I wanted to share this and get some input. I have an '08 A6. It seems that I have a poor shift problem using the paddles shifters, but only in "S" when NOT in Competition mode, but not in "S" when I am in Competition mode. The problem is very specific to only this one mode and only when I use the paddle shifters.

Anyone else experience this?
Anyone have a clue as to what's happening?

A few words about the videos:

1 – These were taken with a Sony HandiCam
2 – They were “video captured” with a Pinnacle video conversion device
3 – “Shift Start” in the video is the “time stamp” of the video when the RPM pointer climbs through acceleration and then starts to fall (starting the shift)
4 – “Shift End” in the video is the “time stamp” of the video when the pointer starts to climb after the shift is complete
5 – There are 5 videos in total. They are respectively:
In “D” - shift time 0.70 seconds
In “S” and not using the paddles (not in COMP mode) - shift time 0.51 seconds
In “S” and using the paddles (not in COMP mode) - shift time 1.20 seconds!!!
In “S” and COMP mode and not using the paddles - shift time 0.44 seconds
In “S” and COMP mode and using the paddles - shift time 0.54 seconds
6 – The measured times here are very accurate (within 1 frame of video which is ~ 0.03 seconds).

Here are the videos...

 

The delay is very evident from the videos. It seems it's the transition of the shift, not the onset of the shift itself. Couple things:

1. Does it make these slow shifts only at WOT? What about 80% throttle?

2. I assume you have done this multiple times and there is no chance you are hitting the rev limiter on the nannies engaged paddle shifts?

3. I can almost guarantee that the computer nannies have something to do with this. I wonder if you are on the cusp of breaking traction and it is making the computer a little hesitant to shift because it's on the brink of engaging traction control. If I remember correctly the A6 WILL NOT shift while in paddle mode and traction control is engaged. I noticed traction control kicking in in the video and what may be happening is that the computer may not have time to reset before you command the 1-2 shift. I know that sounds ridiculous, but there is really no other explanation. If it was a mechanical problem it wouldn't matter what mode you were in, you would still have the "slipping" effect of the shift that you are getting. So it has to be a software computer issue.

4. Have you tried different street surfaces? Try it on another surface(which provides the best traction) and see if you still have the issue.


Edit: I'm gonna go try mine right now and see what happens.

Edit2: Nevermind, it's raining and the roads are all wet.

 

not sure what exact issue it is but on my 9 A6 if using paddles in S i think if i get the tires spinning and shift it doesnt and hits the rev limiter. This is normal from what some guys have said. I know this isnt the answer but if you get a good tuner they can fix issues like mine. Not sure if the dealer could fix your issue or not? I dont know if any of my post helps you?? If you PM me i can drive mine tomorrow and see if i can duplicate your issues, i dont use the paddles much. good luck, paul

 

Thanks for your thoughts!

A few things to add.
1 - I can repeat this issue at-will.
2 - It only happens in the one mode.
3 - I've experienced this issue on several different road surfaces.
4 - I have also experienced this when hitting the "+" button at a little lower RPM.

 

At a lower RPM but still at WOT? Try the same thing at 80-90% throttle and see if you have the same issue. Also, roll into the start and make sure you do not make traction control engage and see if it still does it.


If it doesn't do it then, try rolling into the start then applying 100% throttle (so traction control won't engage) and see if you have the same problem.

 

Yes, still at WOT.

I will try both the rolling start and 80-90% throttle tests tomorrow. Very good suggestions and I appreciate the input!

 

Bump

 

Xlnt post! Nicely done, very thorough.

I also notice the A6 shifts faster on its own compared to using the paddles.

But I am ashamed to say I have never used the paddles in COMP mode. Gotta give that a try... good enough reason to go for a drive today!

 

How'd the drive go?

 

Update...

Using SilverSpeed's input, I ran more tests today after it finished raining and the roads dried up (just detailed the Vette Saturday after my last tests).

Here's the dealio....

Same basic set of initial conditions. Did not pack the HandiCam this time as I know I can tell the difference between a 0.50 second shift and a 1.20 second shift.

Test 1 - Roll out from 0 MPH with a throttle setting of about 80% (enought to have an aggressive launch without squealing the tires and without the TC kicking in). Shift at about 6000RPM. Shift was absolutely clean and sharp.

Test 2 - Roll out and ease into the throttle (still quickly however as the car does like to accelerate ) and step into WOT so that I'm at WOT well before the shift and without squealing the tires and without TC kicking in). Shift at about 6000RPM. Shift was absolutely clean and sharp.

Test 3 - Perform test 2 but this time not shifting until 6500RPM. WHAM. ****-poor shift! The culprit is the rev limiter nanny! The nanny kicks in really quick but doesn't release for a while! The rev limiter is what is causing the long shift times!

So, my major concern is not valid. The real concern I have now is the delay between when you hit the "+" button and when the trans actually shifts! The delay absolutely sucks!!!

Mystery solved. Thanks for the input!!!

 

That's a pretty common issue. If you can hit the button at 6k and get a successful shift you are good, at least better/faster than most. Since the A6 came out we have been telling new owners here to initially start hitting the button at 5500 and work up as they get accustomed to the car. Few get past 5700-5800. You must have good reflexes and/or hand-eye coordination.

 

In the initial test in Comp Mode at what RPM were you hitting the paddles? Do you think you might have been hitting the paddles a little quicker in Comp Mode and not hitting the rev limiter?

Still not completely sure that traction control kicking in didn't have something to do with the slow shift in the initial test. In the second test you purposely avoided kicking it in so it's hard to tell if that had something to do with it or not.

Anyway, glad you figured out the mystery.

 

It is entirely possible that I was not hitting the button at exactly the same time. Even though I try, the RPM is accelerating very quickly at that part of the power band, especially in 1st. I can say confidently that I did not hit the button at exactly the same point every time. The peak RPMs during the shift did vary, and most assuredly it was due to when I hit the button.

TC could add another element to the equation I am sure. I just didn't test that as when I was out I thought to myself, "I wonder if I'm tagging the rev limiter?". When I did that test, bingo! The same crap shift time happened and the same "tranny slip" feeling occurred. But, it wasn't tranny slip, it was the rev limiter nanny. That's when I ended the test.

Hat's off to your suggestions. They pointed me in the right direction to be able to hit and control the problem. Controlling the problem is a majority of the battle. After you can control it, you get more confidfence you're on the right track.

Thanks Bro!

 

No problem man, glad you got it sorted out.

 

Just to confirm, next time I take her out I will test for teh TC portion. I will trip off the TC and shift at about 5800 to see if the TC causes poor shift times when I do not hit the rev limiter. I will post my results, probably in a few days. Stay tuned...

 

Weather turned threatening so I postponed my test.

 

Check out this new post of mine quantifying the delay between pressing the "+" button and the start of an actual shift sequence.

http://forums.corvetteforum.com/c6-c...post1570891086

 

Has anyone tested and quantified a Chuck Cow tune or Corvettes of Westchester tune for actual shift times (from Tach starting to drop to Tach starting to climb after the shift)?

 

The tach also seems to have significant lag. i.e., the actual rpm is higher than the indicated rpm during hard acceleration. That shouldn't effect shift lag times but the tach lag combined with shift lag sure makes it easy to get into the rev limiter.

 

you are absolutely right!

I just didn't want to quantify this aspect. Instead, I wanted to keep the test simple and do it in a way that others could test and try to reproduce things and maybe even compare data. Measuring time from pointer starting to drop to pointer starting to climb seemed a "good enough" measureable. Since there is filtering in the instrument cluster software which filters the movement of the TACH pointer, I figured that the filtering would have the same basic effect with the pointer moving in both directions (or close enough) so I eliminated this variable from the study for simplicity's sake and made the assumption that the TACH filtering was the same for both "pointer up" and "pointer down".