NOSLO6

The passenger side NPP/bi-mode muffler on my C6 failed after about 4,000 miles after an HPDE. I had it replaced under warranty for a failed internal baffle (loud buzzing noise under throttle, clanking at idle). After another 3,000 miles this new passenger-side muffler failed, again after an HPDE.

I run with the exhaust valves in the full-open position during HPDEs and have a mildly modified C6, but nothing that I can connect to the mufflers. No incidents of any kind at either event, not jumping kerbing, etc...

A post & search in the general C6 forum suggests that this type of failure is not a widespread issue. Could be coincidence, but 2 failures both on the same side has me wondering a little. Anyone here ever see this or have any thoughts?

Given that my warranty will be up soon, I'm not encouraged about the longer term given the cost of these mufflers once my warranty is up. The dealer kept the first one, but I'll be sure to try to get the 2nd one back, cut it open and see exactly where the failure occurred and see if I can't weld it back together.

Thanks.

davidfarmer

considering the popularity of the muffler-mod for the C6Z06, it should be easy enough to open the muffler and repack it if that's the problem. Personally, the bi-mode exhaust is a gimmick I wish GM would get rid of. I'd much rather have a lightweight Corsa that is both quiet AND hi-flowing, instead of the muffler that GM builds.

AU N EGL

I agree with David. Get rid of the bi-mode gimmick.

NOSLO6

Mostly curious about the cause / failure point and any relation to HPDEs since this one will be a warranty replacement. I suppose I'll find out if I'm able to beg the old one back from the dealer and cut it open.

Spending money on any muffler, Corsa, GM, or otherwise isn't at the top of my bang-for-the-buck list! As David notes, easy to weld them back up, but I'm just curious. Thanks to all for the feedback.

C5Lion

I think this is what is going on with my car. I was not sure what it was but it sounds like what you described above.

My car now has a loud drone sound most notible in 4th, 5th and 6th gears when I accelerate from 1500 to 2000 RPM. This happened to start on the ride home after a track event.

I also now notice a rattling noise when the car is sitting at idle.

My car is out of warranty so I am not sure what to do. I can pretty much drive around this noise but it is annoying.

How much are these mufflers to replace? I was thinking of just getting an after market exhaust.

Bill Dearborn

Why bother replacing them. Do like the people that do the Z06 exhaust mod. Have them cut open and instead of blocking off a pipe have the material that is rattling taken out. Cheaper to do and probably more satisfying over the long run.

Bill

C5Lion

If I do that, are they going to sound OK or have that annoying drone at cruising speeds?

NOSLO6

They will sound like new-- the re-weld would fix the problem, which is a broken weld on one of the baffles. If you open them up I'd add some additional strength to the other welds too.

There's a thread in C6 tech that talks about this issue as well. Thanks to the folks here who have posted.