Is anybody here experiencing exhaust backfires with there Cobalt SS/SC ?

 

It happens now and again. It's normal. My especially with a straight thru exhaust

 

Its probably my favorite sound ever.

 

What you're hearing is not a backfire. It's just a popping sound that you sometimes get with a very free-flowing exhaust. You hear it especially when you let off the throttle, right? When you let off the throttle, there's a sudden drop in pressure in the exhaust, which causes the popping noise.

I'm not saying all this to be a dick, but because 'backfiring' is a pretty bad thing, whereas what your car is doing is totally harmless, and in fact most high-performance cars do it. Don't worry about it .. nothing's wrong.

 

I was gonna bring it to the dealership for them to have a look at it. I read stories about unburned gaz blowing up Muffler baffles, Cat converters. Am gonna stop worrying about it
for now.

 

Well there's a couple things here. What you're talking about is called afterfiring. Afterfiring is when fuel left unburnt is ejected into the exhaust and ignites in the exhaust, after combustion has taken place in the cylinder. Backfiring is when fuel somehow makes its way back into the intake tract, and ignites in the intake.

You have to be pretty rich to have afterfiring. If that were happening, you would certainly have a Check Engine light on, because the computer would detect that something isn't right.

You have to have something VERY wrong to backfire into the intake tract. Like timing messed way up, something broken, etc...

 

i love that noise

 

be carfull, you can also blow out those miffler bearings real fast.

 

I hear some owners complaining about "detonation" in their exhausts. How does this differ from "afterfiring"?

 

They're referring to the same thing (afterfiring - unburnt fuel lighting up in the exhaust). Just using the incorrect terminology.

However, I would bet you dollars to donuts that NOONE is actually experiencing afterfiring. What they're hearing is the same thing denny is talking about - a slight popping noise caused by sudden pressure drop in a high performance exhaust. It's perfectly normal, and nothing whatsoever is wrong. Download some video clips of high performance vehicles .. anything with a free flowing exhaust will make that popping noise much worse than a Cobalt does.

Believe me, if you were running so rich that you're lighting up your exhaust, you would certainly have a Check Engine light on by now. The computer would detect that. If you're really worried about it, though, by all means take it to a dealer, have them hook up a scanner, and they'll be able to tell you that it's not running too rich. If you just don't like the sound, consider changing your exhaust ... a different type of muffler or some smaller pipes can clear that right up, although maybe at the cost of a couple horsepower....

 

Thank you DanM for shedding some light into this matter. I have to admit, the popping noise does sound better now that its not destroying anything. Now we know the SS is equipped with a nice free flowing exhaust setup. That would mean we wont benefit too much by bolting on an aftermarket exhaust.

 

I wouldn't necessarily jump to that conclusion. That's probably my fault for oversimplifying - the popping is "generally" caused by a more free flowing exhaust, but that does not mean that the exhaust is the absolute best it can be. There still may be room for improvement. Or the popping could just be caused by something in the design (some particular tube shape or size or orentation, or the shape or size of the muffler causes something to resonate or pop or whatever... lots of physics that I don't pretend to understand).

To that end, zinner had an exhaust done on his car (catback only), and he got 10hp out of it! So there may still be room for improvement. Not sure if his pops or sounds raspy though.

https://www.cobaltss.net/forums/2-0l-lsj-performance-tech-47/stainless-steel-catback-exhaust-3-0-inches-3567/

Edit: BTW, where you at, denny? I'm in Oshawa.

 

My car stopped making the popping/backfire sound after I had the muffler replaced under warranty. Did anyone else that needed a muffler also have this happen ?

 

you must not have ever heard the exhaust on an SRT-4 then..... cause man, somthins gotta be wrong wit that car!! LOL

 

Actually this is for debate. I truly believe that with a good CAI and bigger headers, the stock exhaust would be suffucient to handle. I think the header is the most restrictive part of the 2.0L engine. Adding aftermarket exhaust is "ideal", but not necessary for HP gain provided the CAI and header are installed properly.

 

Am in Ottawa.