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View Full Version : The most effective way to improve air intake?



miikka
11-05-2008, 10:23 PM
Okay. Here's the alternatives I've been thinking about. And of course, if you know some even more better way to improve intake, please tell.

- Stock intake box with better flowing replacement filter, like Ralliart
- Power intake kit, like A´pexi's cone filter
- Power intake kit, like HKS super power flow

I've been thinking to install the A´pexi cone filter, but with little mods; making plates under the filter and between the filter and engine and attach heat isolating material to it. It should keep the heat away from the filter. And with the stock intake pipe (which is attached to intake box) I'd bring some cool air to the cone filter.

djb160
11-05-2008, 10:39 PM
It depends on your budget to a large extent I guess, I like BMC stuff, but that's just me. Have a look at their heavy duty air box thing.

http://www.bmcairfilters.com/infoCDA.asp

Kenneth
12-05-2008, 01:46 AM
if you want to be effective, then panel filter into standard air box and then get a cold feed that is ducted into a hole (about 3" or so) cut into the bottom of the standard snorkel.

The reason for not going with a pod filter or the like is that it can cause disturbance in the air which makes the air flow sensor misread.

The air flow meter essentially works by measuring the pressure fluctuations in the air pressure, so if you disturb the air it usually reads much more than it should.

Turbo_Steve
12-05-2008, 02:39 PM
If you're not going beyond simple mods (i.e. keeping the factory turbos) then I'd 100% agree with Kenneth.

If you're planning to go mad, then I'd spend more money and fabricate something more suitable.

Paul C
14-05-2008, 05:51 PM
It depends on your budget to a large extent I guess, I like BMC stuff, but that's just me. Have a look at their heavy duty air box thing.

http://www.bmcairfilters.com/infoCDA.asp

I dont think these filters flow enough to support 2 turbo's.I had a boost issue where the boost would oscillate on fast spool. I have removed the bmc and the crappy mitsubishi front turbo feed. The 2 turbo's are fed seperately and seem a lot happier at spooling up. All i need is decent pipework and delivery system as its a bit temperamental at the moment.

miikka
14-05-2008, 10:10 PM
Well maybe I'll buy a ralliart filter then and modify the intake pipe :) Or would the stock filter be enough?

CANDEE
15-05-2008, 02:07 AM
I would go with an aftermarket filter of some kind. We arent exactly sure of the gains of the Ralliart filter - though will know more after the 12th of next month.. /rally

CANDEE
15-05-2008, 02:12 AM
if you want to be effective, then panel filter into standard air box and then get a cold feed that is ducted into a hole (about 3" or so) cut into the bottom of the standard snorkel.

The reason for not going with a pod filter or the like is that it can cause disturbance in the air which makes the air flow sensor misread.

The air flow meter essentially works by measuring the pressure fluctuations in the air pressure, so if you disturb the air it usually reads much more than it should.

Thanks for reminding me about the xtra cold air feed into the airbox, will have to investigate that in the very near future.. :scholar:

Has anyone tried an EVO AFM in our cars to sort this issue out? I know that Mark(ak0) used to run EVO AFM's on his 7G to stop getting fuel cut when running a pod..

We were out one night in his old car, and he was getting fuel cut like mad, and when he took the POD off it worked fine. :) He then put the EVO AFM in afterwards and with the POD on i never saw fuel cut in the car...

scientist
15-05-2008, 05:12 PM
Anything you do stay away from the HKS mushroom and the foam filters

valmes
15-05-2008, 06:34 PM
RalliArt filter or Bozzspeed into stock box.

Paul C
15-05-2008, 08:32 PM
I dont think these filters flow enough to support 2 turbo's.I had a boost issue where the boost would oscillate on fast spool. I have removed the bmc and the crappy mitsubishi front turbo feed. The 2 turbo's are fed seperately and seem a lot happier at spooling up. All i need is decent pipework and delivery system as its a bit temperamental at the moment.

I'm retracting part of the above regarding the BMC-CDA. Since yesterday i have plumbed the front turbo to the original air intake T-piece. Instead of using the mitsubishi plastic feed pipe I used 2" stainless steel pipe.
This allowed me to reinstall the Bmc Cda and so far i have had no problems. every time i try to use a different form of intake i still go back to the bmc-cda.

gee118
15-05-2008, 10:31 PM
Anything you do stay away from the HKS mushroom and the foam filters

I've the HKS foam filter mushroom with NO heat isolation from the engine.
I've read loads of palces that it is not recommended but I haven't experienced any problem personally. Am i in for an expensive shock??

Would it be easy to source some way of isolating the heat from the engine away from the filter?
Also, it's a dry mesh foam. What harm exactly am I doing to the engine?
for info. purposes - the car drives every day relatively hard ALL the time.

thanks in advance

miikka
16-05-2008, 06:07 PM
I've the HKS foam filter mushroom with NO heat isolation from the engine.
I've read loads of palces that it is not recommended but I haven't experienced any problem personally. Am i in for an expensive shock??

Would it be easy to source some way of isolating the heat from the engine away from the filter?
Also, it's a dry mesh foam. What harm exactly am I doing to the engine?
for info. purposes - the car drives every day relatively hard ALL the time.

thanks in advance

http://www.mkiv.com/techarticles/filters_test/2/index.html

Subaru ETA
17-05-2008, 12:02 AM
the pod wilkl cause power decrease due to heat from engine bay...there is dyno proof to prove this.

aslso the pod diturbs thhe airflow and cause the maf to get stupid readings

miikka
19-05-2008, 04:29 PM
And what do you think of this kind of solution?
http://img102.imageshack.us/img102/4177/dsc014535ib.jpg

Moving the battery to the boot would be very useful decision anyway, so there would be more space and that means there's more space for building intake.

bradc
19-05-2008, 08:20 PM
That isn't a bad setup, but you have to be careful about the shape of the air flow going into the MAF

miikka
19-05-2008, 08:40 PM
That isn't a bad setup, but you have to be careful about the shape of the air flow going into the MAF

And what are the ways to control the air flowing?

The filter I've been thinking about is from RHDjapan.com, Blitz SUS power filter. They're saying that it doesn't create disturbing turbulence (well, of course they're saying that....:P )

What's the optimum shape for the pipe from filter to MAF, as straight as possible? And does the material affect?

Many questions, I know, but I want to make good intake with one try :P

bradc
19-05-2008, 08:45 PM
using a panel filter or have a straight and long enough pipe is all we've managed to get working well so far.

gareth001
02-09-2009, 02:22 PM
http://www.mkiv.com/techarticles/filters_test/2/index.html

Has anyone used the Apexi filter from this review on a VR-4? If so any thoughts as Apexi claim you get a smooth airflow across the whole area of the MAF?

Dom B
02-09-2009, 02:39 PM
I am working on a system with a proper airbox but a much bigger filter and feed in. I will post some pics when it is ready. I decided to go for a smaller battery rather than in the boot. There is a lot of voltage drop on 12v wires that long, so much so that the lights can be a bit dimmer for example. You really need to run 3 wires for a boot battery install (pos, neg as chassis ground is too high resistance for the high current circuits, and alternator terminal to balance the resistance) as the alternator doesn't like being so far from the battery being fed through a resistor. You start to get a filter with resistance capacitance and inductance and strange things happen with noise sometimes causing flickering and spikes being sent to the ecu a bit like when you run a car without a battery on it which is a big no no.

nuster100
03-09-2009, 11:56 AM
If you went to a MAP2 ecu, then could you just run hardpipes stright from a filter to the turbos??

Jay

Turbo_Steve
03-09-2009, 01:04 PM
Pretty much yes, although map sensor based load calculation isn't the most optimal way of setting up your car. The ultimate solution would be a pair of hot-wire MAFs: one for each turbo, though a really good aftermarket ECU would be needed to run this setup: I know I could do it with a Motec, but I'm not sure if stuff like the Vipec or Autronic would do it.

pitslayer
03-09-2009, 02:47 PM
Has anyone used the Apexi filter from this review on a VR-4? If so any thoughts as Apexi claim you get a smooth airflow across the whole area of the MAF?
Mate bought one for his FTO, all it did was make more noise and less power, so much so on the way back from London he pulled into the service station and switched back to the old panel filter and put the front of the standard airbox back on

gareth001
03-09-2009, 03:01 PM
Mate bought one for his FTO, all it did was make more noise and less power, so much so on the way back from London he pulled into the service station and switched back to the old panel filter and put the front of the standard airbox back on

I know the FTO can be very picky on the induction kits they use (seems to be a trend for Mitsi!) - personally I have used the ITG foam filter, was excellant on the MIVEC. Did not increase noise at all until the MIVEC kicked in. performed well too.

Turbo_Steve
03-09-2009, 03:53 PM
I had a copy of the Apexi cone on mine. It worked brilliantly until it got rather dirty and started to starve the car at the top of the rev range.

pitslayer
03-09-2009, 04:10 PM
I know the FTO can be very picky on the induction kits they use (seems to be a trend for Mitsi!) - personally I have used the ITG foam filter, was excellant on the MIVEC. Did not increase noise at all until the MIVEC kicked in. performed well too.
Same as the VR4 as the maf also gets funny with air flow, your