Sorry for this old chestnut.

Just had a scoobysport backbox and downpipe fitted to a MY96 WRX. Wow. Cannot believe power difference. So much more torque, revs all the way eagerly to the redline. Amazing.

However, since having it done the turbo comes in at about 3000 instead of 4000. This is relevant as it is right just right for acceleration from 65ish in fifth gear.

The problem I dont think is the exhaust, it is just that the increase oral performance enables me to hear that the engine is not picking up when I floor it. It doesn't misfire just makes a rumbling sound. Dont think it is detonating, although I have not heard this, I am told that it is a distinct sound. The car feels almost as if it is trying to push out a blockage. I thinki it has probably always done this, and is more noticable when using 95 instead of 97 ron.

Any ideas would be greatly appreciated.

I was wondering if it might be overboost or something (although I dont know what this is, I know tat it is attributed to maximum boost under load, which this is)

Please help.

 

Could always pop over my way and I'll have a listen..got some good "fast-countryside" roads here, just have to make sure we don't meet dick grimes coming the opposite way (has happened)