JAMSCOOB

got one of these today that fits in the inner wing i have read a few posts seems like you need to take out the inner wheel arch linning does this go back on after or can it not be fitted, also it seems to be quite tight fitting it to the maf it seems to bend the standard intake pipe quite alot is this right cheers jamie

MrRA

Of course the lining has to be fitted again, otherwise the filter woud end up sucking in water when raining, which wouldn't have a nice effect on your engine.

I run a 65mm APS intake on my RA-R. It's worked fine ever since being fitted although I recommend it a remap afterwards as the MAF will probably need re-scaling. A quality of bit of kit though and I've had no issues when driving in heavy rain, even though I'm using a fog lamp surround as a direct cold air feed.

JAMSCOOB

lol me being silly lol

Ian

iTrader: (10)

a remap is a must with these, like above the maf will need re scaling

JAMSCOOB

so cant really go on boost to much then till get remap. are they quite noisey aswell

cheers jamie

Rob-S

iTrader: (5)

Only if you wind your window down, you don't really hear it in the cabin due to the filter being in the inner wing, adding the APS turbo inlet pipe certainly gets you more induction noise though.

harvey

iTrader: (48)

Rescale the MAF Sensor as Ian says or you run the risk of picking up a piston in the bore.

JAMSCOOB

im not to fussed about the noise. i finally fitted it and i will be remapping soon as poss. all i can say is what a fabulous piece of kit . the car picks up so much better it just feels as though it wants to go now even before boost as normally it was a bit sluggish. its made a big difference ill have alook at he turbo inlet pipe can anyone give me a link to it or one similar i have 1999 uk turbo

cheers jamie

mikey30

where did you pick the kit up from mate????
cant find anyone that sells them1!!!

joz8968

iTrader: (13)

harvey speaks from his bitter, early-days experience.

mikey30

Martin 2010

iTrader: (9)

+1

jura11

iTrader: (7)

APS induction kit selling DSAutomotives 01296 420000 http://www.dsautomotives.co.uk/
http://www.airpowersystems.com/wrx/a...stributors.htm
And as above you need remap/re scaling MAF for this or any induction kit

ginger321

Ive a version 5 sti an fancy one of those

how much do they sell for

jura11

iTrader: (7)

I think around 160-190£,but i'm not sure in US this sell for around 279$(Vivid Racing)

Splitpin

Hmmm, doesn't look as though the penny has fully dropped. The fact that you've (belatedly) told us that you have a '99 car makes this even more significant.

Just to reiterate the earlier points, if you are driving your car in a manner where you can appreciate that it "picks up so much better, it feels as though it'll go now", it's highly likely that fitting the induction kit has skewed the MAF scaling to an extent that the engine is now in an unsafe and damaging performance envelope. The mere fact that you can feel the difference in response tells us that the mass airflow scaling has been significantly altered.

If I were in your shoes, if you don't have the ability to monitor your engine's health directly (i.e. wideband airflow meter/comprehensive third party knock detection), I would not drive the car on boost at all until getting it mapped.

Also, as a more general point, is there a reason why you've fitted this part? The 99-00 airflow meter requires unusually careful thought when modifications are attempted, and over and above any issues with scaling, the sensors can be easily damaged by inadequately designed induction kits. As such, the best practice is usually to stick with the standard induction tract unless you are modifying beyond its capability.

Is your "99 UK Turbo" already significantly modified - to the point where it is running a non-standard turbo, for example? If it is still running the standard TD04, on balance the car may well be better off without this induction kit.

harvey

iTrader: (48)

Not long after I first joined the Subaru community I fitted an APS CAK to my STi 6 Wagon. I remember it was a coldish Sunday morning in February. 11 miles later I had picked up no. 2 cylinder in the bore. The car had been driven vigerously but not hard. In those days the APS CAK was the must have piece of kit. Assisted by Bob Rawle we were able to eventually satisfy ourselves as to why this had occurred. In those days the problem was not understood.
At this time I was involved in discussions with APS on unrelated matters and their engineering director actually spent two days with me in Darlington. He would not accept the root cause and was hostile to my suggestion that their kits should bear a warning that as a minimum a MAF rescale was required. I was not looking to APS for any contribution to my mishap but I wanted other fellow owners to avoid what I had just experienced.
APS attitude was such that I decided these were not people I wanted to be associated with.
BTW as space in the inner wing is restricted there is a limit to the size of filter you can get in there. I was advised by K+N that the filter in use on the APS CAK was designed for 309 bhp application.

Now had it not been for my mishap I would never have had to rebuild the engine or take an intense interest in the Subaru engine and engineering in general, I went on to do a lot of Subaru development work, won Scoobyshootout and hopefully made a worthwhile contribution to the Subaru community in general so I guess APS actually did me a favour.

Turbovin

iTrader: (2)

I have fitted an AEM Dryflow filter in the inner wing that supports at least 800 hp, but I had to make a new lower part of the splash guard in thick rubber to make it fit Not using the APS hardware but my own though, and also on Simtek.

Splitpin

A sobering example to some here, hopefully.

I would suspect that the main reason for its "must have" status was that people were getting so carried away with the instant bolt-on power boost that they spent far too little time working out the difference between APS' sales bull and how the increases were really being achieved.

While the community is generally more knowledgeable now, there are always a few who claim that modifications like this can be bolted on without any potential downside (or need to rescale/remap/accommodate/etc).

As Harvey has already said, the space within the wing cavity greatly constrains the size of filter you can fit there. I would thus be rather surprised to find that this filter will support a figure anywhere near 800bhp without becoming a bottleneck, no matter what the manufacturer's figures may claim.

Turbovin

iTrader: (2)

No it's big enough, it's 8" tall. The smaller 5" filter has been used on 600-700 hp applications. But as you can see, I cut of the lower part of the stock splash guard and made an own in rubber which gave me some more space.

Martin 2010

iTrader: (9)

ohh tempted lol

harvey

iTrader: (48)

What is the construction material of your filter out of interest.
You certainly have a bigger filter in place but it is not an 800 bhp filter.

I am sure it has but the question is : What was the pressure drop?
You may well make do with a particular filter but if you have not measured the depression in the inlet tract and found it close to zero then making do is exactly what you are doing. I use Magnahelix guages for this purpose so it is not a guessing game.

Turbovin

iTrader: (2)

http://www.aemintakes.com/dryflow_air_filters.htm

Do you have a flow rating for the K&N filter included in the APS kit? The 5" AEM filter with a 4" inlet has a flow rating of 1170 CFM. The 9" filter is a popular choice on the single turbo Supras.

Turbovin

iTrader: (2)

Seems you were right, AEM got back to me and my filter is only rated to 847 CFM, I guess the 3" inlet limits flow quite a lot compared to a 4". But the 9" filters with 4" inlet can be taken real high. Unfortunately theres no room for 4" piping without cutting the inside of the wing.

However it's enough for my car at 370 hp and should be ok for a bit more.

Sorry for the misinformation but I was convinced that it did flow more than that

harvey

iTrader: (48)

I am glad the new information will be of assistance to you.
There are dozens of guys out there with air filters that are nearly big enough to run my tuned lawnmower engine (ported induction, ported exhaust, increased compression ratio) naturally aspirated
I had not been involved in Subarus for long when I realised how misguided a lot of the thinking was on air filters. The car in question produced 417 bhp at a Southern rolling road day at G-Force. This was in the days when the experts knew that 2 litre Subarus could not produce 400 bhp. Following a comment from Chris Davies the Australian rolling road operator, I came home, removed the APS CAK, fitted a shorter inlet tract and the biggest air filter I could get in the space. This was about a foot long and 4" cylindrical. The following Friday I returned to G-Force and 434 bhp straight off. I then drove on to Bob Rawle's and we mapped the car the next day. I then returned to G-Force during the following week 452 bhp.
So 35 bhp for a filter change and map.

Now I have lots of other examples since and one of the most startling recently was Iddy/Paul Armin who gained over 50 bhp from junking his inner wing filter on his 500 odd bhp 2.5 litre. He was most sceptical and argued it was unnecessary but he is now a convert and over the moon.

Splitpin

These flow numbers you're quoting are largely meaningless without knowing what pressure drop is involved at any given rate. There's also a knock-on question about filtration efficiency too.

The bottom line is that a standard panel filter and airbox is capable of having 847 cfm sucked through it. However, there will be a humungous pressure differential caused - and thus, as Harvey says, trying to run an engine in this condition would lead to a significant bottleneck and power limitation.

In addition, designing a filtration system is a pretty simple process and there are no magic bullets. If manufacturer X claims that his filter will flow significantly more air at a lower pressure drop than others of identical size, pretty much the only way this can be achieved is by using a less efficient filter (i.e. one that allows more foreign particles to pass though).

MurrayZA

Digging up a an old thread, but who can recommend some options on CAI? Say for 300-400bhp and 400-500bhp, 500bhp-600bhp?

B0DSKI

iTrader: (17)

I'll have a APS CAI which will be for sale hopefully next week.It's already off of the car but @ Mocom Racing till I pick my car up.
It comes complete with a larger AEM dry flow filter and extended triple ply hose so the larger filter sits right behind the offside foglight cover (See Frayz project build for pics)
Open to offers

harvey

iTrader: (48)

As you will see from the above the APS CAK is probably restrictive by 380 bhp and I am not aware of any manufactured CAK that I would recommend much beyond 400 bhp. The problem is the lack of space in the inner wing for a big enough filter and I guess long pipe run does not help. You would have to do a fair bit of work yourself to adapt a system to get a big enough filter in there for high power.
Subject to model year I have Hybrid cold air kits without the filter for £110 each.

Wmscooby

iTrader: (24)

Bit of a thread revival Harvey but what would you say is the highest power you could push one of these APS CAI kits too? Only asking as i have one with a conical K+N that i'm trying to make fit