I've had a centre cat replacement pipe on my sti7 for a couple of months,but recently the car has seemed very sluggish at low revs,
so on wednesday I put the cat back on to see if it made a difference,first test drive the car seemed about the same but as
the week has passed the car has got faster and faster and is once
again a joy to drive.With the cat off I was seeing an extra 0.2bar
boost spike,is it possible the ecu was seeing this and pulling
the timing back? or does any reduction in back pressure destroy the low down torque.
steve.