Moles Dad

As title, does anyone have any data on the use of (APS?)in the wing type cold air filter kits versus an under bonnet type induction kit?

I was going to start my 'heat box' home made induction kit cover today when I thought that it was a 'full circle' issue, remove what is already a cold fed air box, fit a filter that then sucks in 'hot' air and then design and build a box around it in a bid to reduce air temperature???????

My reservation on the 'in the wing' kit is the water and grit issue, how is this overcome? other than only drive the car in fine weather?

Has anyone 'extended' a MAF connection and put a K&N or similar into the wing? and if so to what success?

john banks

The APS induction kit REQUIRES remapping, but sits on a linear rather than exponential area of the MAF sensor response. For this reason I asked Jamie for a K&N 57i.

Moles Dad

JB, to be honest I dont know what that means!

I can presume that the air flow is related to the road speed or am I talking 'lox?

Is the 57i under bonnet with the heat shield thing?

harvey

iTrader: (48)

The air flow past the MAF depends on engine speed. Road speed has little effect on the air in the inner wing other than the air forced in via the small grill, if your car has one, venting into the inner wing.
Having fitted an APS cold air kit I was surprised how clean the inner wing area is and grit and water have not been an issue but the plastic inner wing is in position in reasonable condition.
APS state that their filter kit should not be fitted without a re-map and from what I have learned I would not fit this kit if I was still relying on the MAF sensor (I have a Link and no MAF)
I think there must be gains from cold air done properly but how much of a gain I cannot quantify and clearly Subaru have put a lot of thought into the resonator and induction generally. On the move the temp differences from inner wing to under bonnet(behind drivers side headlight)) are about 10cent.
On a WRX with a GGR/K+N filter kit I used some plastic pipe about 9ins dia to box the induction to the inner wing with resonator removed. The pipe was profiled neatly to the engine bay shape, sealed with tank tape and covered with silver heat reflector.
I know it worked well presenting colder air to the engine but I think an important part was a shaped aluminium bellmouth as part of the GGR kit which ensured air went to the MAF sensor in an acceptable form.
Have some photos of it somewhere.
Gains are probably marginal but many a mickle maks a muckle.
Hope this is helpful.

Andy.F

Absolutely mate

Moles Dad

harvey, thanks for that.

I wonder why APS suggest a remap, is it quantity of air ? is it lower air flow or higher air flow ?

Is it the lenghth of the induction hose....dunno!

Pavlo

the Maf sensor is put into the APS pipe, and doesn't read quit the same as when in the factory housing. As a result, it seems more air in general flows for the same voltage output, and this effect is greater at lower airflows.

Causes lean running inother words.

You might just get away with fitting an adjustable fuel pressure regulator and upping the fuel pressure to compensate. But if you are thinking of going Ecutek, then wait till then,

Paul

Bob Rawle

Moles Dad, I think you have inadvertently opened the proverbial can of worms here ...

I have some VERY practical experience of the effect the APS cold air induction kit can have on a car running with (relying on) a maf sensor, the car in question was a P1, owner was sold and then fitted himself one of these kits, it was fitted correctly. The car was almost undriveable, the kit had caused the maf sensor to under read by approx 27%, yes thats right, 27%, if he had been less aware his engine would have blown up in a very short time, for those that appreciate numbers oxy sensor voltage never exceeded 0.42 volts ..... touch lean methinks.
I use one of these kits but have never, until recently, had a maf in the car, since the state of tune of my car is far far away from std then it never ocurred to me that there might be an issue here. Four days ago I substituted another induction kit for the APS one, this was the HKS SPF DD, it has specific features that help flow air over the maf correctly. The difference ? In boost terms ( Jecs is callibrated in CVL which can take a bit of getting the head around) up to circa one bar I had to REMOVE 9% fuel, above 1 bar I had ADD 7 % fuel, in other words the APS was screwing with the maf output big time. The relative percentages are lower due to the 740cc injectors and uprated fuel pump I have fitted. I would add that peak maf voltage is now higher as well.

If fitted with a Link/Motec/Pectel or something that does not use the maf as its reference then it works well, BUT DON'T INSTALL THIS FILTER ON A CAR THAT RELYS ON A MAF AND USES STANDARD ECU SETTINGS, it could cause engine failure. It won't work with any ecu unless specifically mapped to use it and then, if removed and some other induction installed, the ecu could end up runing the car extremely rich. (maf reliant setups)

Before anyone jumps in I have EXTENSIVE data to back this up and am continuing to pursue the issue. The last time I personally tried to advise APS that they had a problem with a product the response was, to say the least, "head in sand" related, for that reason I will not be contacting them but I am more than willing to share my experience and data with anyone who genuinly wants to get involved in this. (and that does include APS if they are so inclined). I also know that one member of this bbs fitted a kit and ended up having his engine rebuilt !! ( apologies for mentioning but this is a serious issue)

The first choice of substitute induction was K & N but I could not get it to fit in the engine bay with the APS FMIC ... So anyone wanting to buy a GGR/Mac'sPower induction kit at a discount email me off line. (and yes we do have a banner ad)

I would repeat that if you use this kit with an aftermarket ecu that does not rely on the maf then it works well.

The APS kit moved the whole of the airflow curve into the first 30% of the maf calibration which is the more linear part of the maf airflow v voltage curve, its actaually exponetial in shape and the remaining 70% of airflow is mapped in the last 1 volt of maf output the first 30% being mapped into the first 3.6 volts (in practice less than that as a car won't drive at less than 1 volt maf output).

Since I'm still working on this I wasn't going to post anythinhg but since this has been raised I feel it only right to publish my findings so far.

APS web site does not suggest a remap but does state that the if the kit is used without aftermarket engine management then "best results" may not be obtained ... not quite the same thing ... damn expensive air filter if it needs a remap methinks.

cheers (this is not a dig at anyone ... blown engines are a serious possibility though hence my post)

Pavlo, the kits in Uk do not have provision for maf fitment if MY/99/00, are you refering to MY01 on ? I am specifically talking about MY99-00 cars in this respect.

Bob

[Edited by Bob Rawle - 8/25/2002 11:28:37 PM]

ustolemyname??stevieturbo

iTrader: (1)

Maybe I missed it...Does this actually mean the the APS kit flows substantially more air than any other kit, or just that it completely messes up the way the air flow over the MAF causing innacurate airflow readings?

Bob Rawle

No it doesn't flow substantially more air, but yes it definately screws the air flow pattern thro the intake, just how much and how I am still working on. Map for map the APS makes the maf generate less output, that means lesss air flow in the centre of the pipework. The car (P1) that I mentioned only had the APS induction and a back box, even had the original downpipe.

harvey

iTrader: (48)

The APS C.A.K. uses the MAF sensor in the existig black plastic housing.
Having fitted this kit in February I picked up the piston in No.2 bore within 10mls. I had also removed the bumble bee mesh filter at the front of the MAF housing and at the time believed the air flow presented to the MAF sensor was in such a changed state that the sensor did not function correctly, weakened my mixture very substantially and hence an expensive rebuild on a 14k mls STi 6 engine. (It did set me off on the " search for power" trail.)
Even with the mesh back in and still after the rebuild the car ran very poorly until the Link was fitted and a remap took care of fueling needs.The Link was on within days of gentle driving after the rebuild.
Had I had an air/fuel ratio meter and Knock Link fitted prior to the C.A.K. I would probably have realised the nature of the problem and saved the original engine.
APS knew of my experience in great detail but as I said I put it down to a problem compounded by bumble bee mesh removal.
I now know of two subsequent owners who fitted the CAKs without remaps and were alarmed by the degredation in performance to such an extent that one told me he had the kit off his car next day.
When I reflected on all of this I did wonder if it meant that the APS C.A.K. was flowing much more air but I do not think that is altogether the case and as I said, I do think that on the GGR/Macs Power kit the alloy bell was intentionally or accidentally an important part of the set up

NINJA

bob i have this cak at moment.does this mean it wont work correctly with my remap you are doing.i dont really want to start buying another air filter.if u map with this in place will i be fine if i dont change filter and stay with aps.did u have to modify the hks to clear the aps pipework..tks paul

Bob Rawle

If a remap is done with the CAK in place then yes, for as long as the filter is not taken off it "should" be ok since the mapping will take account of it. The different airflow thro' the maf causes it to read much lower than "normal", the mapping will effectively offset the whoe fuel map (and timing map), don't forget that if the maf output is lower timing will suddenly become much more advanced for the same "load" as well as fueling leaner. Since boost is governed by throttle position (TPS) and rpm then the ecu will still be trying to make the same boost but the maf output being lower it will be leaner and more advanced.

john banks

Bob is it just the GGR version with the STi type bellmouth of the K&N that does not fit with the APS induction kit as I was planning the plain old 57i with my APS induction?

Pavlo

wow, I thought the biggest problem was caused by fitting the factory maf sensor in the APS tube. But your saying it screws it just putting it on the end of the factory MAF barrel, which is a bit extreme.

Thing to do would be to get the aps kit and MAF on a flow bench and try and calibrate it. Which is something I think APS really ought to do themselves.

Paul

EvilBevel

This might explain Wrexy's strange DeltaDash outputs ... (he had the CAK if I'm not mistaken).

Paul, calibrating it may prove to be difficult... in the original setup the air leaves the filter into the MAF housing almost at a 45° angle. I don't know how airflow works, but surely that must have an effect as to "how" the air flows past the sensor. The MAF/ECU was then probably calibrated for this setup.

I have tried the GGR/Macs Power kit for a month and although it seemed to lean out the car marginally at mid RPM or at the moment of building boost (without a remap), it looked pretty normal on my AFR (nicely rich at full boost/top end). I didn't want to risk running it on track without a remap, so put on the standard box again in the mean time, but it does seem like a very nice setup.

Bob, sorry for the slightly off topic question, but will the GGR/MP K&N fit with a Pace FMIC ? Ideally both should go on the car today, but just would like to know if I can expect a phone call from the fitter

Jamie Whitfield

HI

Just thought I'd pop into say that I always advise the customer to remap their car if they are going to use the APS HFA, as myself (and APS) are fully aware of how they effect the engine without one.

I must also say that John, Bob and Harvey have been the three best sources for information on tuning using these filters - thank you all.

Jamie

www.j-w-racing.com

WREXY

Theo,

True m8. My car is running leaner with the APS induction kit fitted. I get 0.86/0.88Volts with the standard ECU. I guess I've been lucky nothing has gone wrong yet in the 15000km I have done with it so far. I have stopped giving the car any stick untill I get a Tek 3 done and now I'm trying to decide whether to keep the APS or go for something different. I'm sure it helps heaps with induction temps and my knocklink shows no detting.



Bob, John, and techies,

I'm going to get a Tek 3 re map with a VF23 turbo, 5 Zigen exhaust, (2 3/4 inch) (mid and backbox only with stock down pipe) and my Blitz boost controller. Should I keep the APS induction kit or go for somehing else?

Cheers,

Wrexy.

harvey

iTrader: (48)

Bob is exactly correct again in that the APS web site says that for best results the cold air kit should be fitted in conjunction with with an after market engine management sysyem. It does not say a remap is required as I stated previosly. I am happy for my CAK to remain as I have no MAF sensor but APSs preferred route is a Unichip fitted by a 4WD rolling road operator. This still relies on the MAF sensor and I do not have the knowledge to know if this is adequately perfected to be an ideal solution or just a crude fix. It will be interesting to hear the views of those with a technical expertise and experience in this area.
What a can of worms!!!
Thanks for your words Jamie but I do not consider I have that much technical expertise. I am just relating my careful observations and experiences to others in the hope we can all learn and understand the implications of what we are doing. An engine rebuild is expensive so if someone can avoid that in part from my unfortunate experience then that is a good thing.
Thanks for expediting my APS silicon hose requirement so promptly.
I do hope APS are as responsive.

NINJA

bob can u send me picture of ur hks kit fitted.tks paul

Moles Dad

Bob and all, seeing that response as I surfed through the bbs knocked me sideways!!!

I have indeed, inadvertently opened a can o' worms...but if it stops someone blowing their engine then bring on those worms!!!

Do people believe the 'problem' is the velocity of the air is changed due to the length and the bend in the pipe...makes sense to me, the speed of the air will differ when trying to 'turn a corner', faster on the inside of the bend etc.

I will stay with my 'hot' filter for now

swan

Excuse the ignorance but how can you by simly using an aftermarket ECU bypass the MAF altogether? Do you then simply link rpm's to fuel mixture?

Moles Dad

I believe an ecu which does away with the MAF uses a programmed 'map' for fuelling, this is 'tuned' to the specific car either on a rolling road or out on the real road using software and lap-top.

Pavlo

Link, Motec, Pectel, Gems, Autronic, Emerald and DTA (and others I am sure) ECUs don't use MAF sensors at all. They map fuel and ignition based on RPM and either Manifold pressure or throttle position, and the data in the map tends to be injector opening durations.

You would tend to map a normally aspirated car on throttle position, and a turbo charged car by manifold pressure.

So if you fit say, a Link ecu, you can replace the MAF with a plain pipe, or fit a custom inlet arrangement.

Paul

Moles Dad

Or even an APS cold air

Fuzz

so with all this in mind is'nt it easier to run the car with a MAP sensor instead of a MAF?
what advantages has the MAF got over the MAP for it not to be used in the first place?

Andy

john banks

MAF systems seem to tolerate breathing mods and environmental variations very well since the amount of fuel is determined by airflow, rather than boost and engine speed with measurements or assumptions about temperature. Of course the MAF is a restriction to airflow and potentially brittle.

Bob Rawle

The alternative ecu's mentioned are all well able to take account of temperature, its just a different system of picking a load point, in practice the maf is similar, TPS plus maf voltage and rpm combine to generate a load point, map plus TPS plus rpm do the same thing ... compensations exist for both systems dependant on the complexity of the ecu in question. Its clear that the maf based system is far more likely to be affected by air flow patterns and other external influences than the map based one though since it (maf) must be callibrated to the "system" it sits in, map based only needs to generate a correct voltage with respect to pressure, the induction and exhaust system cannot affect that. So given there is a mechanism to generate load point all that is needed is to program in the required fuel level to suit the application ... not quite as simple as it sounds but the essence is there.

john banks

Bob, where is it best to measure the temp for a speed-density system? Should it be charge temp? I have read about the intercept Link - can you tell me more? Is it a viable solution for JECS?
Will the 57i fit the APS FMIC and what you were saying only applies to the GGR version (which is bigger?)

[Edited by john banks - 8/26/2002 4:41:47 PM]

Bob Rawle

Read it in exactly the same way as the maf based system, its no different. The maf based jecs merely looks at intake air temp, so does Link and Motec etc, in practice you and I know that the Jecs temp compensation map is flat. Link has a reducing compensation to allow for temperature change with a mappable start point for example but as a map based system is speed density it automatically compensates for pressure changes (density) in itself. (uses absolute valuse) The advantage of the other aftermarket ecu's is that you can apply compensation based on almost anything you want.