Backfire
Melting Slicks
Joined: Jan 2017
Posts: 2,982
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From: Georgetown CA
2018 Corvette of Year Finalist
2017 C7 of Year Finalist
I can see someone thinking it is a backfire, or describing it as sounding akin to one, but it is not a backfire and is perfectly normal on hard acceleration and a quick 1-2 shift. Hope you didn't pay the dealer to check that out :-)
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Team Owner
Joined: Jul 2006
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From: Calgary, AB. There's a reason why white was the only color offered on every year Corvette. Proud Canadian German Jamaican!
St. Jude Donor '09, '12-'13-'14-'15-'16-'17
I always thought it happens on deceleration. 
Melting Slicks
Joined: Jan 2017
Posts: 2,982
Likes: 1,040
From: Georgetown CA
2018 Corvette of Year Finalist
2017 C7 of Year Finalist
That's a little different but similar, a little extra fuel firing off. If you're not getting it on acceleration on your 1-2 shift, you're not trying hard enough :-) And I think people have said it's more apparent with A8's, so if you have a M7 you may be missing out. I find that if you paddle shift it close to redline on the 1-2 shift it's nearly guaranteed...
Instructor
Joined: Dec 2006
Posts: 227
Likes: 119
From: Jasper Alabama
Willing to bet this is from the fuel cutoff between shifts. I believe I read on a post back in 14' that it happens within 100 milliseconds. Probably runs a little rich when the ecm fuels to avoid being too lean after the shift then it hits the heated exhaust and pops from ignition.
Team Owner
Joined: Apr 2005
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From: Northern NYs Adirondack Mountains,http://www.visitsacandaga.com.
From what I was told by a GM engineer it is a designed in feature that nano interrupts the power delivery .(I have a 15 auto) That results in a little torque burble that allows the trans to upshit faster. (FWIW it sounds dam good when it shifts)
I have had friends hear it and say something wrong with your car. WRONG its running fine!
For your youngsters on here back in the late 60s they were experimenting with switches to do this "break" They built crash box 4 spd manual trans that had every other tooth removed from the synchronizer <SPL> gears and to shift with foot on the floor you hit the button and put the trans into the next gear using no clutch resulting in a super fast shift
I have had friends hear it and say something wrong with your car. WRONG its running fine!For your youngsters on here back in the late 60s they were experimenting with switches to do this "break" They built crash box 4 spd manual trans that had every other tooth removed from the synchronizer <SPL> gears and to shift with foot on the floor you hit the button and put the trans into the next gear using no clutch resulting in a super fast shift
Last edited by 6spdC6; Jun 14, 2017 at 12:46 PM.
Safety Car
Joined: Aug 2012
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As noted by others with an automatic the pop/snap/crackle through the exhaust is normal with a WOT shift at redline power is cut very briefly (through severely retarding ignition timing I believe) which allows much faster shift completion. This power cut isn't done with manual transmission equipped C7s. You will hear a similar (but extended in length) sound when PTM is engaged in Track mode and power is being limited accelerating out of a corner.
