Hi
I have just bought a 2001 JDM Wrx Bugeye which has a 3" decat exhaust system but the standard airfilter. Will I see a performance gain by fitting an after marker airfilter, if so what should I go for ie panel type, mushroom instead of the airbox or an induction kit etc and which brand ?

 

K&N or Green Cotton panel filter.
The standard airbox is good to 400bhp

 

Subaru actually did quite a few bits right when they launched the bugeye........one of those was the induction side of things

A good panel filter will see you right (see above) unless you want all the noises, cold air feed, heatshield and re-mapping required for an induction kit LOL

Shaun

 

Another recommendation for the K+N panel filter. I,ve used them on all of my Imprezas(5) with no probs. Steve.

 

No gain after fitting Cone/Mushroom without the remap,and after remap you will loose bhp(with some cone filters),yes you can gain,but just marginal difference not massive claimed 15bhp.
Best bet is panel filter as K&N or Green Cotton panel Filter.



Jura

 

A induction kit will also upset the maf sensor so unless fitting a FMIC which means losing the airbox stick to a panel filter. If you want some of the noise I remeber seeing years ago a resonator delete pipe. This would remove the plastic chamber inside the wing and connect the airbox to the air inlet pipe.

 

K&N here as well. Got one in my bugeye running 340bhp.

 

Thanks for the replies, i've ordered a green cotton via ebay.

Forgot to ask - Is there a performance difference between a WRX and STi intercooler's, size etc?

 

WRX intercooler rated safely upto around 330 bhp, STI to around 380bhp.
STI one has a bigger surface area and depper core. Oh and red paint shouting STI

 

I was quiet surprised but defiantly worth looking at http://www.mkiv.com/techarticles/filters_test/2/

 

Those tests results do not relate to an Impreza . While power gains may be achieved by fitting a cone filter to a Supra, the same is not true of mildly tuned Imprezas, where cones have been known to reduce power and damage MAFs.

 

But no matter what car there on surly it's goin to filter the same and still have the same result. The out come of how clean and how they filter will b there same cos there manufactured the same regardless of what there fitted too surely

 

I agree with cones mess up the maf but I was surprised on the fact that the likes of hks which r considered by some as best in the bis. Actualy was the worst

 

On early cars the vibration from the cone wrecked the MAF as it was a bit fragile. Things improved for the newage MAFS as they were a lot tougher, the problem comes with airflow changes which need to have the MAF re-scaled in the ECU.

Shaun

 

The main issue with a cone filter on an impreza is it's locality to the turbo. Youve got 800 degrees of turbo heating up all the air around a cone filter which is then sucked into the engine . As we know engines like COLD air, hence all the effort Subaru went to to enclose the filter in a box and have cold air fed directly to it from the front of the car.

Stay clear of cone filters. Either replace with a good panel filter or spend the money on a good enclosed cold air induction kit.