2015 A8, is EIGHT enough
Team Owner
Joined: Apr 2001
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From: S.W. Ohio. . . . . . NRA Life Member
sure; the old tranny shifted in 300ms. The new tranny shaves 50ms off each shift ... but adds an additional shift or two in the 1/4 mile.
Somehow, this makes it faster...
Somehow, this makes it faster...
Thread Starter
Team Owner
Joined: Sep 1999
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From: Swansea IL
Advanced
Joined: Aug 2013
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From: Alexandria Minnesota
You guys realize that the 2014 Cadillac CTS V Sport with a 8- speed Auto that is available Now, has skip shift because all the gears are not necessarily needed all the time, it also has a 420 hp twin turbo V-6
Melting Slicks
Joined: Jun 2004
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From: Granbury, Pecan Plantation TX
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From: Calgary, AB. There's a reason why white was the only color offered on every year Corvette. Proud Canadian German Jamaican!
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Team Owner
Joined: Apr 2001
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From: S.W. Ohio. . . . . . NRA Life Member
RIF; the one the OP mentioned, the Chrysler tranny.
But, I know you got the point of it anyways ...
But, I know you got the point of it anyways ...
the question is, is the extra shift in the quarter with the A8 going to nullify the difference in transmissions
Pro
Joined: Jul 2014
Posts: 602
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From: Southern Ontario
As with the ability to go to 4 cylinders. It's all about fuel mileage but they will continue to market the performance aspect and why wouldn't you. To the average Joe it probably means little to have an A6 or A8 other than bragging rights, my tranny has more gears than your tranny.
Team Owner
Joined: Apr 2001
Posts: 54,204
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From: S.W. Ohio. . . . . . NRA Life Member
the A4 in the C5 (and 2005 C6)... had one overdrive gear; 4th.
The C6 A6; 5th and 6th (the last two) were overdrives.
in the A8, same... the last two (7th and 8th) are the only overdrive gears.
Granted though... most all of the 8L90 gears are carefully picked to give the best results on the EPA controlled dyno test
With the torque coming on so quickly (at lower RPM range) with these direct injection engines... it would require less gears in a tranny to get pure straight-line performance... not more. Un-necessary shifting adds time.
Readers Digest version:
complete article here:
http://corvettec7fiasco.blogspot.com...peed-8l90.html
The C6 A6; 5th and 6th (the last two) were overdrives.
in the A8, same... the last two (7th and 8th) are the only overdrive gears.
Granted though... most all of the 8L90 gears are carefully picked to give the best results on the EPA controlled dyno test
With the torque coming on so quickly (at lower RPM range) with these direct injection engines... it would require less gears in a tranny to get pure straight-line performance... not more. Un-necessary shifting adds time.
Readers Digest version:
the new 8 speed transmission gearing is set up in a way that allows for 0-60 run to be accomplished right before red line in second gear, with the max speed in 2nd gear being either 65 mph (Z51) or 70 mph (non Z51)....
With the new transmission, the 0-60 time will be achieved at the top of the max torque and right before it drops abruptly as it approaches the 6500 rpm redline...
However, there is a problem here, with regards to quarter mile runs. Unlike the current 6 speed transmission, the 8 speed version will need the fifth gear (two extra shifts compared to the A6) to achieve the quarter mile trap speed. Currently, the quarter mile runs are completed in THIRD gear. The difference of two extra shifts will truly disclose the actual improvement (if any) ... in the quarter mile...
If indeed, the quarter mile time will improve for 2015 Stingray... then Juechter and the rest of his team will indeed have a valid claim; but this has to be demonstrated by the quarter mile times, not by 0-60 times alone...
With the new transmission, the 0-60 time will be achieved at the top of the max torque and right before it drops abruptly as it approaches the 6500 rpm redline...
However, there is a problem here, with regards to quarter mile runs. Unlike the current 6 speed transmission, the 8 speed version will need the fifth gear (two extra shifts compared to the A6) to achieve the quarter mile trap speed. Currently, the quarter mile runs are completed in THIRD gear. The difference of two extra shifts will truly disclose the actual improvement (if any) ... in the quarter mile...
If indeed, the quarter mile time will improve for 2015 Stingray... then Juechter and the rest of his team will indeed have a valid claim; but this has to be demonstrated by the quarter mile times, not by 0-60 times alone...
http://corvettec7fiasco.blogspot.com...peed-8l90.html
Last edited by Mike Mercury; Jul 15, 2014 at 09:21 AM.
Melting Slicks
Joined: Jul 2006
Posts: 2,090
Likes: 51
From: Georgetown TX
Why do you need another overdrive gear on a 460 hp car that is getting reports of 32mpg??
Last edited by beepster; Jul 15, 2014 at 09:39 AM.
