6 Speed Auto
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From: Fairfax VA
6 Speed Auto
I know this thread has been posted a couple hundred times on this forum, but with the new STS-V making its debut at Detroit with the 6L80 auto transmission, does anyone know if this will make its way into 2006 model year Vettes or will we have to wait longer? The STS-V will go on sale sometime in the fall as an 06 model, so Im hopeful we will see this transmission finally go into the C6. It is more than able to handle the hp/torque figures from the LS2. If anyone has any info on this I would greatly appreciate it.
-Chris
-Chris
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From: Greenville SC
go to gm hydramatic web site and read about x-15 transmission there is a graph showing the 0-60 times and fuel mileage with the 4-65 and the new trans and a statement about deproliferation of diff ratios
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From: Fairfax VA
Originally Posted by soonerou
go to gm hydramatic web site and read about x-15 transmission there is a graph showing the 0-60 times and fuel mileage with the 4-65 and the new trans and a statement about deproliferation of diff ratios
Racer
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From: Greenville SC
Burning Brakes
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From: meraux louisiana
great info. heres the chart
I found the hydramatic website. And was able to copy the chart. I am not sure exactly what it is explaining but i like the performance improvement of 4 to 7 %! And also fuel economy improvement of 1 to 4%. Seems like the future is bright. andy
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You have to be careful reading that chart. For a 3.15:1 rear axle, the chart shows the A6 gaining 2.6% economy, but *losing* 2% performance compared to the A4 used now. The A6 only looks good when you compare it to the A4 using the 2.73:1 rear axle. Then economy is nearly the same, but performance is up 5%. But note that's 5% over the A4 with the 2.73:1 ratio, and not over the A4 with the 3.15:1 ratio, which still wins for performance.
Burning Brakes
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From: meraux louisiana
6 speed automatic performance question
Wow. If the new transmission causes a loss of performance of 2 percent for a 2.6 percent economy gain I don't think it will help the sales of Corvettes with them.
The 2005 models with the four speed automatic will surely hold their value well! GM must know we don't buy Corvettes for economy. It already gets great mileage for it's power. Something doesn't make sense here.
I would think that a 6 speed automatic transmission would have to increase both economy and performance if it is to be desired.
Andy
The 2005 models with the four speed automatic will surely hold their value well! GM must know we don't buy Corvettes for economy. It already gets great mileage for it's power. Something doesn't make sense here.
I would think that a 6 speed automatic transmission would have to increase both economy and performance if it is to be desired.
Andy
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Originally Posted by 2000 green hornet
Wow. If the new transmission causes a loss of performance of 2 percent for a 2.6 percent economy gain I don't think it will help the sales of Corvettes with them.
The 2005 models with the four speed automatic will surely hold their value well! GM must know we don't buy Corvettes for economy. It already gets great mileage for it's power. Something doesn't make sense here.
I would think that a 6 speed automatic transmission would have to increase both economy and performance if it is to be desired.
Andy
The 2005 models with the four speed automatic will surely hold their value well! GM must know we don't buy Corvettes for economy. It already gets great mileage for it's power. Something doesn't make sense here.
I would think that a 6 speed automatic transmission would have to increase both economy and performance if it is to be desired.
Andy
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From: Fairfax VA
As always, thanks for the info guys. I have to say that a 6 speed is going to give a performance advantage to the car over the A4, regardless of the axle ratio. Look at todays Accords, they run 0-60 in 6.4 seconds with the V6 in part due to the engine, but also due to the fact that it has a 5 speed auto that keeps it within its powerband. Yes the LS2 has an amazing power curve, with more than adequate power at any rpm, yet it still makes more power in certain places than others. Having an 00 A4 coupe with the 2.73 rear, when you nail it going 30-40mph, there is often a slight hesitation as the revs build. Not that the car is lacking in power, but there is a half to full second delay as the car builds up revs. With the A6 it would allow the car more tightly spaced ratios over the A4, and thus better acceleration particuarlly for passing situations. I truly hope that it does make it into the 06 model year, which if it is the case I will hold off buying the C6 until the fall...
Burning Brakes
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From: meraux louisiana
2 Speed Powerglide Automatics in the beginning
Originally Posted by shopdog
A more complicated, heavier, and larger transmission, why would you expect it to be better? Perhaps it would be better if you wanted to get better gas mileage while towing a trailer with your Corvette. But with the broad torque curve of the LS2, there's really no reason for more than 4 speeds, and a well chosen rear axle ratio. Never was.
Maybe in the 00's we will see even more speeds. They do become more complicated and i guess heavier and larger, but I would hope they keep the Vette's powerfull engine ever more in the sweet spot of it's power curve as the car speed increases.
I would hope the engineers are seeing a way to give us a performance and economy increase at the same time. Any truck engineers working on a towing package for the Corvette should pack up and go try to tune those Cobras to their advertised horsepower. Ford needs you bad.
Those old two speed powerglides were not too much fun from a dead stop takeoff. Once you got to about 30 miles per hour though they really started to roll! 
Andy
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Originally Posted by Vette346
As always, thanks for the info guys. I have to say that a 6 speed is going to give a performance advantage to the car over the A4, regardless of the axle ratio. Look at todays Accords, they run 0-60 in 6.4 seconds with the V6 in part due to the engine, but also due to the fact that it has a 5 speed auto that keeps it within its powerband. Yes the LS2 has an amazing power curve, with more than adequate power at any rpm, yet it still makes more power in certain places than others. Having an 00 A4 coupe with the 2.73 rear, when you nail it going 30-40mph, there is often a slight hesitation as the revs build. Not that the car is lacking in power, but there is a half to full second delay as the car builds up revs. With the A6 it would allow the car more tightly spaced ratios over the A4, and thus better acceleration particuarlly for passing situations. I truly hope that it does make it into the 06 model year, which if it is the case I will hold off buying the C6 until the fall...
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Originally Posted by eugenee326
With the 6 spd auto I would imagine that the rear end ratio could be raised to increase performance substantially. Why wouldn't it be closer to the 6sp manual rear?
The way I read the specs for this thing, it looks like it belongs in a truck rather than a performance car. They've given it more low end grunt than the A4 (yet in the Corvette, you're already traction limited on the low end, so more grunt isn't wanted or needed), and the only way to get any top end is to use a really numerically low rear ratio.
It belongs in a truck, one that tows a trailer, because what's needed there is more low end, and high speed doesn't matter, so you can still use a stiff rear ratio. But for a relatively light car like the Corvette, it is all wrong.
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Originally Posted by 2000 green hornet
I go way back and remember the 50's Vettes with the two speed Powerglide automatics. Then I think in the 60's they starting offering three speed Turbo Hydramatics or something like that. Probably in the 80's maybe they came out with four speed automatics.
Maybe in the 00's we will see even more speeds. They do become more complicated and i guess heavier and larger, but I would hope they keep the Vette's powerfull engine ever more in the sweet spot of it's power curve as the car speed increases.
I would hope the engineers are seeing a way to give us a performance and economy increase at the same time. Any truck engineers working on a towing package for the Corvette should pack up and go try to tune those Cobras to their advertised horsepower. Ford needs you bad. Those old two speed powerglides were not too much fun from a dead stop takeoff. Once you got to about 30 miles per hour though they really started to roll! Andy
Those old two speed powerglides were not too much fun from a dead stop takeoff. Once you got to about 30 miles per hour though they really started to roll! Andy
I would say one thing about the old Powerglides, they turned out to be great transmissions for dragsters and circle track cars. They're very light, and can easily be made to be very strong.
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From: Fairfax VA
Originally Posted by shopdog
Because GM Powertrain didn't design the 6 speed to work that way. They chose to give it stiffer low gear ratios instead of giving it multiple overdrive gears (the MN6 has two overdrive gears). So a stiff rear would substantially limit top speed, and hurt MPG.
The way I read the specs for this thing, it looks like it belongs in a truck rather than a performance car. They've given it more low end grunt than the A4 (yet in the Corvette, you're already traction limited on the low end, so more grunt isn't wanted or needed), and the only way to get any top end is to use a really numerically low rear ratio.
It belongs in a truck, one that tows a trailer, because what's needed there is more low end, and high speed doesn't matter, so you can still use a stiff rear ratio. But for a relatively light car like the Corvette, it is all wrong.
The way I read the specs for this thing, it looks like it belongs in a truck rather than a performance car. They've given it more low end grunt than the A4 (yet in the Corvette, you're already traction limited on the low end, so more grunt isn't wanted or needed), and the only way to get any top end is to use a really numerically low rear ratio.
It belongs in a truck, one that tows a trailer, because what's needed there is more low end, and high speed doesn't matter, so you can still use a stiff rear ratio. But for a relatively light car like the Corvette, it is all wrong.
"...is coupled to a brand new six-speed automatic transmission, the GM 6L80. With a 6.00 ratio spread between first and sixth gears, this transmission should be able to fully exploit the blown engines broad torque curve while delivering decent fuel economy. The transmission also provides for manual gear selection as well as Cadillac's excellent Performance Algorithm Shifting, which makes the transmission feel at home on tracks and winding roads."
Racer
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From: Philadelphia PA
If the 6spd offers better performance with a 2.73 than a 4spd, it must have more aggressive ratios. So, I can't understand how a 6spd is slower than a 4spd with a 3.15 rear.... Even though it has to shift a couple more times the shifts should be faster with a smaller ratio spread.
I read that the transmission has an extra clutch to decouple from the torque converter. Allowing quicker and smoother downshifts... could it be decoupling from the torque converter under acceleration as well, then shifting, and re-engaging?
I read that the transmission has an extra clutch to decouple from the torque converter. Allowing quicker and smoother downshifts... could it be decoupling from the torque converter under acceleration as well, then shifting, and re-engaging?
Racer
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From: Horsin' Around in Norco California
Originally Posted by shopdog
You have to be careful reading that chart. For a 3.15:1 rear axle, the chart shows the A6 gaining 2.6% economy, but *losing* 2% performance compared to the A4 used now. The A6 only looks good when you compare it to the A4 using the 2.73:1 rear axle. Then economy is nearly the same, but performance is up 5%. But note that's 5% over the A4 with the 2.73:1 ratio, and not over the A4 with the 3.15:1 ratio, which still wins for performance.
Big deal . That means the A6 transmission will get 20.4 mpg instead of 20.0 with the A4 .