sparky113

iTrader: (2)

Hi all,
in the process of sorting out the exhaust system on my 02 wrx. is the standard STI Downpipe an upgrade to the standard WRX Downpipe?

Midlife......

iTrader: (2)

Assuming there is no PPP fitted the Bug STI and WRX sysyems are the same apart from the up-pipe. The WRX has a pre-cat and EGT sensor in the up-pipe whilst the STi up-pipe is simply a pipe.

Shaun

sparky113

iTrader: (2)

Cheers for that mate, I ring be buying thaty downpipe then lol

Midlife......

iTrader: (2)

Filey.......... blimey that's one of my old stomping grounds from the 1970's I was born and brought up in Hull

Shaun

s70rjw

iTrader: (2)

You'll need the EGT warning light removing either during your remap, or fitting a 2.2K ohm resistor where the EGT plugged in to the wiring loom. Decatted up pipe will improve the turbos spool up

sparky113

iTrader: (2)

oh right ok then, well im just trying to source bits before i remap it, but at the mo the exhaust is blowing a bit on the downpipe so its annoying but i cant see the point in taking it off to sort it only to put a sport cat on in the near future. what ya think?

s70rjw

iTrader: (2)

If you change the downpipe, you really should remap straight away. If you can bare it as it is, change it once for good for your sport cat

Midlife......

iTrader: (2)

TBH you can de-cat and mess about generally with the UK bug WRX and have no problems.........the DENSO ECU is pretty clever and simply adjusts fuel / timing etc to compensate for the changes.

The good thing is that it gives a bit better spool up the down side is that because the ECU is so good it simply compensates for the change and doesn't really give any benefit in terms of better BHP, after all the ECU simply chugs along thinking its a 215PS bugeye LOL

Come re-map time things do get better

Shaun

PS de-catting the bug STi without a re-map can cause problems because of the bigger turbo !

sparky113

iTrader: (2)

thanks for the info mate, i will bear that in mind cos its starting to do my head in now with it blowing it also pops a little where its blowing so i wanna get it sorted. am i best to put sport cat in down pipe then de cat 2nd cat for decat downpipe then sport cat in second pipe?
also do you still get more noise when sport cat in down pipe and decat second cat?
sorry for all the newb questions i have gone from a 1.4mg zr to a scoob so its a pretty steep learning curve!!

Norman Dog

iTrader: (1)

Buy this, they are very good and will pass MOT no probs.
https://www.scoobynet.com/private-fo...ports-cat.html

Believe me, that is a hell of a good price too, I paid £260 for mine.

Midlife......

iTrader: (2)

It depends on how MOT friendly you want to be. ;D

The usual route to pass the MOT is to buy a sports cat for the down pipe, ditch the last cat but keep the up-pipe cat (the TD04 won't flow enough to warrant changing).

If you buy a bigger turbo then it's usual to port the headers and buy a new matching up-pipe.

For now though I'd stick with a sports cat and a "cat back exhaust" of your choice.

The one above mentioned by Norman dog is an absolute bargain ........

Shaun