Mine does it in sport/track mode under WOT shifts with my SP A8. I worked for an Indy team several years ago and their cars all had sequential shifters and when driver shifted he did not lift or use clutch (SWOL shift without lift).. The pop came when the computer instantaneously cut spark when shifter was moved resulting in a neat pop as they went through gears. Maybe it is similar with our A8s??
From what I've been reading elsewhere it's the a8 bouncing off the rev limiter. It doesn't occur while accelerating (rpm climbing), only during shifts. I probably haven't noticed it before because I wasn't really accelerating hard prior for the break in process.
Mine does something like that. I think it's the computer killing a cyl during hard shifts to prevent damage. I have no direct knowledge of our cars but I know other performance cars do it.
It has no effect on performance.
It's an automatic 8, I let the car shift itself while going WOT.
WOT should be fine after 500 miles, just no track until 1500 miles. Manual says WOT is fine in brief stints from 300 to 500 miles. Should be fair game after 500.
I'm not sure if you have done any mods or swapping out / deletions in your exhaust, but if so, the "burp" (if thats what your hearing) is very typical and can be loud, but its not a backfire. Its a flat spot of air/gas pulse in the exhaust pipe that occurs between shifts. This gas bubble if you will, is slower than the gases being pushed into the system after it, so it is compressed in the pipe, on release at the tail pipe, it will create a burp effect..more typical on some cars/engines than others, very common in tuners...Ive gotten it since the reso delete at WOT.
A true backfire (very loud abrupt pop) is indicative of unburned fuel (rich), firing off post combustion chamber and thats not normal nor good in anyway...
Hemi4us
^ Exactly this. Mine burps all the time between gears. Sound awesome. Never gotten a true backfire though. If you hear a pop that sounds like a gunshot, that's not normal. Unless you're in the "hood".