well hung

Ive lost touch with scoobys after buying a cosworth but my brother has an 02 plate wrx and is thinking of fitting a downpipe. It currently has a wr sport back box with a centre de-cat. Can he just fit a down pipe on with the standard set up or will he need a re-map? Ive heard a few horror stories about over boosting and blown engines and dont know if their true or not. When i had my 99 uk turbo i had a magnex from the turbo without a resonated centre and only the back box and had no problems what so ever and ive heard the car is still going strong over 3 years later. Do later cars have this problem?
Cheers Adam.

rexabusa

depends what type downpipe you go for, i think the open neck are bad for spikeing- overboosting.
check out ebay for different neckers.

jaytc2003

iTrader: (1)

generally the cars are okay with out the remap, you will get better spool up and a better sound (did with my tsl grp a one anyway). A remap will always take advantage though of any mods carried out giving more power and better driveability, and usually fuel economy as well.

mgcvk

Remap will improve driveability and as above make the most of your mods. I find car has better fuel economy now after decat and remap, but obviously not when you are booting it

Ben WRX Bug-Eye

If you de-cat the downpipe you are increasing the chances of the engine running lean without a remap. This is because the turbo will boost higher without fueling setup to match.

If you then go and fit a performance panel filter, or worse still an induction kit, your asking for trouble really. I've removed the centre cat on mine with a performance panel filter, which I personally feel is as far as you can go while retaining a safe margin.

Scoobs do run slightly rich as standard and I am sure others will say that they run full decat's with no issues, but the thought of needing engine rebuild for me is extremely unpleasent.

jaytc2003

iTrader: (1)

Can only speak from experience, and mine was still running overly rich with the full decat and an apexi induction kit. It was only when I got the powerfc fitted and mapped that we knew just how rich it was running. Explains why I am now getting an extra 60 miles per tank with probably more hard driving.

The turbo in effect wont boost higher as the boost control still works the same, ie it will still open the wastegate at a predifined point, what you may get though is an occasional spike which may invoke the fuel cut, what it will do is spool up faster and generally react quicker

well hung

mmm.... Like i said before, i had no probs on my car when i fitted a downpipe but that was a classic shape. TSL have told my bro they would only fit a downpipe if he had it re mapped. Unless he buys the expensive one with the sports cat in the downpipe. Think he's not going to bother, very expensive rebuild if it goes wrong.

jaytc2003

iTrader: (1)

that is strange, I got mine from them and nothing was mentioned about a remap at the time, (although they did know I was getting in remapped a few weeks down the line anyway)
FWIW mine is a classic as well. Just get your bro to buy it and fit it himself, not a difficult job to do, and the nuts should still be relatively free on an 02. Mine is 10 years older and just used some penetrating spray before I started work and it was fine. Just set aside a few hours to go at a very steady pace

well hung

Cheers jay, for some reason the classic is ok to fit a downpipe straight on without mapping. The bug eyes onwards need to be mapped when fitting a downpipe apparently.