gareth

I'm contemplating adding a decat centre section or downpipe to my PPP'd MY01. As price is roughly the same, which would be most beneficial? Any risks? Thinking of a Scoobysport item...

Thanks,
Gareth

tezza

Gareth
PPP already has a de-cat centre as part of the kit, so get a downpipe. But Scoobysport and others seem to say that an up-pipe is advisable as well to lower the back pressure and make it safer.
I had PPP, down-pipe, up-pipe and also changed the centre muffler and found this was much better, than just PPP only.
The only other thing would be to get a device to stop the engine check light coming on from Power Station or Scoobysport.
Terry

Dave T-S

Take care with putting a decat up pipe on a MY01 as I have been told of a number of lower up pipe gaskets blowing due, it seems, to distorted or misaligned replacement up pipe flanges.

Also had a blown gasket with a replacement up pipe after 2500 miles on Carolyn's STi7 (same pipe as the WRX).

Also, as RB5Scott discovered, if you *don't* fit the up pipe with a PPP and a turbo back decat, the ECU is really on the edge ignition wise.

Catch 22......

gareth

Thanks - I'm a bit of a newbie with all this (that's why I "forgot" my PPP already had a decat centre!). Dave - I don't really understand your last comment about ignition... any chance you could spell it out a bit more for me?

Cheers,
Gareth

Dave T-S

Possibly best email Scott and get it from the horses mouth

The ECU map only has X amount of ignition advance and retard built in to it. Once a given situation requires more advance or retard than the ECU can give then you have a potential problem.

For instance, if there is too much ignition advance and the ECU can't back it off this will cause pre ignition (or detonation) and this is probably the number one killer of Impreza engines apart from No. 3 big end failures.

Mark (R19KET) is also far better qualified on this subject than me.

[Edited by Dave T-S - 4/21/2002 12:28:54 PM]