6l80E 3-4 shift, Track only, can somebody at HPTuners take a look to see if there is

[bluegoat06]

Oh i'll insist , HPT support, can somebody check this abuse mode feature to see how can we disable it in the 6L80E trans.

Ill explain it again.

I was talking with a cadillac MASTER TECH. This is what he explained to me.

On the FRESH START... the computer has to see one.. just ONE 3-4 shift, before it will let you go WOT and shift it perfectly.

1-2, 2-3, and 4-5 are NOT AFFECTED under WOT.

see my prev thread

http://www.g8board.com/forums/showth...609&highlight=

ONLY the 3-4 is. Its a safety feature for abuse mode.


2 things you can do.

1 - Go in the burnout box.. quickly bump it to m4 while spinning the tires

2 - Drive in the staging lanes to 25mph in M, and bump it to 4th gear (track officials dont really like this)

AFAIK no one has found this issue in the Tune.

it sucks if you wanna 1/4 this car

[topher455]

Im right there with you guys. I have to hit the 3-4 in manual mode in the water box. Ive tried everything. Im beginning to wonder if the 3-4 clutch volume adapt is stored in volatile memory and resets on every key cycle.

[SK360]

Im right there with you guys. I have to hit the 3-4 in manual mode in the water box. Ive tried everything. Im beginning to wonder if the 3-4 clutch volume adapt is stored in volatile memory and resets on every key cycle.

Ugh glad I found this thread... Car was pissing me off at the track last night.

Trapped 119 both runs (Only got 2 due to rain) and both runs it hung 3-4 shift right before the traps. I think I had a 120-121 in it last night but the stupid 6L80 cock blocked me. Will know to try and get into 4th in the box next time.

08 Corvette A6 2.73's with Headers.

[68sstt]

Is this a g8 problem only? Does the corvette do this?
Has anyone found a solution to this yet?

[SK360]

Is this a g8 problem only? Does the corvette do this?
Has anyone found a solution to this yet?

Not G8 only as my Corvette does it. Very annoying.

[04blackgmc]

All the 6l80es do it. I fought the issue with mu G8 and my C6.

Just learned to either hit 4th in the burnout box or tune the car where i won't need 4th gear....

[Bluecat]

I keep reading about this on the forum, and still have never seen this happen. Kind of considered that it was circumstantial. Anytime on test drives 4th is always hit in my long drive way before getting on the highway. Thought maybe at the track all my guys just do zealous burnouts and end up in 4th without thinking about it, lol. So I started looking at logs from the track. Found logs from every car type (even G8's) that I can see I started the log before the car started moving, never shifted 4th before going down the track, and I can't find one that shows what you guys are talking about. G8's do have quirky things like delayed upshifting / hanging in gear for a while after WOT bursts and not locking the converter in manual mode. But I'm not sure what I'd be doing different from everyone else to keep this from happening.

[8850]

I keep reading about this on the forum, and still have never seen this happen. Kind of considered that it was circumstantial. Anytime on test drives 4th is always hit in my long drive way before getting on the highway. Thought maybe at the track all my guys just do zealous burnouts and end up in 4th without thinking about it, lol. So I started looking at logs from the track. Found logs from every car type (even G8's) that I can see I started the log before the car started moving, never shifted 4th before going down the track, and I can't find one that shows what you guys are talking about. G8's do have quirky things like delayed upshifting / hanging in gear for a while after WOT bursts and not locking the converter in manual mode. But I'm not sure what I'd be doing different from everyone else to keep this from happening.

Here's one with the 3-4 hanging up. But I solved my problem, I bought a 2012 Z06!

[DSteck]

I keep reading about this on the forum, and still have never seen this happen. Kind of considered that it was circumstantial. Anytime on test drives 4th is always hit in my long drive way before getting on the highway. Thought maybe at the track all my guys just do zealous burnouts and end up in 4th without thinking about it, lol. So I started looking at logs from the track. Found logs from every car type (even G8's) that I can see I started the log before the car started moving, never shifted 4th before going down the track, and I can't find one that shows what you guys are talking about. G8's do have quirky things like delayed upshifting / hanging in gear for a while after WOT bursts and not locking the converter in manual mode. But I'm not sure what I'd be doing different from everyone else to keep this from happening.

A bone stock car will do it. You might just have the Midas touch though.

[Bluecat]

Ok, now I'm really confused, lol. I thought the problem was until a 3-4 shift was done at part throttle, that it wouldn't do a 3-4 shift at WOT. That they just stay in 3rd and bang the limiter until you let up off the gas to make it shit. The log you posted looks like a normal clean 3-4 shift to me, didn't have to lift and shifted @ 6500 like all the other gears.

Congrats on the solution to your problem! Hard to beat a C6 as the solution to any problem.

[Bluecat]

Ok, I guess my problem after reading the complaints a little closer, was what I would call hanging in gear and what being called hanging in gear here are two different things. So you guys are just saying the 3-4 shift is lazier and takes longer for the first 3-4 shift? The log 8850 just put up dosen't look that bad to me. It starts at the appropriate time and the rpm pulls down at a rate as aggressive as any of the other wot shits in the log. I even went back to his first posted logs in the thread. Said the faster run was a hot lap and the slower was a restart. The shape of the engine rpm line depicting the shift looked lazier to me in the one he said was better. Help me out here guys... I'm afraid I'm going to look like an idiot for missing what ever you guys are talking about. Lol.

[8850]

Ok, now I'm really confused, lol. I thought the problem was until a 3-4 shift was done at part throttle, that it wouldn't do a 3-4 shift at WOT. That they just stay in 3rd and bang the limiter until you let up off the gas to make it shit. The log you posted looks like a normal clean 3-4 shift to me, didn't have to lift and shifted @ 6500 like all the other gears.

Congrats on the solution to your problem! Hard to beat a C6 as the solution to any problem.

Start with frame 4124 where commanded 3-4 shift occurs. Then scroll to frame 4207 where rpm is the lowest at shift. If you calculate the time you get 2.075 seconds. Then back up to frame 3957 where commanded 2-3 occurs. Again scroll down to frame 4004 at shift extension and calculate. This time for the 2-3 is only 1.170. And you can feel the lag at that 3-4 shift. And by the same method the 1-2 is 1.06 seconds. Slightly shorter than the 2-3 but comparable.

[04blackgmc]

The 3-4 will hang and take what seems 2 to 3 times longer than normal and also hit the limiter on occasions.

I tested it over and over. Turn the car off on the side of the highway and sit there, start it back up and do a wot blast and it will delay the 3-4 pretty bad. Do the same thing but hit the 3-4 shift part throttle then slow back down and do a 3-4 WOT blast.... No issues.

[realcanuk]

Have the same issue. When I look at logs the 3-4 shirt takes much longer than the other shifts to complete, even though the shift times are set the same.

[Bluecat]

I'm still not seeing it. I understand what your talking about. Obviously it exists, 04blackgmc stated that it will even cause it to hit the limiter sometimes. What you guys are describing I should be able to see in a log, I just haven't seen it yet, lol. First off, based off what 8850 said, your calculating your shift times completely wrong.

Let talk about how the 6L's shift in general. Being a clutch to clutch transmission, it does a pre-shift kind of prep. The hand off from one clutch to the next is a tricky process to implement smoothly without a bog or a flare. To ensure the max amount of consistency, it pre loads the oncoming clutch with a light amount of pressure to ensure its ready to strike and to make sure their is no air in the circuit. Under normal part throttle shifting it does this for a small amount of time (usually less than a second) and then kicks off the shift. The pre-shift prep is where our delay comes from in manual mode. It can't instantly shift when you slap a paddle because it wants to get everything ready first, which takes time.

In wot mode where the rpm qualifier is also used, it happens a little different. When the mph for the shift speed is met it goes ahead and changes to pre-shift mode. You will see the current gear change in the scanner, but that dosen't mean a whole lot. That doesn't mean its trying to shift, its just getting ready. Under normal circumstances the noid for each gear is basically solid on, and the line pressure noid is modulated to control the pressure to the clutch. When it goes into pre-shift mode they flop. The line pressure raises to the "shift pressure" and it starts modulating the noids for the on and off coming clutches. You will see it preload the oncoming gear just a little to get it primed. Then it waits... until the rpm qualifier is meet and actually kicks off the shift. So to say that the shift took "x" amount of time based off when "trans current gear" changes is incorrect. If there is a long amount of time between those events, all that means is that your wot shift speed is to low compared to what your have your wot shift rpm set to. It won't actually shift until both rpm and mph are met, but it starts getting ready as soon as mph is met (which is when you see "trans current gear" change)

From the 10.949 log above posted by 8850:

2-3 Shift starts at frame 3986 - 1:39.606s / Ends frame 4003 - 1:40.043s = 0.437s
3-4 Shift starts as frame 4186 - 1:44.614s / Ends frame 4199 - 1:44.941s = 0.327s

The 3-4 shift is a faster shift. Its even a better looking / cleaner shift by just looking at the rpm line compared to the 2-3. Which is what I look at when I look at a shift in a log. Both shifts kick off at about 6500, which I'll assume is what the wot shift rpm is set to in the tune. I seen no problems with the 3-4 shift in the mentioned log above.



But, that doesn't do anything for addressing the problem. Obviously there is something going on or there would not be so many of you reporting it. Now, the log above doesn't show it, but I did notice something in a few of the other logs I looked at in this thread. The incline of the mph line shows the acceleration of the vehicle. I noticed in at least one log that the car was flat at the top of 3rd and not doing a whole lot. At first I assumed it was just someone shifting a car at 6500 that needed to be shifted earlier, lol. But then I though maybe it was pre-shift mode dragging the car down. The down side of setting the shift speed to early is that it does stay in pre shift mode a long time. And if the pressure used to prime the oncoming clutch is to high, your actually dragging the car down and burning up your clutches while you waist HP. The tcm is always learning and adapting. It may be that what is happening is to heavy and long off a pre shift prime pressure that is getting corrected for in subsequent shifts and is getting lost on a key cycle. On the first shift where you are seeing the problem, does it feel like the brakes are dragging and the car is smothered at the top of 3rd?

[8850]

I'm still not seeing it. I understand what your talking about. Obviously it exists, 04blackgmc stated that it will even cause it to hit the limiter sometimes. What you guys are describing I should be able to see in a log, I just haven't seen it yet, lol. First off, based off what 8850 said, your calculating your shift times completely wrong.

From the 10.949 log above posted by 8850:

2-3 Shift starts at frame 3986 - 1:39.606s / Ends frame 4003 - 1:40.043s = 0.437s
3-4 Shift starts as frame 4186 - 1:44.614s / Ends frame 4199 - 1:44.941s = 0.327s

Wrong perhaps, but I'm only making a comparison between the time shifts are commanded to shift extension, or how far the rpm falls until rpm and speed begins to increase. The 1-2 and 2-3 have shorter spans than the 3-4.

[Bluecat]

I wasn't trying to be negative or poke at any body. I was just trying to explain whats and the whys on the trans current gear pid changing so far before the actual shift. Like in the above log it changes from 3 to 4 at 104mph, but dosent actually reach 6500rpm and start the shift until 113mph. If you have the wot shift speed for the 3>4 set to 104mph and the 3>4 rpm set to 6500rpm, thats exactly what its supposed to do. Setting the mph to 108 would make that time your seeing shorter, 100mph would make it longer. And of course change how long it spends in the pre shit mode. But neither have anything to do with the actual shit that happens at 6500. If your on the same tune and the only diffference is first wot 3>4 shift vs subsequent 3>4 shifts and your seeing shorter times, then the car is taking less time to get from 104 to 113 on the second pass and the car is flat out accelerating faster. Which brings me back to the pre apply pressure on the 4th gear clutchs may be binding up and slowing the car down.

[realcanuk]

I'm still not seeing it. I understand what your talking about. Obviously it exists, 04blackgmc stated that it will even cause it to hit the limiter sometimes. What you guys are describing I should be able to see in a log, I just haven't seen it yet, lol. First off, based off what 8850 said, your calculating your shift times completely wrong.

Let talk about how the 6L's shift in general. Being a clutch to clutch transmission, it does a pre-shift kind of prep. The hand off from one clutch to the next is a tricky process to implement smoothly without a bog or a flare. To ensure the max amount of consistency, it pre loads the oncoming clutch with a light amount of pressure to ensure its ready to strike and to make sure their is no air in the circuit. Under normal part throttle shifting it does this for a small amount of time (usually less than a second) and then kicks off the shift. The pre-shift prep is where our delay comes from in manual mode. It can't instantly shift when you slap a paddle because it wants to get everything ready first, which takes time.

In wot mode where the rpm qualifier is also used, it happens a little different. When the mph for the shift speed is met it goes ahead and changes to pre-shift mode. You will see the current gear change in the scanner, but that dosen't mean a whole lot. That doesn't mean its trying to shift, its just getting ready. Under normal circumstances the noid for each gear is basically solid on, and the line pressure noid is modulated to control the pressure to the clutch. When it goes into pre-shift mode they flop. The line pressure raises to the "shift pressure" and it starts modulating the noids for the on and off coming clutches. You will see it preload the oncoming gear just a little to get it primed. Then it waits... until the rpm qualifier is meet and actually kicks off the shift. So to say that the shift took "x" amount of time based off when "trans current gear" changes is incorrect. If there is a long amount of time between those events, all that means is that your wot shift speed is to low compared to what your have your wot shift rpm set to. It won't actually shift until both rpm and mph are met, but it starts getting ready as soon as mph is met (which is when you see "trans current gear" change)

From the 10.949 log above posted by 8850:

2-3 Shift starts at frame 3986 - 1:39.606s / Ends frame 4003 - 1:40.043s = 0.437s
3-4 Shift starts as frame 4186 - 1:44.614s / Ends frame 4199 - 1:44.941s = 0.327s

The 3-4 shift is a faster shift. Its even a better looking / cleaner shift by just looking at the rpm line compared to the 2-3. Which is what I look at when I look at a shift in a log. Both shifts kick off at about 6500, which I'll assume is what the wot shift rpm is set to in the tune. I seen no problems with the 3-4 shift in the mentioned log above.



But, that doesn't do anything for addressing the problem. Obviously there is something going on or there would not be so many of you reporting it. Now, the log above doesn't show it, but I did notice something in a few of the other logs I looked at in this thread. The incline of the mph line shows the acceleration of the vehicle. I noticed in at least one log that the car was flat at the top of 3rd and not doing a whole lot. At first I assumed it was just someone shifting a car at 6500 that needed to be shifted earlier, lol. But then I though maybe it was pre-shift mode dragging the car down. The down side of setting the shift speed to early is that it does stay in pre shift mode a long time. And if the pressure used to prime the oncoming clutch is to high, your actually dragging the car down and burning up your clutches while you waist HP. The tcm is always learning and adapting. It may be that what is happening is to heavy and long off a pre shift prime pressure that is getting corrected for in subsequent shifts and is getting lost on a key cycle. On the first shift where you are seeing the problem, does it feel like the brakes are dragging and the car is smothered at the top of 3rd?

Thank you for this very good explanation of how the shifts work. I never really got the whole picture straight in my mind before. I always got the most results by changing mph, more than rpm. I am going to look at a bunch of logs and check that your explanation makes sense on my car. If it is working as you say, it might really help to get things more consistent.
I will update with findings when I can.

Thanks again for the input.

[SK360]

Blue,

Don't exactly remember the feeling since I have been doing all I can to avoid that shift at the track since.

But I can tell you that even driving it around at 10% throttle, letting it complete a 3-4 shift at 20 or whatever mph then going WOT, there are no issues with the shift. Same with getting it into 4th in the waterbox.

It happens on bone stock cars on stock tune as well.

I can do more logging once winter ends.

[Bluecat]

What you guys log would make a big difference on what I can see. The data rate is so fast on the new stuff there is no reason to not have your pid table full. Doing trans tuning I "need" to see Trans current gear, Delivered engine torque, PCS Pressure 1 - 5, TCC Line pressure, and tcc slip rpm. Would "like" to see if you have room, trans temp, Time of last shift, Trans calculated gear ratio. On the gear ratio part, that pid maxes out at 4.0. That is actually less that what first gear is. I chased my tail for years on cars that had 1>2 trouble because of this. The tranny can be slipping in 1st, but youll never know it because the pid it truncated. If you log trans input and output, and make a custom pid for trans gear ratio, you can really tell more about whats going on in 1st gear.

Get me a log with all that data, one that shows a bad 1st 3>4 wot shift and then a subsequent good 3>4 wot shift and maybe we can get to the bottom of this. Plus a copy of the tune that was used to make the log.