struggling to fuel the car more thana standard car after 5600 RPM. Unless I'm compleatly wrong and interpreting the graphs and figures in a very Noob fashion... :embarasse

[Kenneth]

Well similarities are definite in the boost graph, infact they look almost identical.

Obvious differences are mine seem to lean off a fair bit more, By 7000 rpm mine is almost at 12, where as twpsin's is nearer 10.8.

I would also say my power drops off more dramatically in comparison.

From that though it seems a little more clear that in fact she's not over fueling like triton said, but actually struggling to fuel the car more thana standard car after 5600 RPM. Unless I'm compleatly wrong and interpreting the graphs and figures in a very Noob fashion... :embarasse

Again, the graphs use a different X and Y scale, which changes how it looks.

Other than that, again there isn't a huge amount of difference, except that Twpsin has over fueling issues. Actually, I think the shape of your dyno graph is better than his.

[ako]

Most dynos read slightly different to each other, just the nature of things

Hell, even at my work we have dynapak hub dynos - i.e fcking accurate - and the 2000nm rated ones read slightly higher than the 3000nm ones. Not much, maybe 10-15hp on a 400hp car, but enough to make people cry about it.

Then you have differences on a rolling road... Different WHEEL sizes can effect your power output to a degree.

Don't worry about the power figure itself on its own, just keep using the same dyno to map what you do so you can see what various things actually gain you.

AFR's only tell part of the story. By and large mitsi's run quite rich, however a large part of that is due to most of them having dead oxy sensors (or almost dead ones) which effects your fuel trims - makes it run on the rich side of things in general. For all you know its been replaced recently and its running as it should do :)

Compared to most other mitsis... or most turbo cars for that matter, that looks about right. They run slightly lean at first to bring boost on a bit quicker, rich in the midrange for people going up hills at full noise with 5 on board, then a lot start leaning off gradually up top. Some just go pig rich up top and gain heaps from tuning (GTR's are a perfect example).

AFR going into 12's is nothing to worry about - so long as detonation is being monitored you're in the clear. There is more to a safe tune than just an air:fuel count. It IS getting on the lean side of things, chances are it may well be down to a fuel pump which is 10 years old. If your looking to be modifying the car its something you were going to be upgrading regardless :)

As for the boost side of things - its a known fact the VR4 TT turbos are way undersized for anything past factory boost. Every single one of them I've seen without fail has run a bell-shaped boost curve - comes on, holds steady for a while, then falls over up top. Good quality electronic boost control remedies it, but its a band aid fix ignoring the actual problem in my opinion.