Bertrand

I'm wondering if this is normal, about once every 20 miles or so, if I go close to WOT in 2nd gear and back off the throttle significantly in 3rd, the car will make a POP noise through the exhaust. Only does it once and under these specific circumstances. Is this normal with the Z06? Should I be worried or get it checked out?

Car runs great otherwise and the occasional POP seems like it could be normal for such a performance car but I'm not sure. Thanks for your help!
:seeya

The DBK

Normal :yesnod: :cheers:

wsaracen

is that the same thing that happens when the race cars like the c5r have flames coming out of the exhaust when they let off the gas, on a much smaller scale i mean of course

ragvette

http://forums.corvetteforum.com/zerothread?id=316769

Normal, this may help.

LTC Z06

I LOVE the sound high compression engines make when you get off the throttle, my Harley does too :)

GRB

It's a no extra cost bonus!

Bertrand

Perfect! I think it sounds awsome as well because it reminds me of race cars when they lift throttle. I just wanted to make sure it was normal and nothing was wrong (silly me, didn't want to hurt the car...).

None of my straight 6s have ever done that even though the 2JZ-GE engine in the IS300s uses 10.5/1 compression ratio; but I'm sure Lexus just did something to prevent it because of the 'lux/performance' compromise of the car. Might also have to do with the overhead cam multivalve VS pushrod design, just guessing at this point.

It absolutely sounds vicious when it makes that noise! In a Darth Vader getting pissed kind of way. :reddevil :cool:

Thanks for the reassuring feedback! :cheers: :seeya

Corvette Junkie

I love that sound. :yesnod:

Bink

I love it!!! :cool: :cool: :cool: :cool: :cool: :cool: :cool: :cool: :cool: :cool: :cool: :cool: :cool: :cool: :cool: :cool: :cool: :cool:

Weasel

Yes, love love love :seeya

levettegrl

got the same POP last night!!! stock Z06

sodian

I hate that sound. I think it makes the car sound like crap, especially when it cold. :crazy:

TRZ06

It is very normal.

I just added a Corsa Pace exhaust system on my Z and now that popping sound is very pronounced. Some don't like it, however I love the sound, it adds to the idea of what the Z06 is about... a race car that is street legal.

Oh, and the occasional popping sound is not so occasional with the Corsa's on :yesnod:

QWK SLVR

Pretty cool, eh :cool:

I like it :cheers:

stingray454

It doesn't matter regarding multivalve OHC vs. pushrod design. The popping is caused by a) very little exhaust back pressure of a high performance exhaust system, b) excess unburnt fuel igniting in the hot exhaust manifold or the exhaust system, or a combination of both. In the case of the Z06, its a combination of the very high lift cam leaving a bit of unburnt fuel in the exhaust stream for a split second when you lift off the throttle, coupled with a very low restriction exhaust system with almost no back pressure.

Many turbocharged cars running high boost and rich fuel mixtures will also do this popping, sometimes with a loud bang and/or large flame out the tailpipe. I've seen and heard Supra Turbos and Audi S4s do it - its all normal, just unburnt fuel getting burned off. The same with the race cars such as the C5R.

Its funny though, when I first got my Z06 I posted a message/question almost exactly the same as yours! At first the popping made me nervous like there was something wrong. Now that I know what it is and that its normal, I like the popping sound! :cool:

Bertrand

Thanks for the great explanation stingray! Makes sense... I suspected that it was normal as well because I had heard it with some race cars but still wanted to make sure everything was cool. :yesnod: :yesnod:

Now that I know nothing is wrong, it definitely sounds cool in a "do YOU have 400+ horsepower under the hood with a titanium exhaust system?" kind of way. Gotta love it! Now if I could only get it to shoot four flames out the back on demand... :reddevil :reddevil :cool:


[Modified by Bertrand, 5:33 PM 6/17/2002]

Chuck Harmon

My L88 does the same thing, only more so, when I lift while in gear. Depends on the location and my mood at the time - sometimes I love it, other times I wish it could be more discreet. The Z does it in good measure, just enough to anounce you have something special without being obnoxious.

Chuck

Bill Curlee

Love the sound soooooooooo much that my wife intentionally makes it do it!!!!!

papavette

Is there an exhaust gate modification made for the Z06 to handle this?

bparker

Yep - mine does that - quite often really