Question about manually shifting an auto

[SlingShot]

Originally Posted by mikeinmobile

Mine def does the funky 1st to 2nd manual shift, I don't like it. Biggest prob w/leaving it in drive is the 2nd gear start off the line. Does comp mode start in 1st or do you still have to manual shift to be in 1st. I bought her new so she hasn't been tuned.

There have been several write up's about the SS and 1st gear. If memory is working properly it's been proven the SS starts in 1st gear in both Drive and Sport. I know for a fact the ZL1 starts in 2nd while in Drive, and 1st while in Sport. Also with my Sedan SS with 6l80, it starts in 1st in both Drive and Sport, and doesn't auto shift while in manual mode.

[brick59]

Originally Posted by 1JEWLDSSRS

Yep, no way to disable it, or make the shifts any quicker, according to my tuner. That's why when you want to race the car, leave it in sport mode so the computer can "do it's thing" as tuned. Reason being is that the computer is set to tell the trans and get it primed to shift and what line pressure and all that jazz BEFORE it actually dos the shift. What I have noticed in mine is that there is about a 1 second and about 200rpm's before the "manual" shift you do actually happens, so yea it is useless...Unless you like using it just driving around town so you can pick a gear to drive in.. Just my experiences over the many years of owning my Camaro and using the tapshift..

Yep.

Tap shift is not adaptive and that is why it is slower. When a 6l80/6l90 is in normal or sports mode the computer anticipates the oncoming shift and it prefills the clutch packs, when it’s in tap shift it has no way to know when the command to shift is coming so it can’t prepare for the shift. These transmissions are complicated on how they hand off from gear to gear.
If you're drag racing have your tuner set it up for sport mode to shift when you want it to, and let the computer do the work, the car will be faster and more consistent.

[1JEWLDSSRS]

Originally Posted by brick59

Yep.

Tap shift is not adaptive and that is why it is slower. When a 6l80/6l90 is in normal or sports mode the computer anticipates the oncoming shift and it prefills the clutch packs, when it’s in tap shift it has no way to know when the command to shift is coming so it can’t prepare for the shift. These transmissions are complicated on how they hand off from gear to gear.
If you're drag racing have your tuner set it up for sport mode to shift when you want it to, and let the computer do the work, the car will be faster and more consistent.

This exactly, thanks. I did some runs at the strip back when I only had the basic mods and the difference in trying to shift in manual and sport was totally night and day, in sport the car was about 1.5-2 secs quicker than in manual, so tapshift is junk at the track. Plus I read on here somewhere that when running in manual mode the ECM will pull timing and adjust the AFR so as to not hurt the engine while YOU are telling it when to shift and such.

[1JEWLDSSRS]

Originally Posted by gunchamp

Running in manual (m) on the shifter and it most certainly will not hold a gear. If i punch it, it up shifts on its own and does this weird shit like pretty much bailing on 2nd and limping into 3rd. Would be awful in a race

Oh wow, mine doesn't do that at all!! Only if I bounce it off the limiter will it autoshift up. In first it will hold first, if I do a launch in 2nd, it will hold 2nd until I shift it. I can run it all the way to pre-redline and shift in either 1st or 2nd..

[102SS]

Mine will only upshift on its own when its in sport mode and I don't hit the paddles.

Once I play with the paddles it only down shifts on its own.

I accidently hit the paddles once going around the water box at the dragstrip and I hit the rev limiter just before the 1/8th mile and she threw out the boat anchor costing me an stock 12.9X pass.

Had to settle on the 13.08 as she just didn't want to run that quick again

[1JEWLDSSRS]

Yes, it is designed to downshift on its own, but the upshift HAS to be done by you, or that will happen, also when they downshift, it is set to only go down to 2nd, if you want 1st in manual mode, you have to select it, been that way since stock, and now tuned, but don't forget to upshift as 1st runs out real quick. lol.

[Moto-Mojo]

It seems there are two distinct thoughts here. Some say it definitely up shifts in manual mode and others say it never does. Not sure if it’s the tuned cars that act differently. When mine was stock, it just hit the limiter and fell off, big time, no up shift. Now that I’m tuned, not sure what it would do.

[gunchamp]

Originally Posted by 1JEWLDSSRS

Oh wow, mine doesn't do that at all!! Only if I bounce it off the limiter will it autoshift up. In first it will hold first, if I do a launch in 2nd, it will hold 2nd until I shift it. I can run it all the way to pre-redline and shift in either 1st or 2nd..

I may not be explaining it correctly, but I think yours does the same. If I approach the rev limiter using the paddles in 1st, it will automatically shift to 2nd, but only stays in 2nd for a short time and it zaps my power. It feels like a built in nanny to me. Not an issue

[gunchamp]

Originally Posted by Moto-Mojo

It seems there are two distinct thoughts here. Some say it definitely up shifts in manual mode and others say it never does. Not sure if it’s the tuned cars that act differently. When mine was stock, it just hit the limiter and fell off, big time, no up shift. Now that I’m tuned, not sure what it would do.

Yeah I'm a little confused as the are 2 different sides reporting here. I'll have to hit
Ryan up at GPI and explain to him whats going on. Maybe he can clear things up for us. Thanks guys for all the input and help so far!!

[SlingShot]

Originally Posted by brick59

Yep.

Tap shift is not adaptive and that is why it is slower. When a 6l80/6l90 is in normal or sports mode the computer anticipates the oncoming shift and it prefills the clutch packs, when it’s in tap shift it has no way to know when the command to shift is coming so it can’t prepare for the shift. These transmissions are complicated on how they hand off from gear to gear.
If you're drag racing have your tuner set it up for sport mode to shift when you want it to, and let the computer do the work, the car will be faster and more consistent.

Exactly, that's the thing I love about these trans. In my Sedan when in Sport mode, and you floor it coming out of a turn the DIC flashes Performance Shifting Enabled. Once it does that, the TCM just takes over and learns your driving style. Now when it shifts it hits hard, and even harder after getting it tuned.

My ZL1 learns and is very badazz when it shifts up and down. It does all that rev matching even when shifting itself. I love Chevy for programing these things to run the way they do.

[gunchamp]

Ok, so I'm going to do some data logging when I can actually drive for an extended period. Insurance goes back on in the next couple weeks, so I can actually take it further than just around my home. I spoke with James @ GPI and he said that they tune the trans to be ran in "D" as the best option for say, drag racing and general driving. The manual thing will happen as I described and can not be disabled from what they said. The computer takes over in manual mode using the paddles if you dont shift before the rev limiter hits. Sucks but is what it is.

[SSEssence]

For drag launches, Sport mode in auto will always be faster than the laggy paddles. I had my tuner set my trans tune so in Sport on a roll, I can set the start gear with the paddle and auto shift at redline, much better than stock.

[1JEWLDSSRS]

Originally Posted by gunchamp

I may not be explaining it correctly, but I think yours does the same. If I approach the rev limiter using the paddles in 1st, it will automatically shift to 2nd, but only stays in 2nd for a short time and it zaps my power. It feels like a built in nanny to me. Not an issue

Yep, this is it..But mine will only shift if I hit the limiter, if I stay below 7400, it will not shift until I do it..But the rest you describe is mine too..

edit; fixed the redline number from 7200 to 7400, my auto shift is 7200, redline is 7400.

[1JEWLDSSRS]

Originally Posted by gunchamp

Yeah I'm a little confused as the are 2 different sides reporting here. I'll have to hit
Ryan up at GPI and explain to him whats going on. Maybe he can clear things up for us. Thanks guys for all the input and help so far!!

Yes sir!!