hey all, i have a 2002 sti type uk with ppp, at the min it has a full 3" turbo back exhaust and made 301.5 bhp on rollers.
now if i was to go back to a standard 2 1/2 system would i notice any power/torque drop?
cheers, shawn.

 

2.5" should have plenty of flow to cope with a 3" map at 300bhp.

edited:

Just noticed STANDARD 2.5 exhaust..not sure what the 2002 PPP came with cat wise.

If you re-introduce cat's into the equation you're prob loking at 20/20 imho

 

sorry, would be still going for a full decat just a 2 1/2" system. just wondered what the effect would be, want to keep it cat free just a bit less noise on a morning.

 

also looking at going the re map route soon, looking at about 340 ish on both. would 2 1/2 cope with this?
cheers.

 

I've always thought a 2.5" exhaust was plenty for up to 350...

 

IMO you would see a power drop. I remember a discussion about the Miltek 2.75" and 3" systems a fair while back. The 2.75" gave better torque but the 3" gave more bhp.

 

if your gonna have it remapped at the same time which would be my reccomendation then you wont have any power loss at all, but it would probably increase by around 30hp. i run a 2.5 at around 370

 

Hi Shaun, mine managed fine up to about 360 bhp, but I reckoned I'd need a 3" system to get 400 bhp.

dunx