Tune issue on my A8?
 

Hi Gang,

I wanted to get everyones thoughts on something I have noticed via PDR video on my A8. It would seem that whenever my car is shifting from 4th gear to 5th gear, it loses rpm for a split second and then comes right back...not sure if this is a tune issue or not...you don't feel it in the car at all (IMO) but I have been seeing it in any video of my car shifting at 127/128 mph it would seem...from 4th to 5th gear. Here are two videos that show my possible issue. Around the 7-8 second mark in the video below...


And around the 7-8 second mark in this video as well...


Is this normal? Could it be the active handling kicking in? Anybody seen this?

I've seen that happen when I review my PDR vids. Take a look below (main straight away). I had the PDR in the wrong setting but you can see where the RPM dips a bit after the 4-5 shift. I don't feel a loss in acceleration so never cared.

i was going to refer to other people saying 4th to 5th gear in this car sucks ass, which is true.. but this issue is something else. the power you're losing is miniscule, but it's definitely noticeable... that's odd.

It sounds like the torque converter lockup clutch is slipping badly on the 4-5 shift, and a little bit on the 3-4 shift as well. (Or, it could be one of the other clutchpacks.)
Mine doesn't do that, but I've heard it on some dragstrip videos where a ZO6 had substantially more power than stock. Not sure if that meant the clutch was trashed, or if it just required more line pressure to handle the extra power.

If you have a warranty, show the video to the dealer service department and see what they say.

Lol, that's probably nothing more than the performance traction management controlling wheel spin and backing it off a tad. Mine does the same thing too and with all nannies turned off, it doesn't hook up completely till about 90-95 mph. So yeah, I can see PTM and TM kicking in at those lower speeds under full throttle. In your video, I didn't see any loss of acceleration, just a change in engine noise, that's all. Just my opinion here...good luck!

At 125 mph?

In Manual mode, paddle shifting from 4th to 5th at 6,500 RPM, shift is sharp and immediate (with the standard and unfortunate drop in acceleration from the gearing step). No 'pause' whatsoever in RPM as 5th is engaged. I'm skeptical about traction problems at 125 MPH on a dry road unless you have unusually high RWHP. Can't speak for Auto mode.

It's 100% normal factory behavior and it's just the converter locking up. In auto mode it usually starts to lock up around 128 mph just after the 4-5 shift and fully locks up over the course of about a half a second. How quickly it locks up depends on how much power you are making, etc.

can this be tuned out?

Yup, or at least mine does...