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Discussion Starter · #1 ·
Has there been any official acceleration tests or road test results for the new 8spd Automatic yet?

Mike
 

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Just my opin from knowing the industry....

The eight speed is a computer controlled tranny that is being made for all GM products and will shift faster. It's primary function, like all the other mfrs, is to help GM gets some breathing room for an increase in the CAFE number that is coming. Expect a marginal perf increase and another mpg or two. Except for some software that will be tweaked for the Vette, it is not being made for a specific Vette perf increase.
 

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Is it true it is the ZF1 gear box like on the Jaguar F-Type?


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Is it true it is the ZF1 gear box like on the Jaguar F-Type?


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No, that is not true. It was going to be for the 2014 but GM decided to design it in house and committed to making it more robust than the ZF. By all accounts they succeeded, we just need to see how it performs in the real world. BTW, I love the ZF in my Ram truck.


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Discussion Starter · #7 ·
I've read that the new 8 speed trans shifts incredibly fast and I'm sure the additional gears will improve fuel economy, but, I'm wondering if the 8 speeds will actually perform better.

Has anyone tested it?

Mike
 

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It should be the hot ticket for 1/4 mile if it does not go into limp mode when shifting as the A6 did.
 

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We'll know if GM officially changes the performance numbers shown on the Corvette's home page.
 

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I've read that the new 8 speed trans shifts incredibly fast and I'm sure the additional gears will improve fuel economy, but, I'm wondering if the 8 speeds will actually perform better.

Has anyone tested it?

Mike

The 8sp should perform a lot better. I'm guessing 0-60 in 3.6 for a coupe with 8sp auto. My daily driver is a BMW 650gc with an 8sp auto and the 4400lb car does 0-60 in 4.3. It has 445hp and 480tq; however, the gearing in the 8sp makes the car feel like it has an extra 100hp and 100tq.
 

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My wife describes it simply as two more neck snaps. :)


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The 8sp should perform a lot better. I'm guessing 0-60 in 3.6 for a coupe with 8sp auto. My daily driver is a BMW 650gc with an 8sp auto and the 4400lb car does 0-60 in 4.3. It has 445hp and 480tq; however, the gearing in the 8sp makes the car feel like it has an extra 100hp and 100tq.

Not sure it will matter much, the guy in the driver seat has more impact on times than this transmission will. Do folks realize that most 1/4 mile cars designed for drag racing use just 2 gears in their auto transmissions? I bet when the numbers come out it won't have much impact. It's really all about Cafe standards. You can buy a Jeep with a 9 spd auto, again all about Cafe standards.
 

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The "only" problem at this time is that GM don't give any C7 equipped with the A8 to make tests drivings... So all the guys who are or were interested to order one are just in the doubt and will finally order a 7MT.
For myself I was thinking that this A8 would be a possible choice for a good V8 but I was so "afraid" to read the reports of the C7 with A6 on the track that I'm not confident with what GM promises for the A8 :(
 

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We all hope. :)
 
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The 8L90 A8 is a much better in-house GM designed 8 speed
It had to handle the supercharged Z06 so it can handle up to 740 ft/lbs of torque

This is not just about CAFE as the 8L90 gearing was designed to make the lower gears output more performance to where 1.0:1 ratio is not 4th gear but 6th gear.

This is seen when I take a 2014 Stingray, a 2015 Z06 both using the manual 7 speed and
then taking the same 2015 Z06 and instead have the new 8L90 installed. ( results below)

Treating all the exactly the same using a model/simulator I set the testcase as at a drag strip

The 8L90 had a better 60 foot in time and MPH and beat the other 2 as to higher trap speeds

Test was run 5 times and the 8L90 won every time as to those 2 points and would assume with a driver tuned
to the A8 that ETs will be lower

In the end it looks like the GM 8L90 is better designed compared to the 8 speeds of ZF or the Asian design that was rumored to be used.
 

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So you tested two manuals vs. the 8sp auto.
Will you be running a 6sp vs. 8sp auto test?
 

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So you tested two manuals vs. the 8sp auto.
Will you be running a 6sp vs. 8sp auto test?
Understand he's not testing, he's running simulations. Nothing wrong with that, the simulation tool is very sophisticated, I just don't want you to think these are actual track numbers.


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So you tested two manuals vs. the 8sp auto.
Will you be running a 6sp vs. 8sp auto test?
Here is two 2014 Stingrays, only difference is 1 with older A6 and the other with new A8

Two simulation testcases results :

1 at drag strip and then on right allowed each C7 to run to maximum speeds the trannies would allow.
As seen the A8 allowed a bit higher top end

View attachment 10824
 
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