Aztec Performance Ltd

iTrader: (234)

I always assumed that my OE airbox sucked air from the wing which is fed by a hole under the front indicators. After speaking to someone how does rallying he told me its best to remove the box from the wing and make the airbox breath better....

So today I had a poke around and turns out that an OE box pulls in air from the engine bay...there is a pipe behind nearside headlamp that goes into the wing and then into the airbox...and hence is pulling in a limted amount of air...and all from the engine bay

So I proceeded with some logic (and guidance) and removed this box and piping. Now the car is able to draw in air from the wing as opposed to the engine bay and its gets a lot more of it. Also to improve the amount of air I made about 40x5p sized holes in the airbox (below the airfilter) so that it can draw in more air than just from the OE opening. At the same time it I also removed a section of bonnet rubber from the nearside again to assist in cold air.

The result is an increase in induction noise and a noticeable amount more power. Unfortunately I dont have a RR in my back garden but I'm positive it would have gained some horses.

More air = more power

A mod that costs nothing and works a treat.

Not sure if this has been covered on here before but I would thoroughly recommend.

Bob

(Pics available)

fergie_uk

Show us the pics then Bob

kevin stanton

what about the crap thats gonna be sucked in from the wheel arch onto the maf.

the wheel arch box must be there for a reason? otherwise it wouldn't be there.



sorry... a tad pissed, hope this makes sense.

Floyd

iTrader: (9)

SIAL! Your about 4 years late mate.

But, the gain from cold air in the wing has just been negated by sucking more warm air from engine bay.

Oh, and you're actually saying that you can feel the extra performance - you must have ESP lol. Take another placebo and lie down.

F

ALi-B

iTrader: (1)

You have an air filter right? That's what stops the MAF getting dirty

The box in the wing is a resonator box, it's there to reduce induction noise.

beario

i have just made a cold air kit for my r.a....i removed all the airbox,and pipes,refitted the air flow meter where the resonator box was,used the 90 degree bend that came of the original box,slotted a 3 inch piece of round tubing with a 75 degree bend in it so it angles down towards the chassis /inner wing..(about 40cm long).then drilled a number of holes just over 3 inches wide in between the chassis leg and the inner wing(the flat panel at the bottom where the intercooler water spray sits...when the hole was drilled pulled the surplus metal out the way,got a 15 cm piece of silicon cut it down the middle and put it round the hole that was cut,just to tidy it up...pushed the metal tube through the inner wing,so about 2 inches were sitting in the inner wheel arch..then took the drivers side wheel/arch of and fitted a length of 3 inch silicone on to the pipe under the wheel arch and then connected the cone filter,once it was all secured refitted the inner wheel arch sheild,so the filter is protected by rubbish from the road and then reffited wheel....after testing with this mod,it seems to work very well and the air filter noise is 3-4 times louder than when the cone was fitted in the engine bay...dont no why,the other thing is i have a forge d/valve and that has become crazy noise,sounds like the forge is in the air filter...lol:))i think it needs setting up as when you are on hard boost it coughs a bit,i was thinking it is because there is a greater volume of cold dense air going through the intake>>i am running 1 bar with full decat..255 walboro and fse regulator????????any advise welcome..thanks nigel

Aztec Performance Ltd

iTrader: (234)

Fergie: Dont know how to host but can email to anyone who can host

Kevin: Well bevied up mate

Floyd: There is plenty of cold air in that area due to removal of the box in the wing, removal of bonnet rubber and the plastic sump guard thing. Also by removing the box it allows another big entry for cold air from wing. Guess this mod cant work as its free well it was recommend by somebody who does rallying...in theory it works and in practice it deffo works, as confirmed by my g-tech last night. You telling me you cant feel extra power when your driving

Try the mod...it costs nothing and works. If you dont feel it helps (which you wont) buy another half airbox from breakers for a few quid.

There are those who try things for themselves and others who will say to anything which hasnt been done much and doesnt cost the earth.

It works. Simple! Try it...if it doesnt work I'll eat my old manky air filter


Bob

Aztec Performance Ltd

iTrader: (234)

Also the holes arent all round...just facing the direction of the airflow.

Bob

Aztec Performance Ltd

iTrader: (234)

Nigel: I take it that the cone is low down in the wing like here http://www.steve.ukmail.org/car/ (click cool air intake)

The ecu can only compensate airflow differences to an extent....not sure what this extent is but you may need a tweak in you mapping to make the most of it as you pulling in much more colder air. Steven Done (as in the link above) experienced overboost in 4th and 5th at around 4000rpm as a result of the mod...he mapped it afterwards for the extra positive airflow with good results.

But I'm a novice on these matters. If I get a remap then I will do much the same as what you have or maybe make a bigger airbox and improve ducting into engine bay.

Bob

Floyd

iTrader: (9)

Yeah, whatever!

Your 'mate' in 'rallying' has only told you half the story. I'm the king of freebies when it come to cheap mods but you'll need to do a few more things to maximise the mod. Ask your 'mate' what to do next.

F

Aztec Performance Ltd

iTrader: (234)

Whatever what?

I'm not talking about the theory of doing this mod...I have done it. When you have tried it get back to me then.

You dont need to be a genius to work out that this mod helps taking in more positive air....or maybe the OE system sucking in engine bay air thorugh a small opening is better

Your sarcasim is most unwelcome and uncalled for 'Floyd'

Bob

Aztec Performance Ltd

iTrader: (234)

How about this then 'Floyd'. Put ya money where your mouth is...can have it RR'd in your presence with OE system and the modded one. It WILL make more bhp with the modded one.

Bob

D4V3

I was told about this last week by someone how has done this to his scoob. I took the box out yesterday and added a pipe to direct the air from in front of the car straight into the airbox.

I have definitely noticed the difference. More of a grumble and there is more power.

Dave

Floyd

iTrader: (9)

At what point did I say that I wouldn't or hadn't already done this mod? You see, I have ACTUALLY measured this mod - not 'felt it'. You did well by removing the resonator (yes, that's what it's actually called) but then you tried to improve the cold air bit further by drilling holes in the airbox. This doesn't really help because it'll suck in warm air at anything under 10mph. The difference between ambient and temp at the airbox above 10mph is about 1C or 2C. But at idle the airbox temp car hit 50-60C in summer - not good. The only way to stop this is to build another box around the airbox and duct air in from the front of the car away from the engine, which is what you did to start with in just removing the resonator.

What I disliked about your post is the fact that you could send people information that is untested (measured) and possibly dangerous to their engines and is full of 'my mate said' or 'it made the car go really fast'.

IMHO
F

D4V3

Is there anything i should be worryed about by doing this,

StickyMicky

you can get a perrin kit which removes the silencer thing but still makes it look stock, simmiler to this

Floyd

iTrader: (9)

D4V3, you'll 'probably' be OK by removing the resonator but you are likely to get more crap in the air box/filter. Be prepared to change the filter/clean more often. Some cold air kits upset the MAF and require a remap to sort correct metering IIRC. This mod is a small improvement and IMO should be done along with other mods to make it work really well.

It has been documented a few times on here and other web sites so search would be useful.

F

Floyd

iTrader: (9)

This can happen...
http://bbs.scoobynet.co.uk/showthread.php?t=355358

F

Daz_WRX

so whats the best way of achieving a cold air intake?

Floyd

iTrader: (9)

YHM Daz

D4V3

Floyd, The cars a 94 WRX, it's fully de-catted and has a Z4 ECU. I've been contacting Adrian VOS to get hold of one of his chips with a JETEX panel filter.
I have a knocklink fitted and that seems to be OK.
I also have a bit of mesh at home waiting to be put infront of the pipe i fitted.

What else would i need to do to make the most of my DIY job.

Dave

Floyd

iTrader: (9)

It would be wise to get and AFR to check your fueling too. As for further mods it depends on how far your willing to go? Look at the whole induction path and think of ways that the hot bits can be seperated from the bits you need to be cold. Not sure on '94 cars but you could disconnect the water heating for the inlet manifold if it has it. You may find it under the throttle body. Insulating the manifold from the head is another mod but it involves a lot of work, but gives you more space for a front entry turbo and inlet... The header tank is a big sorce of heat IMHO and should be looked at also (if you touch the inlet manifold near the throttle body after a run and then move your finger to the header tank you'll see what I mean).

Have you changed the intercooler yet for a later model?

I don't have experience of the Jetex filter on a scoob (used one on a Vaux though) so can't advise there. Your mesh is a good idea to stop large debris but I don't know the size so can't comment on possible restriction to flow. Section off the offside area of the engine bay where the filter and ABS gubbins are, from the rest of the engine bay. This is a cheap mod in the terms of materials (aluminium etc) but will take time and effort to build.

All these little mods will add up and give you the result you're after hopefully. There are websites that detail all these mods and more, which will be worth searching for(Autospeed, Chairk etc).

F

D4V3

Cheers matie, I have a lambdalink at home which is also waiting to go on, Not quite sure how to fit yet but will be attempting soon.
I was thinking about insulating quite a few parts but haven't worked out what bits yet.
A bigger intercooler is on the mods to buy list but money situ isn't that good at the mo so it will have to wait.

beario

the problem with my cold air kit has been fixed,i refited the box that sits between the turbo and maf sensor,fitted the pipes back into it and now its fine..and there is still a noticeable improvement,for a basically free mod i would say its worth it.. but opinions obviously vary on this site..nigel

Aztec Performance Ltd

iTrader: (234)

I felt and measured it using g-tech.

Why thank you for the education

Wasnt the OE sucking in this warm air anyway?

Surely the key here is the there is more positve air being fed than before...particuarly when your moving (ie accelerating)?

At which point did I say 'my mate said'...or it made the car go really fast' The person in fact is has very much experience in his own Subaru rally cars. He didn't tell me to do the mod to make my car go faster...he just commented that it would improve the breathing (which it does) as with rallying the do what they can with some OE parts as they have to keep it on the cars to remain within specs.

I suppose this isn't a public forum where people can discuss imporvements etc that they've made to their cars without first clearing it with yourself

I suppose induction kits aren't as good as the OE box either!? :snooze:

The simple fact of the matter is I have done the mod already and yes it works far better than the OE system. I have already commented on ecu ability to cope in previous post.

I assume your not willing to put your money where your mouth is then regarding RR results?

Bob

Daz_WRX

Bob, have you ever had an induction kit fitted to your scoob? I have a HKS one on mine and its getting hot, so not sure whether to fit a heat shield or do your mod, how would you compare your mod to an induction kit?

Cheers

Aztec Performance Ltd

iTrader: (234)

Never had an induction as I always thought (like an idiot) that the OE system was good as it drew in cold air from wing...also plenty of sceptics on here about the use of induction...scared me away from trying it.


Have you done the following:

Remove undertray (big plastic cover under the engine bay)
Remove bonnet rubber
I assume you remove the resonator air box from the wing when you fitted induction?

You could look at the following...channel cold air from wing directly onto induction filter...

...Extend the induction pipework and place the filter in the wing...
...small bonnet scoop to feed cold air to filter...

...protect the filter from heat by constructing a cold air area near the induction.

Bob

Aztec Performance Ltd

iTrader: (234)

Oh and I've not had problems with mine with filter getting hot etc....all the openings in the airbox only face the direction of the airflowtake air from the front ie OE hole feeding off the wing...holes on front and front underside ...the rest of it is still the same as OE.

Basically you have to try to protect the filter as much as poss from heat whilst encouraging as much cold aiflow to it.

Bob

Daz_WRX

i will do now, i too thought the piping behind the head light was feeding cold air, will probably duct a cold air feed and fit a scoop, or even put the filter in the wing, i was looking at APS front mounts and APS reccomend putting it in the wing they sell a kit, not sure how much it is though

Floyd

iTrader: (9)

BOB

So you tested this mod on the ‘G-Tech’ meter? How do I know that you didn’t test the car at lunchtime before the mod and then retest in the evening after you mods? Or indeed on different days – with different ambient temperatures??? You did measure the temps didn’t you??? Was it the same road?? Same batch of fuel?? I suspect it would be very hard to get accurate test results on the road for comparative tests do to the many variables involved.

So now you want to do before and after tests on a RR? With the bonnet up or down? Mod first or second? You really want to spend £50 – £ 60 to prove a point? To gain a few horse power? I’d bet that most of any gain could be attributed to de-restricting the flow by removal of the resonator, rather than the extra cold dense air.

I’m not dismissing you mod but the way you presented it. I agree with some of the theory but I disliked the approach in the way you shared of the information IMHO.

F
PS If you remove the undertray, remember to remove the gear box cover or air speed will do it for you. Oh and this will also cost you in economy and top speed - a lot in some cases.
If you add a small scoop make sure you don't create a chimney effect when at a standstill or the temps in this area will soar.
IMO only remove the leading edge rubber in summer as it'll not be needed in winter.