Hi
I had a cold air induction kit, with pod filter fitted to my MY01 WRX. I never had it on a dyno, but the "real life" improvements were huge (easily comparable to decatting the exhaust).

I kept the system when I bought the STi 7.
Fitted it yesterday. And...the car felt slower! Boost only held to 0.8 bar...the punch in the back from 4000 rpm was gone...it really felt like the car was down on performance.

Refitted the OE airbox immediately.

Why would this be? It worked perfectly well on the WRX...but instead of helping the STi, it seemed to choke it...

 

I'm tempted to say "hot air ingestion"...

What does your pod filter / CAI look like?

 

It's basically a pipe that relocates the pod airfilter to inside the wheel arch. So there's no/little hot air involved.
And it worked perfectly fine on the WRX (during the summer). It is now winter here and damn cold, so temperature doesn't come into play.

 

maybe the filter is to small for the STI? restricting the air flow. just a thought
mike

 

Nope.
The STi has the same OE airbox and filter as the WRX.
So, there shouldn't be a problem there -what works for the one should work for the other?

Maybe the car gets too much air. Then, knowing it will be/is running lean, it limits the boost? Do you think the VVT might play a role?

 

Oh diddly doo!
Maybe if I went through the trouble of resetting the ECU things might have been different...

 

.8bar is likely to be the ecu initiating limp-home mode (if same as classic cars) - check for stored error codes.

Richard

 

Refitted the Oe box without reset, all fine now.