Air Induction

D

dpsubaru

The Torque Meister
Points
192
Location
Scotland / Vietnam
Car
Subaru WRX Turbo 04
Hi, Have recently bought a 2004 WRX 2.0 Turbo model (non STi) recently, engine is standard, any pointers on where to start first for uprated power (brakes being dealt with already as they are a bit weak)?

Was thinking to start with changing the usual air filter for ram air (K&N or the like) - time is a problem so only simple upgrades to begin with, :confused:

Thanks
 
I'd say get the breathing right so match the induction kit with an exhaust. Make sure you have a cold air feed otherwise you will just be sucking warm air into the engine.

The standard intercoolers are not brilliant and you can see reasonable power gains from a sports intercooler, front mounted if you can but anything should be better than the standard one.
 
Small essay but should be a good little bit of advise ;)

Have no fear with the standard intercooler mate. They are fine if people know what to do with them. All you have to do is buy the seal that goes under the scoop which a is designed not to allow any air to pass over the sides of the intercooler and make it go through instead which gives emensly better cooling. Another one alot of people do is buy the bigger Bonnet Scoop from a Prodrive spec Scooby or an aftermarket one which is designed to catch more air. Again pretty good but the seal is 10 times better.

First off, don't bother with a K&N on a car like a scoob, get something that was made for it like Blitz or a HKS mushroom filter. Far better breathing capabilities than a K&N or Pipercros etc. You dont need to worry about the fitting of a cold air feed if you dont want to. Just make sure you have mounted away from the engine. A common solution is mounting the air filter inside the wing as the is a hole just big enough to fit the intake pipe in with the filer on the end. Or you can just mount the filter directly behind the headlight. I have done this and the filter doesn't draw any warm air in other than sitting at traffic lights when the whole engine bay warms up a tiny bit lol.

Then get the silencers/centre sections taken off the exhaust and have it made straight through. It's up to you what back box you have but just make sure it can flow correctly with the rest of the exhaust. These 2 alone should release at least 20 horse by themselves. Then think about a nice dump valve or blow off valve so you keep the turbo a little sweeter with changing gears and turbo lag etc. All finished off with a remap as you tend to need to remap these thing almost everytime you mod the engine, certainly if the mod is designed to gain say 20bhp+

All that should see you a good 35-45 depending of corse if yours is a Jap Spec or a UK spec ;)
 
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Thanks, any suggestions on the type of sports intercooler (i.e manufacturer) - are some better than others - looking for road performance only as regretfully no time to get to a track,
 
This was a similar route that mine was taken on, well at least the order things have been done anyway. Then with the bigger TD05 turbo (can be found on many of the more powerfull STANDARD scoobies so if you are willing this can be an easy and cost effective mod, just rememebr about the remaps) ;)

On the intercooler side of things. The nice chappy at this Scooby Tuning place actually filled me in on a helpfull bit of info. Intercooler dont actually make alot of difference to the performance on their own. They are designed to make the air cooler, there for when you have one fittted, you usually always have a remap and because of the extra cool air, the fuel ratio can be bumped up to match the extra oxygen intake, thats when you see 30bhp+ gains from them. I couldn't beleive it myself but sure enough, 3 tuning guides later and I was convinced lol. So i'm not bothering with one unitl I decide to take the car past 350bhp as shes running sweet as anything at the mo and coping with 315bhp all day long.

But if you are desperate to enlarge your intercooler, then I can offer yet another cost effective mod ;) Dont go for a front mounted unless you go for big BHP figures, but instead look at fitting a top mounted intercooler from one of the 2004 onward Scooby STi's. They are 1 third bigger than the standard WRX models and are good for 350bhp if used correctly. Or even from a 2003 Prodrive scooby ;)
 
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I have uk version and already working on the HKS induction filter - although seems that only teh Sonic one is readily available, the cheaper - but also most likley more popular one - is sold out. C'est la vie - seems will need to go with the Sonic as no time to wait for the other type to come back.

Due to my job only have 4 weeks a year - max - to mod and drive the car so try to have all parts waiting for when i get back and start immediately.
 
One other question i have is in regards to suspension, when going over a slight hole or dip in the road you can hear a slight clunk from the front suspension - i know someone else who has an STi of similar age with exactly the same problem as the only was to solve it is by change the suspension. So was thinking Eibach shocks and springs, but not coil overs as this will be too hard. Any suggestions on this one? (bilsteins are too pricey!)
 
What about Tein with electrically adjustable damping force? You can have a road and track setting fairly easily.

Eibachs are good as are Koni's. Are the bushes in good order? Uprate them to Poly bushes and your handling will be sharper.
 
Havent made a close inspection of the bushes but the car only has 11k on the clock, genuine miles, so dont expect much wear on these yet (well hopefully not - was hoping for a quick splash and dash suspension change, 4-5hours one afternoon). Are Tein's comparable cost wise with Eibachs/Konis?
 
Your best bet is really ringing around. Prices vary. The more business a dealer gives to one make the better their prices.

Don't forget our sponsors shop (who are having an Xmas promotion) http://torquecars.potn.com;)
 
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Thanks for the heads up on http://torquecars.potn.com, induction kit and dump valve now on the way - will let you know how it goes. Suspension is a whole other ballgame, seems very few actual kits, that are not coil overs, available, everything is separate and then the cost is almost the same as coilovers.

Can anyone advise what the ride is like with fully adjustable coil overs adjusted for about 50% max reduction in ride height - is the drive relatively smooth or very hard? Have had standard lowering kits on fords and ride was ok but on a previous Pug 205 Gti even the standard lowering was pretty hard. Thanks,
 
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I wouldn't do the air filter without doing the exhaust mate. You will most likely make the car run worse than before as it will be sucking in mor ethan it can get rid of. But yes, if you have a filer, dump valve and the exhaust done, then definatly have a remap ;)
 
Thanks, will look into this - but am trying to get something that looks (from the tailpipe point of view) similar to the original, unsuspecting.

One time before put an ashley system on an escort, no power difference but the sound was unbelievable!
 
No dont go for silly little twin exit things at all with a scoob. The hole idea of making the exhaust straight through is to get the flow of air better, so if you were to put a restrictive exhaust rather that a big bore, then you will still have different pressures throught the system. My system is 3" bore from the turbo, straight through to the back box which is a 5" tail pipe. The flow is near on perfect apart from me having the headers bored out.
 
Seems i'll need to wait on the dump valve as the ej205 engine (fitted on wrx turbo) isnt suitable forblitz - will check with others or if anyone knows what else will fit please let me know, thanks.
 
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