backfire
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6th Gear
Joined: Aug 2008
Posts: 6
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From: Pawhuska OK
backfire
Test drove C7 Grand Sport 2019 yesterday that backfired thru when I heavy accelerated from a stop.
Is this normal ?? Car only had 6,200 miles on it. Thinking of upgrading from our C6.
Is this normal ?? Car only had 6,200 miles on it. Thinking of upgrading from our C6.
Le Mans Master
Joined: Mar 2010
Posts: 7,052
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From: DFW TX
Backfired or just starting popping when you were on it hard and then let off the gas? The exhaust popping on decel is very normal. If the car truly backfired that is not, however I think you're just hearing the exhaust screaming 
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OP;
If it is for sure "back-firing" under load, then there is an issue with the tuning of the engine.
Normally, it is unburnt fuel hitting the exhaust and igniting usually exaggerated by lean conditions due to the higher exhaust temps. If you have the NPP (GS models do) exhaust in quiet mode you will rarely hear it, but it's quite pronounced with the NPP exhaust in the open position.
I would strongly suggest up-dating and up-grading to the newest possible C7 Corvette, you and your family can afford.
"You will not be disappointed".
Many thanks,
Ray
If it is for sure "back-firing" under load, then there is an issue with the tuning of the engine.
Normally, it is unburnt fuel hitting the exhaust and igniting usually exaggerated by lean conditions due to the higher exhaust temps. If you have the NPP (GS models do) exhaust in quiet mode you will rarely hear it, but it's quite pronounced with the NPP exhaust in the open position.
I would strongly suggest up-dating and up-grading to the newest possible C7 Corvette, you and your family can afford.
"You will not be disappointed".
Many thanks,
Ray
Le Mans Master
Joined: Oct 2014
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From: Atlanta GA
Are u talking about the POP on the shift , that s normal as the ECM cuts the ignition for a mili second on the shift which results in the POP you heard
I did the same thing on my test drive , scared the hell out of me as I thought something broke lol
Dave
I did the same thing on my test drive , scared the hell out of me as I thought something broke lol
Dave
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Ask the dealer to check the car over due to your concern. If not from a Chevy dealer, ask if they will take it to a local Chevy dealer for evaluation.
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I would test drive the car again, under hard acceleration. First in sport mode, then in touring mode, then in eco mode.
[I welcome a correction here] If you hear the same loud noise (that you thought was a backfire) then there is a problem, otherwise not.
[I welcome a correction here] If you hear the same loud noise (that you thought was a backfire) then there is a problem, otherwise not.
Le Mans Master
Joined: Oct 2014
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From: Atlanta GA
The OP needs to define when this noise happens and how often ... as there is not enough info here
If uts a pop during hard acceleration right at the shift from 1st to 2nd and if going fast enough 2nd into 3rd ... then it's normal
If uts a pop during hard acceleration right at the shift from 1st to 2nd and if going fast enough 2nd into 3rd ... then it's normal
Melting Slicks
Joined: Aug 2014
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100 % Agree! Spot on normal for the A8 with NPP (I can't speak for the manual or A6 cars with NPP)...those that say this is not normal (with A8/NPP) must have never really pushed hard on the throttle - LOL
Last edited by lakemg; Jan 22, 2021 at 02:49 PM.
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Tire noise depends a lot on what kind of pavement you're driving on, and of course on speed.
Newer tires are quieter than older used tires of the same model, so comparisons are difficult.
Most people here say the AS3+ ZP are quieter than the PSS ZP that come on the car, and a bit smoother.
We bought AS3+ ZP and a second set of wheels just after buying the car itself, swap out every Spring & Fall, so I have done back to back comparisons when each set of tires was almost new, and at about 10k/20k/30k miles. Most of the time, I can't tell any difference between them in ride or noise. Except that the AS3+ don't throw small stones at the bottom of the car like the PSS do.
Newer tires are quieter than older used tires of the same model, so comparisons are difficult.
Most people here say the AS3+ ZP are quieter than the PSS ZP that come on the car, and a bit smoother.
We bought AS3+ ZP and a second set of wheels just after buying the car itself, swap out every Spring & Fall, so I have done back to back comparisons when each set of tires was almost new, and at about 10k/20k/30k miles. Most of the time, I can't tell any difference between them in ride or noise. Except that the AS3+ don't throw small stones at the bottom of the car like the PSS do.
Last edited by Gearhead Jim; Jan 24, 2021 at 01:55 PM.
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Different brands/models have different noise characteristics. Toyo R888 Proxes are wonderfully sticky and provide all the traction your GS will need, but are quite loud in comparison to other patterns. My Notto NT05s were decent for noise and great tractions. Currently have Michelin PSSs that are OK for both and had Eagle F1 G2 that were decent for noise but traction was wanting.
