Premuffler vs cat

[cjannelli]

I recently installed an M&K GT3 muffler on my 87 Carrera. I left the catalytic converter in place.
Can anyone weigh in on the effect of replacing the cat w/ a pre-muffler?
Chris

[RarlyL8]

Performance and sound both increase with the pre-muffler.

[Joe6pack]

I replaced the cat on my '87 with a premuffler and it really improved the throttle response. I also run without an O2 sensor. Overall the car is much peppier and the sound has improved. Just make sure you are in proper tune. I use an LM-2 for setting the proper air/fuel ratio.

[Arne2]

Chris, I have the pre-muffler on my '84 with the stock banana muffler. Even with the stock muffler on it, I find the sound is pretty nice. Mine pulls very hard to the rev-limiter, but I do have a Steve Wong chip tuned for the pre-muffler.

[DG624]

I did the premuffler with Steve Wong chip and it works great above 3,000RPM. Not loud at regular driving ranges. The premuffler also reduces about 13 lbs and if you drop the heat shields another 7-10lbs (ceramic coating for premuffler to reduce heat). I kept the CAT for non-racing.

[quattrorunner]

I have a premuffler in case anyone wants it. $40.00 plus ship?

[sm70911]

PM sent

[magnumpi]

Guys, will an SC run richer or leaner without a cat and with the premuffler or cat delete pipe w/sport exhaust? So we need to richen or lean out the mixture?

[Joe Bob]

Depends on how it was running before....either way it needs an exhaust analyzer to diagnose and adjust.

BTW, the word is with a pipe replacing your cat you will likely get visual smoke.

[Busta Rib]

I have a pre-muffler for sale: FS: OEM Euro 911 Pre Muffler (no O2 bung)

[Arne2]

Originally Posted by Joe Bob

BTW, the word is with a pipe replacing your cat you will likely get visual smoke.

Not necessarily. I have no visible smoke from my car.

[Joe Bob]

Don't shoot the messenger...I don't have a catless motor.

However there are many that do and have aftermarket chips and kvetch about smoke.....