afterfire or backfire?

gleonard · 12-29-2009, 08:26 PM

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.

gpa7pk · 12-29-2009, 08:45 PM

subscribed

kannibul · 12-29-2009, 09:00 PM

Quote:

Originally Posted by gleonard

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.

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.

F.I. Inc. · 12-29-2009, 09:33 PM

Quote:

Originally Posted by gleonard

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.

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

gleonard · 12-29-2009, 09:47 PM

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.

ChrisSlicks · 12-29-2009, 11:18 PM

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

12-29-2009, 11:21 PM

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?

gleonard · 12-30-2009, 03:55 AM

Quote:

Originally Posted by ChrisSlicks

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

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.

Rob@Altered · 12-30-2009, 09:30 AM

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.

m4a1mustang · 12-30-2009, 10:05 AM

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

370Zsteve · 12-30-2009, 10:11 AM

Quote:

Originally Posted by kannibul

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.

Exactly.

spearfish25 · 12-30-2009, 10:24 AM

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.

darkROAM_1 · 12-30-2009, 11:03 AM

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.

DJ_TJ · 12-30-2009, 11:26 AM

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.

Modshack · 12-30-2009, 04:44 PM

Quote:

Originally Posted by spearfish25

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.

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

12-29-2009, 08:26 PM	#1 (permalink)
gleonard Base Member Join Date: Jul 2009 Location: Los Angeles Posts: 196 Drives: 370z Touring/Spt 6sp Rep Power: 16	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. __________________

12-29-2009, 09:47 PM	#5 (permalink)
gleonard Base Member Join Date: Jul 2009 Location: Los Angeles Posts: 196 Drives: 370z Touring/Spt 6sp Rep Power: 16	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. __________________

12-30-2009, 09:30 AM	#9 (permalink)
Rob@Altered Enthusiast Member Join Date: Jul 2009 Location: Gaithersburg Posts: 282 Drives: 350Z/370Z/GTR/G35 Rep Power: 369	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. __________________ Altered Atmosphere Motorsports RobS@alteredatmosphere.com

12-30-2009, 10:05 AM	#10 (permalink)
m4a1mustang A True Z Fanatic Join Date: Feb 2009 Location: Northern VA Posts: 55,385 Drives: on two wheels Rep Power: 6962	Yeah, that's totally normal. A little popping and gurgling when you are off throttle... sounds mean. __________________ - Steve Zs & Coffee - Saturdays at 10AM in Fairfax, VA and Columbia, MD (Click the banner!) LIKE us on Facebook!

12-30-2009, 10:24 AM	#12 (permalink)
spearfish25 A True Z Fanatic Join Date: Mar 2009 Location: Naples, FL Posts: 4,117 Drives: to work Rep Power: 1856	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. __________________ 2013 Cadillac V-Wagon, RIP Z

12-29-2009, 08:45 PM	#2 (permalink)
gpa7pk Base Member Join Date: Apr 2009 Location: Texas Posts: 135 Drives: 1959 Triumph TR3A Rep Power: 16	subscribed

12-29-2009, 11:18 PM	#6 (permalink)
ChrisSlicks A True Z Fanatic Join Date: Mar 2009 Location: North East Posts: 6,203 Drives: 09 370Z Sport M6 Rep Power: 653	The noise you are talking about is there stock, just very muffled. I like the noise, it sounds cool. How loud is it?

12-29-2009, 11:21 PM	#7 (permalink)
blue660r01 Guest Posts: n/a	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?

12-30-2009, 11:03 AM	#13 (permalink)
darkROAM_1 Base Member Join Date: Nov 2009 Location: Oak Cliff Posts: 78 Drives: 09 MB 370 base/sport Rep Power: 16	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.

12-30-2009, 11:26 AM	#14 (permalink)
DJ_TJ Base Member Join Date: Nov 2009 Location: soul cal Posts: 29 Drives: 09 nismo #0097 Rep Power: 16	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.