thedeez

What has been everyone's experience with Magnaflow's cat back system, especially from a drone standpoint? The car I just bought (93 standard coupe) has axle back quad tip magnaflow on it. Been thinking of adding the mag. Tru-x muffler to replace the factory resonator. I added an h-pipe just after the axle which help bring the drone down some (1100-1400 rpm) . Still a little more drone than I like.

1984Z51auto

One of the contributors to drone is the position of the exhaust outlet vs the end of the rear bumper panel. If your outlets are not extended behind the bumper panel cutouts by an inch or so, it seems to amplify the drone. It is really noticeable on the early C4s with the round tail light rear ends, but impacts the later models also. Extending the outlets can make a real difference.

tgurnick

^^^

That's what I came here to say. I've got long tubes back to Flowmaster Super 40's. With no tips they exited under the bumper. The car was very loud and had a terrible drone. Once I got my tips on they exit (a bit too far) after the rear bumper. The car is much quieter in the cab while retaining a good sound and eliminated mostly all drone.

thedeez

Thanks for the input! I just bought the Magnaflow muffler/resonator that is used on their cat back system ( which with my already installed rear system effectivey now will be a cat back system) It will also allow me to move the tips farther rearward ( right now they are only about 1/2" past the bumper. Ill let everyone know the results after this weekend!