A8 Question for a Newbie
02-03-2018, 08:06 PM
#1
Burning Brakes
Thread Starter
A8 Question for a Newbie
My Corvette is a 2017 Z51 with the M7. Today, my father bought a 2017 Stingray, non-Z51 with the A8, NPP, and mag ride. It seems to work well, but it occasionally makes a really strange sound. It only seems to happen when the engine is at low RPMs (Between 1000 and 1500 RPM). It goes away if he steps on the gas. The sound is a really loud drone or reverberation. There is no vibration or warble sound and the car does not seem to behave abnormally when it does it. Does this sound familiar to any of you guys who have the A8 on your car? Is it normal? If not, is there anyone here who knows what causes it? Thanks for any information that you can give me.
02-03-2018, 09:06 PM
#2
Exhaust drone is very subjective, and what you describe (hard to just guess) sounds like it . Drone in our cars is a sympathetic vibration usually at the rpms you state .
Some people never notice it, some aren't bothered by it, and some can't stand even the least little bit of it.
If this is what he is experiencing, then he may want to keep the exhaust flaps closed all the time. I'm not sure what the procedure is on a '17, but it's in the OM.
Some people never notice it, some aren't bothered by it, and some can't stand even the least little bit of it.
If this is what he is experiencing, then he may want to keep the exhaust flaps closed all the time. I'm not sure what the procedure is on a '17, but it's in the OM.
Last edited by owc6; 02-03-2018 at 09:14 PM.
02-03-2018, 11:45 PM
#4
My Corvette is a 2017 Z51 with the M7. Today, my father bought a 2017 Stingray, non-Z51 with the A8, NPP, and mag ride. It seems to work well, but it occasionally makes a really strange sound. It only seems to happen when the engine is at low RPMs (Between 1000 and 1500 RPM). It goes away if he steps on the gas. The sound is a really loud drone or reverberation. There is no vibration or warble sound and the car does not seem to behave abnormally when it does it. Does this sound familiar to any of you guys who have the A8 on your car? Is it normal? If not, is there anyone here who knows what causes it? Thanks for any information that you can give me.
02-04-2018, 12:30 AM
#5
Le Mans Master
Member Since: Apr 2001
Location: Ex-SF Bay Area; now happily Denver area
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Have either the same thing or something very similar. With my M7. I call it groan noise. Had it to dealer a couple of times could not duplicate it. It has to be just at the right RPMs to gas pedal force . Might just be exhaust noise. But does not happen all the time.. Not really a bother unless it is really pronounced I guess. There are other posts on this.
02-04-2018, 01:27 AM
#7
02-04-2018, 08:58 AM
#8
Melting Slicks
My Corvette is a 2017 Z51 with the M7. Today, my father bought a 2017 Stingray, non-Z51 with the A8, NPP, and mag ride. It seems to work well, but it occasionally makes a really strange sound. It only seems to happen when the engine is at low RPMs (Between 1000 and 1500 RPM). It goes away if he steps on the gas. The sound is a really loud drone or reverberation. There is no vibration or warble sound and the car does not seem to behave abnormally when it does it. Does this sound familiar to any of you guys who have the A8 on your car? Is it normal? If not, is there anyone here who knows what causes it? Thanks for any information that you can give me.
02-04-2018, 10:23 AM
#9
Burning Brakes
Thread Starter
Thanks for the help, guys. Again, it's my dad's car, and he doesn't even seem to notice the drone. The car probably just needs a little break in. It was manufactured in 10/16, so with all that time sitting on the dealer's lot, I'm sure its going to take some time for everything to loosen up.
I'm convinced the sound has something to do with the AFM. It just doesn't make any sense otherwise. I'm going to try driving it in manual mode under the same conditions and see if the sound stops. If so, I might recommend a Range AFM disabler plug to eliminate the problem.
Again, if anyone else has any other ideas, let me know. Thanks for the help so far.
I'm convinced the sound has something to do with the AFM. It just doesn't make any sense otherwise. I'm going to try driving it in manual mode under the same conditions and see if the sound stops. If so, I might recommend a Range AFM disabler plug to eliminate the problem.
Again, if anyone else has any other ideas, let me know. Thanks for the help so far.
02-04-2018, 10:33 AM
#10
I would also bet on the AFM given the occurrence only under light load/low RPM conditions. In addition to NPP his car will have an additional set of valves in the exhaust that operate in V4 mode to improve the exhaust note so if the noise is during V4 operation but still unusual for that it could be an issue with one or both of those valves although typically they will set a DTC when they fail. My Z06 doesn't have these valves (and never goes into V4 mode anyway) and I think they may have been deleted from some of the other higher performance variants in later years because they are highly failure prone from heat developed on the track.
My Z06 developed a very odd noise when cold at about 600 miles and it was because the NH temp tag it wore home from the museum was vibrating at certain engine RPM with the NPP in track mode. Like many other Corvette sounds it was a little difficult to localize until I remote started it when cold and saw the tag doing its little happy dance.
My Z06 developed a very odd noise when cold at about 600 miles and it was because the NH temp tag it wore home from the museum was vibrating at certain engine RPM with the NPP in track mode. Like many other Corvette sounds it was a little difficult to localize until I remote started it when cold and saw the tag doing its little happy dance.