Eight-speed Automatic transmission
Thread Starter
Burning Brakes
Joined: Feb 2000
Posts: 1,195
Likes: 1
From: East Bay CA
Eight-speed Automatic transmission
In less than 30 months (9/2005-12/2007), three GM engineers authored at least 42 patents on eight-speed automatic transmissions. Go to Google Patent Search
https://www.google.com/?tbm=pts&hl=en
and enter this phrase
"general motors" (Usoro or Bucknor or Raghavan) "eight-forward" "seven torque-transmitting"
To my eyes, the most recent is 7303501. As I look over an enormous variety, I see ratio spreads of above 8 to 14. The 6L80E is near 6. When there are this many gears, the rear-end ratio becomes a non-issue.
The rub here is that the eight-speed automatic may not be ready in time for the 2014 C7.
http://www.autoguide.com/auto-news/2...ucts-late.html
https://www.google.com/?tbm=pts&hl=en
and enter this phrase
"general motors" (Usoro or Bucknor or Raghavan) "eight-forward" "seven torque-transmitting"
To my eyes, the most recent is 7303501. As I look over an enormous variety, I see ratio spreads of above 8 to 14. The 6L80E is near 6. When there are this many gears, the rear-end ratio becomes a non-issue.
The rub here is that the eight-speed automatic may not be ready in time for the 2014 C7.
http://www.autoguide.com/auto-news/2...ucts-late.html
Race Director
Joined: Feb 2012
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Team Owner
Joined: Sep 1999
Posts: 41,732
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From: Springfield MO
the A4 was carried over to the 2005 C6. The 2005 run was then extended several months because the A6 was not ready for prime time for the 2006's until around Sept/Oct instead of the normal June model year changeover.
Thread Starter
Burning Brakes
Joined: Feb 2000
Posts: 1,195
Likes: 1
From: East Bay CA
In less than 30 months (9/2005-12/2007), three GM engineers authored at least 42 patents on eight-speed automatic transmissions. Go to Google Patent Search
https://www.google.com/?tbm=pts&hl=en
and enter this phrase
"general motors" (Usoro or Bucknor or Raghavan) "eight-forward" "seven torque-transmitting"
To my eyes, the most recent is 7303501. As I look over an enormous variety, I see ratio spreads of above 8 to 14. The 6L80E is near 6. When there are this many gears, the rear-end ratio becomes a non-issue.
The rub here is that the eight-speed automatic may not be ready in time for the 2014 C7.
http://www.autoguide.com/auto-news/2...ucts-late.html
https://www.google.com/?tbm=pts&hl=en
and enter this phrase
"general motors" (Usoro or Bucknor or Raghavan) "eight-forward" "seven torque-transmitting"
To my eyes, the most recent is 7303501. As I look over an enormous variety, I see ratio spreads of above 8 to 14. The 6L80E is near 6. When there are this many gears, the rear-end ratio becomes a non-issue.
The rub here is that the eight-speed automatic may not be ready in time for the 2014 C7.
http://www.autoguide.com/auto-news/2...ucts-late.html
GM seems to have a new group of people furiously producing patents on automatic transmissions. Try entering this string into Google patents;
"general motors" transmission "nine-forward" (Phillips or Hart or Carey or Wittkopp)
In spite of the word "nine" in the search, many eight-speed patents show up. I suspect these are more representative of GM's new eight-speed AT family.
Interestingly, there are 24 patents on ten-speed automatics by these same guys.
https://www.google.com/search?num=10...1c.cYXwd3-5Efc
Last edited by Runge_Kutta; Oct 28, 2012 at 06:30 PM.
Racer
Joined: Jan 2012
Posts: 314
Likes: 64
I don't know why they would want an 8 speed, GM couldn't even program the 6 speed automatic so it was driveable.
They'll probably program it so it shifts into 8th gear at 15mph to save gas mileage, and then you'll have to push the pedal all the way to the floor to make it downshift, at which time it will do a 6 gear downshift and rip the rear end right out from under it, after a considerable delay imposed by the torque controls.
The actual transmission design will be a moot point, because they will slaughter it by the way they program it. It wouldn't matter if it was a 20 speed transmission, it still won't provide any torque or acceleration when it shifts into it's highest gear at under 20mph.
They'll probably program it so it shifts into 8th gear at 15mph to save gas mileage, and then you'll have to push the pedal all the way to the floor to make it downshift, at which time it will do a 6 gear downshift and rip the rear end right out from under it, after a considerable delay imposed by the torque controls.
The actual transmission design will be a moot point, because they will slaughter it by the way they program it. It wouldn't matter if it was a 20 speed transmission, it still won't provide any torque or acceleration when it shifts into it's highest gear at under 20mph.
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Race Director
Joined: Feb 2012
Posts: 10,776
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I tend to think of these 8-10 speed auto trannys like a number of electric/hybrid cars with single speed/CVT trannys. It may well feel like a continuously variable transmission with just a TON of torque that you never actively shift but that responds to your right foot.
Hence, the CHANGE!!
Hence, the CHANGE!!
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Team Owner
Joined: Feb 2001
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From: Short Hills, NJ
quite the 1/4 mile performer as well. 
Racer
Joined: Jan 2012
Posts: 314
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This very forum is filled with threads about the problems in the programing of the A6. Entire businesses have arisen just to reprogram this transmission.
Last edited by RainMan12; Oct 28, 2012 at 08:28 PM.
Race Director
Joined: Nov 2003
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From: Bergen county NJ
The GM automatic presently shifts from 1st to 2nd in 230 milliseconds and 2nd to 3 rd in 200 milliseconds. I drive manual transmission vetted and the programing impresses mec7 automatic will rock!
Team Owner
Joined: Feb 2001
Posts: 27,254
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From: Short Hills, NJ
Price/cost of ownership/ease of maintenance, fuel economy, styling (subjective), interior space/comfort, availability etc are all potential areas where the Corvette might actually have plenty of advantages over other sports/performance cars.
Racer
Joined: Jan 2012
Posts: 314
Likes: 64
Its not the time it takes to change gears that is the problem. It is the speeds and throttle angles at which it's programed to shift gears, as well as the torque control limits. If they don't address the programing downfalls, it will have the same crappy shift speeds programmed into it that the A6 does.
Burning Brakes
Joined: Mar 2010
Posts: 943
Likes: 159
From: Brighton Mi
You might want to ask yourself why so many A6 owners get their transmissions "tuned" so that the car will actually downshift when they step on the gas. Try doing some mild accelerations at 45mph next time you drive your car and see what happens. See how far you have to push on the gas pedal at 45mph before it downshifts, and then maybe you'll understand the problem, and if you push it far enough, you'll get to experience the infamous 4 gear downshift all the way to 2nd gear. If that isn't a driveability issue, I don't know what is.
This very forum is filled with threads about the problems in the programing of the A6. Entire businesses have arisen just to reprogram this transmission.
This very forum is filled with threads about the problems in the programing of the A6. Entire businesses have arisen just to reprogram this transmission.
Race Director
Joined: Dec 2011
Posts: 10,355
Likes: 12
You might want to ask yourself why so many A6 owners get their transmissions "tuned" so that the car will actually downshift when they step on the gas. Try doing some mild accelerations at 45mph next time you drive your car and see what happens. See how far you have to push on the gas pedal at 45mph before it downshifts, and then maybe you'll understand the problem, and if you push it far enough, you'll get to experience the infamous 4 gear downshift all the way to 2nd gear. If that isn't a driveability issue, I don't know what is.
This very forum is filled with threads about the problems in the programing of the A6. Entire businesses have arisen just to reprogram this transmission.
This very forum is filled with threads about the problems in the programing of the A6. Entire businesses have arisen just to reprogram this transmission.
Advanced
Joined: Feb 2012
Posts: 80
Likes: 18
From: New Hampshire
Faster than DCT Sequential atuomatoc or completley manual Shifting
A6 is now a Faster shifting transmission than DCT Transmission.
Sequential Manual Mode (user must downshift or start off in sixth gear or last gear used will not shift or downshift unless paddles ar used)
Automatic sport mode
(Fastest acceleration with .125 second shifts)(Faster than a DCT)
or user may select only manual Shifting
This is the current A6 in my 2012 GS .
A8 will without a doubt use the same spec's.
Note: A6 is Rated for 650 HP
A8 most likely will be rated for 750 HP.
Sequential Manual Mode (user must downshift or start off in sixth gear or last gear used will not shift or downshift unless paddles ar used)
Automatic sport mode
(Fastest acceleration with .125 second shifts)(Faster than a DCT)
or user may select only manual Shifting
This is the current A6 in my 2012 GS .
A8 will without a doubt use the same spec's.
Note: A6 is Rated for 650 HP
A8 most likely will be rated for 750 HP.
