exhaust problems?

[naturalskillz]

I have a 95 neon and the check engin light keeps coming on saying that the Cat is bad. It was replaced with a high flow one months ago. I had a exhaust on it from the previous owner. I had to replace it bc it was tearing off at the factory weld. I put a APC exhaust on it from a v6 bretta. Is the problem, too much flow and not enough bach pressure. Also what would be a good replacement for the exhaust that i have on now? Was thinking a borla or pacesteer, would be good.

[-=God-IM-Secksy=-]

my moms car was almost the same thing when my brother put something like that in try takeing it to the shop and getting it tested

[lilblackneonrt]

good replacement muffler would be the fattest hpr muffler, everyone likes flowmaster pacesetter and all that bull crap. I have no cat and an hpr muffler and it sounds good as hell. That muffler took all the high pitch almost like pinging noise away now its a low deep tone. thats what i recommend.

[naturalskillz]

The exhaust that i put on there, is really large. I have a deep sound from the exhaust but when i'm at at really high RPM's and shift i get that rice sound. my old exhaust never did that.

[Scatch!]

There is a common misconception that backpressure is needed, but it isn't. At all. What happens with an exhaust that is too large is that exhaust pulses slow down too much before they exit the pipe, causing a "train wreck" of sorts, which actually increases backpressure. It may be that you do indeed have an exhaust that is too large for your car and isn't scavenging exhaust well.

That's a terribly over-simplified explanation, but it'll have to do for now.