afterfire or backfire?
 

I recently had an aftermarket CBE installed (less than 30 days ago) and have recently noticed a muffled backfire/afterfire upon deceleration. I never hear it when I am hitting the throttle, and usually hear it when I let up on the gas to shift gears.

Is this caused by an exhaust leak? is the car running to rich? Is this normal, does anyone else have the same sound?

I contacted the company who I bought the exhaust from (they also did the install) but I haven't heard back from them yet. It's been a few days so I thought I would try to get an opinion from the experts on the forum.

Any help would be greatly appreciated.

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As far as I understand it, it's a backpressure pop. Most cars do it, just some you never hear it until you have the kind of exhaust that makes it audible.

Hey bud, sorry that I haven't gotten back to you. It has been very hectic since we got back from the long weekend. Since you are local and I did the install, I would like to hear it in person if you have time. It is not common but always a possibility that something could of loosened up. As a matter of fact, I will just give you a call right now...

Thanks, Tony

Hey Tony, thanks for getting back to me, I know everyone's busy with the holidays! I may try to swing by after New Years when things aren't so hectic so you can hear what I'm talking about. Like I said, it's not really an alarming sound, just want to make sure it isn't something that I need to worry about.

The noise you are talking about is there stock, just very muffled. I like the noise, it sounds cool. How loud is it?

When I installed TP's a while ago on my 350z it did this every so often. Does this occur frequently or is it a rare occasion?

it's not any louder than the rest of the exhaust note, it just sounds out of place. It goes from a growl to a gurgle back to a growl.

Yeah, it sounds like a normal thing that happens with modified exhausts. It happens on my car every once in a while. You only notice it now that your exhaust is modified and is a little bit louder now.

Yeah, that's totally normal. A little popping and gurgling when you are off throttle... sounds mean. :)

Exactly.

Enjoy the sound...that's my favorite part of any exhaust note. The TopGear guys call it 'runoff'. It's the sweet 'burble' you get when you lift the throttle and decelerate. When I did the muffler delete, it was f'ing awesome.

Heck, when I had my Slowica w/ it's Kazuma exhaust, I got backfires w/ actual visual flame pops. It only happened when hitting on the gas w/ a little load then immediately letting off the gas or pressing in the clutch. Since the car was in the process of accelerating, there was more un-combusted gas in the exhaust that would ignite there.

This is also due to the fact that I was running no cats at the time.

my fc used to shoot flames with racing beat's exhaust because it was running rich and no cats. after getting it tuned no more flames or popping noises.

Ah...The "burble"....Sure wish I had some with the Stillen... I used to love that on my Vette....