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Tune issue on my A8?

 
Old 10-22-2018, 09:05 AM
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Chi-Town ZR1
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Default 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?

Last edited by Chi-Town ZR1; 10-22-2018 at 09:13 AM.
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Old 10-22-2018, 03:38 PM
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Bump...anybody have any thought?
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Old 10-22-2018, 04:07 PM
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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.

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Old 10-22-2018, 04:57 PM
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Originally Posted by blackbirdws6 View Post
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.

https://www.youtube.com/watch?v=FMSqkQQFGIk&t=153s

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Old 10-22-2018, 08:01 PM
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i was going to refer to other people saying 4th to 5th gear in this car sucks ***, which is true.. but this issue is something else. the power you're losing is miniscule, but it's definitely noticeable... that's odd.
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Old 10-22-2018, 11:23 PM
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Virtually all manufacturers employ torque management to help preserve the transmission. So the power is pulled back for a split second during shifts, so I’m willing to bet that’s the case here.
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Old 10-23-2018, 06:24 AM
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Warp Factor
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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.
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Old 10-23-2018, 09:17 AM
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Originally Posted by Warp Factor View Post
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.
hmmm. I donít feel it at all, just noticed it in my pdr. Now you got me wondering. Lol.
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Old 10-23-2018, 10:43 PM
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Warp Factor
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If you have a warranty, show the video to the dealer service department and see what they say.
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Old 10-23-2018, 11:38 PM
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Originally Posted by Warp Factor View Post
If you have a warranty, show the video to the dealer service department and see what they say.
could this be a triple flush needed issue??

https://www.corvetteforum.com/forums...ot-wait-2.html
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Old 10-24-2018, 01:22 AM
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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!

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Old 10-24-2018, 05:56 AM
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Originally Posted by GeorgeR_Zed06 View Post
Lol, that's probably nothing more than the performance traction management controlling wheel spin and backing it off a tad.
At 125 mph?

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Old 10-24-2018, 09:34 AM
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It happens to mine as well. Iíve worried about it at first but was told itís a lockup of some sorts and not to worry about it so I stopped asking questions. Hereís my proof it happens.
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Old 10-24-2018, 09:48 AM
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Originally Posted by LuckyC7Z06 View Post
It happens to mine as well. Iíve worried about it at first but was told itís a lockup of some sorts and not to worry about it so I stopped asking questions. Hereís my proof it happens.
https://youtu.be/3ttDT5HUkMc
dam! Great video!!! What are your mods? What were you racing?
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Old 10-24-2018, 12:13 PM
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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.

Last edited by mikegaan; 10-24-2018 at 12:23 PM.
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Old 10-24-2018, 02:37 PM
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Originally Posted by Chi-Town ZR1 View Post


dam! Great video!!! What are your mods? What were you racing?
At that time 15% pulley,cam and NX spray bars. That car is a Vengeance Racing Lambo he was running 190-195mph.
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Old 10-24-2018, 03:34 PM
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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.

Last edited by NicD; 10-24-2018 at 03:34 PM.
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Old 10-24-2018, 03:59 PM
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Originally Posted by NicD View Post
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.
why does it do that? Does it effect acceleration or performance? Can it be tuned out?
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Old 10-28-2018, 10:51 PM
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can this be tuned out?
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Old 10-29-2018, 01:42 AM
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Originally Posted by Warp Factor View Post
At 125 mph?
Yup, or at least mine does...
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