mrdeli

I am lucky enough to be awaiting delivery of a new Sti V 7, due for delivery in June. I am keen to uprate the power a little, but want to keep things fairly sensible, and mainly keep to fairly standard noise levels. Can anyone recommend an exhaust system? Also if I decat, is that just a matter of replacing the Cats with pipe, or do the cats act as silencers also? What power gains am I likely to get?

Many thanks for all who can help

TonyBurns

iTrader: (3)

There seems to be some boost spike probs with totally decatting STI7's but you can remove the rear 2 quite easily and not suffer any probs
Power wise, your probably going to be pushing the car to around 280ish bhp so will feel more lively, back into its proper territory
Watch out for some induction kits though, the MAF sensors are very sensitive nowerdays and some kits leave a gooey residue that can naff them up
Exhaust wise thou, you can fit a baffle box in your system but most probably still want a deeper sound, it will be bearable as ive heard an STI7 type uk with 2 cats removed, sounds better and picks up alot earlier
Check out either www.scoobymania.co.uk or www.scoobysport for exhausts, also jap innovations do one which sounds good but no price on that one though.

Tony

chrisp

I have an MY00 and have left the DP cat alone. It menas it will pass an MOT with no hassle. The new models seem more senstive to decats I would just replace centre and back box and see how you go. You can always do the rest later if you want. I have TSL centre and scoobysport BB and it sounds purposeful to say the least and feels spot on .

KenG

Tony, surely our UK STI's only have 2 cats anyway (confirmed a while back), so removing 2 is a total de-cat. Or am I missing something?

Ken

chrisp

Yep just had a look in the UK STI spec guide it says multipoint fuel injection with 2 stage catalytic converter. The wrxs have three though

Dave T-S

See here:

http://www.scoobynet.co.uk/bbs/threa...threadid=80851

The Sti has a four piece system - downpipe with cat, two piece centre one of which has a second cat in, backbox.

Unlike the WRX that has a cat in the up-pipe, it has a plain up pipe but this sleeved down with an internal sliding expansion joint.

Tread VERY carefully as per the comments in the spike thread. Our boost gauges arrived today so will get Carolyn's installed tomorrow and check what boost it is running with an open up pipe, OEM downpipe, and ScoobySport centre/backbox.

cico

Tony,
what boost problems are you talking about?

Dave T-S

cico
Read the thread highlighted in my post above.