Up pipe down pipe...whats it all about?

Which should i get first? do i need a downpipe if im getting a turbo back exhaust?

and finally 2.5" or 3" exhaust/uppipe/downpipe

Any help appreciated

stevie

 

if your going turbo back then you will need to get a decat down pipe, (dnt quote me) but i think they are 3" tapering down to 2.5" to fit your standard pipes,thats if your going to stick to the standard size exhaust, or go for a 3" all the way through.also if you are going to get a full decat system then a remap will be recomended i would think

 

If you are getting a new exhaust turbo back then yes,
Your down pipe is your fist pipe off your turbo. Then next question for you is cat or de-cat, my advice is de-cat (gasses flow better).
As for your up pipe, this is the first pipe to your turbo off your headers (manifold)
So for best results you will want a de-cat up pipe, then de-cat down pipe, de-cat centre section then back box of your choice(how loud you want)
All in 3"

 

what model and year ?
what power are wanting/running ?

exhaust- if below 370 bhp 2.5 inch is fine
decat down pipe- makes no noticeable power difference to a sports cat (eg prodrive), and aren't m.o.t friendly.

up pipe- if your car is wrx 2002 on, it will have a cat in it , if its a sti or earlier than 2002 it won't.

i wouldn't change unless, it has cat in it, then go for a sti one or a magnex with 40mm diameter bore, for good turbo spool up.

 

its a 2004 STI PPP.

So i need a decat up pipe 3"

and a 3" turbo back exhaust, 100 cel cat maybe?

Wantin about 350 -400 eventually

 

Yes mate
Plus a re-map then you will start to get close to 350 bhp.
But for 400 bhp you will want something like a AFP5-20 or a tdo5-20g with supporting mods

 

No you don't need a decat up pipe 3" as the STi up pipe doesn't have a cat in it

As for the rest i'd go 3" turbo back, 100 cel cat in the downpipe will save any hassle at MOT times

 

OK thats great. Thanks for all your advice guys

 

Hello mate, there's a group buy on Hayward & Scott exhausts at the moment:

https://www.scoobynet.com/group-buys...ll-models.html

A full 3" system (no CAT) is £460 + VAT.

Cheers

Anders

 

mmmm group buy sounds great. Thanks again