greatwhite

I have obtained a dowpipe off a 2003 STI, the downpipe has a blanking flage at the turbo end that blanks off the wastegate, my one(2003 STI PPP) has a small pipe running from the wastegate into the downpipe.

If I fit this what effect will it have?

And why do they fit both types to STI's?

360ste

iTrader: (1)

Fitting the new downpipe will cause problems as the gases coming fromthe wastegate will disrupt the gasses coming out of the turbine. Thus resulting in a loss of performance.

greatwhite

So why are they fitted to STI's with higher performace than std WRX??

greatwhite

found this post which contradicts this??
https://www.scoobynet.com/general-te...+off+wastegate

360ste

iTrader: (1)

Your car is currently running the PPP package which is a new exhaust including the downpipe. As standard it would have had the same pipe as you are asking about. My bugeye did until I had a APS system fitted.

360ste

iTrader: (1)

I suppose it is a case of one persons view and another persons view. Without back to back test on a rolling road I am not going to doubt anybody at first glance. All you can do then is try it and see what you think. Keep us posted, steve

greatwhite

I have taken the guts out of the cat, so I might try it and see what the difference is, if any

Tuts

I would think hardly any. I doubt you would notice. You currently have a ppp downpipe which has a sports cat in it. If you have taken the cat guts out of the standard sti downpipe and are going to swap them you will have a decat downpipe. I think this is what you are doing yes?

The ppp sports cat flows pretty much the same as a decat with the bonus of passing mots. If you have decatted the rest of the system I'd leave the ppp downpipe in. You won't gain anything by swapping it.

Chris