[lt4camaro]

Anyone having good luck manually shifting the A10 auto to get closer to a 6500 rpm shift at wot while running down the 1/4 mile track? (on a close to stock HP car) And I seem to be more comfortable nudging the shifter up rather than paddle shifting, speed of the shift should be the same ? yes / no

[arpad_m]

Hmm, doesn't it shift perfectly near redline in D when you're in performance shift mode? I'm not sure shifting at exactly 6500 rpm will give you the absolute highest power throughout each shift, by the way.

[2SS Capt]

Originally Posted by lt4camaro

Anyone having good luck manually shifting the A10 auto to get closer to a 6500 rpm shift at wot while running down the 1/4 mile track? (on a close to stock HP car) And I seem to be more comfortable nudging the shifter up rather than paddle shifting, speed of the shift should be the same ? yes / no

If you are trying to get the best times let the computers do the work in D... If you hit the rev limited in manual mode it will fall on it's face...

[lt4camaro]

Originally Posted by arpad_m

Hmm, doesn't it shift perfectly near redline in D when you're in performance shift mode? I'm not sure shifting at exactly 6500 rpm will give you the absolute highest power throughout each shift, by the way.

Normally wot shifts in drive are short, especially 1-2 and the 2-3 shift. Shifting as close as possible to red line and any gear for a 1/4 mile run should be beneficial. The hard core 1/4 mile guys that run the untuneable 10 speed auto trans hopefully have tried to manually shift closer to a higher rpm and can share the info if that it can be done or that the trans lets them do just that.

[lt4camaro]

Originally Posted by 2SS Capt

If you are trying to get the best times let the computers do the work in D... If you hit the rev limited in manual mode it will fall on it's face...

I agree and am well aware of hitting the rev limiter . But the A8 and the A10 both shift way short of redline in the 1-2 shift and the 2-3 shift at WOT. I have successfully made many passes down the 1/4 mile in manual trans corvettes and Camaros (C7 corvettes and 6 gen camaros) and making a shift close to redline and not hitting the rev limiter is a challenge. It has to be much easier with a auto trans. Its also been proven a good driver can get better ETs with out launch control. A highly sensitive driver can do better than the computer.

[arpad_m]

Originally Posted by lt4camaro

Normally wot shifts in drive are short, especially 1-2 and the 2-3 shift. Shifting as close as possible to red line and any gear for a 1/4 mile run should be beneficial. The hard core 1/4 mile guys that run the untuneable 10 speed auto trans hopefully have tried to manually shift closer to a higher rpm and can share the info if that it can be done or that the trans lets them do just that.

It certainly feels that way (maybe because of the awesome engine sound), but I don't think it is. Look at the torque/hp spec graph below, torque falls off on the LT1 drastically above 6000 rpm, and torque is what accelerates the car.

Taking the 1-2 shift as an example, a redline shift would be from 6500 rpm to ~4100 rpm, and if you compare the segment of the torque curve you traverse to, say, the one you'd see shifting at 5500 rpm to ~3500 rpm, the latter keeps you in a much stronger torque ("power") band for the final few seconds. Similar considerations apply to the 2-3 shift and even to higher gears, to a lessening extent.

The only time short shifting the A10 would hurt performance is if it caused an extra shift to occur during a given distance run, but I'm pretty sure this doesn't happen in a quarter mile. I'll be happy to be corrected in my amateur back of the envelope "analysis" if it isn't sound, though.

[lt4camaro]

Originally Posted by arpad_m

It certainly feels that way (maybe because of the awesome engine sound), but I don't think it is. Look at the torque/hp spec graph below, torque falls off on the LT1 drastically above 6000 rpm, and torque is what accelerates the car.

Taking the 1-2 shift as an example, a redline shift would be from 6500 rpm to ~4100 rpm, and if you compare the segment of the torque curve you traverse to, say, the one you'd see shifting at 5500 rpm to ~3500 rpm, the latter keeps you in a much stronger torque ("power") band for the final few seconds. Similar considerations apply to the 2-3 shift and even to higher gears, to a lessening extent.

The only time short shifting the A10 would hurt performance is if it caused an extra shift to occur during a given distance run, but I'm pretty sure this doesn't happen in a quarter mile. I'll be happy to be corrected in my amateur back of the envelope "analysis" if it isn't sound, though.

torque generates acceleration, horsepower generates MPH, WOT trans shifting is never based on torque curve. generally speaking WOT shifts are 400 to 500 rpm higher than horsepower peaks, if the LT1 in stock form has a 5900 horse peak, shifting at 6400 is beneficial. Watch the tach in a properly set up drag car and see each shift right at or very close to redline .

[vtirocz]

Originally Posted by lt4camaro

torque generates acceleration, horsepower generates MPH, WOT trans shifting is never based on torque curve. generally speaking WOT shifts are 400 to 500 rpm higher than horsepower peaks, if the LT1 in stock form has a 5900 horse peak, shifting at 6400 is beneficial. Watch the tach in a properly set up drag car and see each shift right at or very close to redline .

The power curve has everything to do with acceleration!! Regarding the OP’s question, I’d shift wherever it would result in max power under the curve for a given run. Last time I looked at the LT1 power curve and M6 gearing (for my car) shifting as close to redline as possible would result in max power under the curve. I assume this is the case for the auto gearing as well, but would need to run the #s to be sure.

[UnknownJinX]

For most NA engines, normally you want to shift as close to redline as possible. The idea is that you want to upshift at a point that would give you more wheel torque(what includes torque multiplication of the gears in transmissions) in the higher gear at the lower RPM you shift to than the RPM you are currently at in the lower gear, unless you hit redline first, which is often the case with an NA engine.

Engineering Explained has a good video on this topic:



With turbocharged engines, however, you can hurt acceleration by shifting at redline. This is because when the turbo starts to "choke" the engine at a higher RPM(especially if your turbo is small, or your factory tune is on the conservative side), your torque will drop off significantly and you are better off shifting earlier. There was an article that tested the 2.0T 1LE that observed exactly this. They actually achieved better 0-60 times by shifting at a lower RPM than running it all the way out to the redline.

I would think a supercharged engine would be more similar to an NA engine, not 100% sure, though.

[arpad_m]

Originally Posted by lt4camaro

torque generates acceleration, horsepower generates MPH, WOT trans shifting is never based on torque curve. generally speaking WOT shifts are 400 to 500 rpm higher than horsepower peaks, if the LT1 in stock form has a 5900 horse peak, shifting at 6400 is beneficial. Watch the tach in a properly set up drag car and see each shift right at or very close to redline .

..so my curiosity didn't leave me alone and I ran the numbers for my A8. Turns out you were right, 1-2 and 2-3 shifts are best done at redline, while subsequent ones need to be short for maximum power. I only calculated this up to the 1:1 gear, of course.

Thanks UnknownJinX for the video link, this one I haven't seen yet .

[lt4camaro]

Originally Posted by arpad_m

..so my curiosity didn't leave me alone and I ran the numbers for my A8. Turns out you were right, 1-2 and 2-3 shifts are best done at redline, while subsequent ones need to be short for maximum power. I only calculated this up to the 1:1 gear, of course.

Thanks UnknownJinX for the video link, this one I haven't seen yet .

There are a ton of Utube videos being recorded inside the car of many good 1/4 mile drivers. You can see the tach in many of them.

[KingLT1]

When my car was stock I ran my best times manually shifting only because I could rev out 1-2 and 2-3. Stock they are programmed to short shift in the event of wheel spin so it stays off the limiter. Once you are tuned letting the computer shift is faster because there is some shift torque recovery settings that can not be adjusted in manual mode that actually make the car a tad slower.

[lt4camaro]

Originally Posted by KingLT1

When my car was stock I ran my best times manually shifting only because I could rev out 1-2 and 2-3. Stock they are programmed to short shift in the event of wheel spin so it stays off the limiter. Once you are tuned letting the computer shift is faster because there is some shift torque recovery settings that can not be adjusted in manual mode that actually make the car a tad slower.

Thank you KingLT1, finally someone who has noticed WOT shifting patterns of the A8 and the A10 and was willing to share some fine details. Regarding the A10, what RPM were you actually pulling the paddles or nudging the shifter forward to make the shift ? 6000? how fast does the paddle or shifter actually shift the trans (delay) I am thinking maybe 5900 1-2 shift considering the speed of the rpm sweep I should be close and maybe 6000 the rest of the shifts during the 1/4 mile blast. MY dyno tuner typically raises the redline 200 RPM to keep guys like me from getting close to hitting the limiter.

[JSH]

I always drive mine in Manual mode using HUD. Like most other racers here, I can't do WOT in 1st or 2nd. So, to answer your question, I pull the paddle around 6200 and it shifts varying amounts of RPM thereafter depending on the shift - 2/3, 3/4, etc.

My main objection to going WOT in Sport/Auto is the inevitable downshift is impossible to predict and cope with. Even a 4/3 downshift at WOT spins the tires.

I'm a bit off topic here in that I have more hp and torque.

Originally Posted by lt4camaro

Thank you KingLT1, finally someone who has noticed WOT shifting patterns of the A8 and the A10 and was willing to share some fine details. Regarding the A10, what RPM were you actually pulling the paddles or nudging the shifter forward to make the shift ? 6000? how fast does the paddle or shifter actually shift the trans (delay) I am thinking maybe 5900 1-2 shift considering the speed of the rpm sweep I should be close and maybe 6000 the rest of the shifts during the 1/4 mile blast. MY dyno tuner typically raises the redline 200 RPM to keep guys like me from getting close to hitting the limiter.