ScoobP1

iTrader: (1)

Is there any benefit in replacing the up pipe but retaining stock headers?

Cheers

DTVHSR

Not unless it's an 03-05 Wrx you have, it would also need mapped afterwards.

AS Performance

iTrader: (4)

i disagree a correctly matched and flowed up-pipe will give benefits but yes it does require mapped to gain the benefit

daveyj

iTrader: (1)

Will there be any problems/engine management lights thrown up running a decat up pipe, sports cat downpipe on a standard 03 WRX? I've been buying parts to fit to mine prior to a modest remap. Will obviously take it steady until said map is done.

ScoobP1

iTrader: (1)

Its a P1 I have so no cat on the up pipe. I will be getting it mapped as I will be using a different turbo and injectors on the new engine.

Are they more unreliable though for cracking than OE versions?

dave_t

iTrader: (1)

Nice thread steal lol.
You should not get any CEL errors (assuming you use a PPP downpipe), if you do the mapper should knock them out for you.
You mention a modest remap? If, like me, its sweet running you want rather than squeezing every last BHP why not leave the up-pipe/downpipe and just loose the centre cat (which was what i did). Racedynamix got 280 bhp on that (with filter/cat back). You would get maybe an extra 10 with the up-pipe/downpipe done, but to me didnt warrant the extra dollar...

dave_t

iTrader: (1)

I dont think that replacements are better quality (depending on what you buy).
You can get gains by matching/porting as said above, but very little.
My advice would be "if the car is in bits anyway think about replacing but match/port, if its not in pieces and not broken leave it alone"

MrNoisy

iTrader: (28)

Harvey up pipe will net you slightly improved spool and performance.
Having swapped it, I gained around 10bhp changing from an H&S up pipe to a Harvey one on stock headers and then having it mapped in.

AS Performance

iTrader: (4)

we manufacture & distribute the "harvey smith" trick up-pipes and (bearing in mind i might be slightly biased ) the quality is the best out there

we dont do "one size fits all" and will "match" your spec to a suitable offering

daveyj

iTrader: (1)

Seasoned forum *****

I've already got the items so it's not a problem. I was looking for around 270/280 which should keep the old girl reliable. I wanted to make the exhaust as efficient as possible prior to upping the boost. Have got everything already mentioned plus a 255l/h fuel pump and K&N panel filter.