Cajuncrawfishco

I have a 08 Z51 with D1 (tune done by Taylor DP) headers/hi flow cats and the stock (I believe) Z51 exhaust with M/W switch

Even after recent tune (I trust) car has that horrible "popping" (backfire) out of exhaust when baffles are open while decelerating.

Sounds like a "gun show" gone bad I did NOT buy a ticket to attend. You get the point. When I get pulled over........ cops may think I am dumping a clip on them.....

I want it gone and am not sure if it is a "cat" issue or I must go to different exhaust?

Just embarrassing when it backfires (thats what it sounds like) at very low speed while down shifting or worse just decelerating in gear.

Please help me leave the gun show behind........I live in Texas but would like to leave Bonanza behind.

What do I need to change to make it go away but do like M/W exhaust option.

Thanks

David

FloydSummerOf68

If you want it to go away, remove the headers. To lessen it just keep the baffles closed.

I've never heard a C6 with longtubes that didn't have some popping on deceleration with a free-flowing exhaust.

ktoonsez

Floyd is right, but if it is really that loud, there is probably some fueling issue's (nothing that can hurt the car but just makes the popping louder) in the tune in high RPM low MAP which can be corrected. Also could be the DFCO setting in the tune.

Cajuncrawfishco

"I've never heard a C6 with longtubes that didn't have some popping on deceleration with a free-flowing exhaust."

Perhaps I am just stuck with it then as headers are on for the long haul. Just curious but is this common on every other type of car with headers/free flowing exhaust? Did not think so?

Not arguing just wondering as I have never heard such "loud" popping (really sounds like fuel exploding on way out) with a car just because of type of exhaust I have.

I appreciate the feedback from any/all

Thanks

Cajuncrawfishco

I asked about tune but could double check again as it is that loud. Sounds like a 22 going off at times!


What is the DFCO part of the tune?

Thanks. I am currently at just under 670 rwhp and like set up but may have to get a few friends to hear popping who have same cars!

Thanks again

FloydSummerOf68

Just with a description it's hard to know if the popping is normal or excessive.

It's certainly possible that it's in the tune and that it could be reduced some.

My old 02 Fbody had the same situation.

ATC399

I love it when my LS3 pops/backfires on decel..No tune or headers

Cajuncrawfishco

Troller.........you can certainly have all of mine for free if I knew how to package the noise up and send it to you!

I suppose hard to describe the sound but saying it sounds like a 22 was fired is accurate. Turns heads and is so loud at times "lower rpms" it is quite the attention getter I venture to say people say something is wrong not right!

I gather only other thing to do is remove headers......or double check tune.

Hope there are some other ideas but issues sounds common and I guess I need to have some other owners I know hear mine and tell me if they think it is normal or not normal on the loudness of the popping

marc8090

Stock tune, no headers, open baffles on stock NPP exhaust and it pops alot on deceleration. It's normal.

FloydSummerOf68

If you give it just a little bit of gas on deceleration that will help even it out.

ktoonsez

DFCO is "deceleration fuel cut-off". When mine was enabled, meaning it cuts fuel going from mid-high throttle to no throttle, it did alot of popping. After disabling it, it is almost completely gone. Also had to adjust my VE (Volumetric effeciency) table to help it out. Could be a difference between our cars too. I have '08 vert with 1 7/8 kooks headers and only 420 HP compared to your 675.

Cajuncrawfishco

Thanks that addition of fuel and actually taking it out of gear eliminates it altogether but cant do this at every stop!

Slowed down near a school zone the other day all of the MOMS loved my car! They thought Johnny/Suzy were under attack.

Me......thought it was kind of entertaining.

Thanks for the feedback guys!

FloydSummerOf68

Well at least you have a partial solution

BoosterClub

ANY car with catless exhaust will pop and backfire when getting off the throttle or decelerating. Fuel overrun is the cause when it's normal, but there's things that could be happening like a leaky injector causing it to be worse then it should be.

Also, if your exhaust is not sealed well, you have a vacuum leak or things of this nature that allow air in, the backfiring will be worse.

White_Lightning

DAve its part of Long tubes/no cats/highflow cats on a V8. the popping is small amounts of unspent fuel popping in the exhaust. It happens stock too, just is SO quiet you dont hear it thats part of owning a Big V8 as a matter of fact i make sure mine is open and pops every time i drive past some one in a prius

Wait till you blow flames out the back on a 7k 3-4 shift

HC Mechanic

That's what I'm talking about

Cajuncrawfishco

Meth on car with D1 I hear its blue flames so here they come..........

glenB

I hope you don't live near KC


KC police fire at backfiring van

Two Kansas City police officers who thought they were being shot at from inside a van returned fire Thursday night.



http://www.kansascity.com/2010/11/12...iring-van.html

Cajuncrawfishco

NOW thats some funny sh........really!

Was it a "van down by the river" ?

DS

hebdog7

Yeah it's pretty normal I think. My buddy has a '06 GTO with LTs, high flow cats, and Corsa Sports and his does it. Just installed a v.X SNL cam and it's way loud now, but he does it on purpose. I like it and think it's funny but to each it's own.