official gear ration of the new 8l90
01-13-2014, 11:15 AM
#1
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official gear ration of the new 8l90
The gear ratios for the 8L90 are:
1st: 4.56
2nd: 2.97
3rd: 2.08
4th: 1.69
5th: 1.27
6th: 1.00
7th: .85
8th: .65
Reverse 3.82
How it will perform on this set of ratio ?
1st: 4.56
2nd: 2.97
3rd: 2.08
4th: 1.69
5th: 1.27
6th: 1.00
7th: .85
8th: .65
Reverse 3.82
How it will perform on this set of ratio ?
01-13-2014, 06:24 PM
#3
Race Director
If that is right and it shifts as fast as they are saying this thing is gonna moooooooove 
01-13-2014, 07:03 PM
#4
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Location: Hicksville NY
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I love the new gearing and I think the car will be a beast with this tranny.
1st to 2nd 35% rpm drop
2nd to 3rd 30% rpm drop
3rd to 4th 19% rpm drop
4th to 5th 25% rpm drop
5th to 6th 21% rpm drop.
If this tranny can shift as fast as it's claimed to be able to with such small drops in rpm I think the new z will be a rocket.
1st to 2nd 35% rpm drop
2nd to 3rd 30% rpm drop
3rd to 4th 19% rpm drop
4th to 5th 25% rpm drop
5th to 6th 21% rpm drop.
If this tranny can shift as fast as it's claimed to be able to with such small drops in rpm I think the new z will be a rocket.
01-13-2014, 07:10 PM
#5
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not necessarily, my old 86 monte carlo had a 2.41 rear with a .67 o.d. it did very well on the highway at 85 mph in terms of gas mileage and it could maintain that speed with a crappy 305 that probably had 150 hp. the z06 with a p.d. supercharger will be able to pull fine with that gearing.
01-13-2014, 07:14 PM
#6
Team Owner
In 7th gear the manual transmission has a .42:1 ratio and a 3.42:1 rear gear for a 1.44:1 final ratio.
With the A8 and the .65:1 ratio in 8th gear and the 2.56:1 rear gear, you have a 1.66:1 final ratio.
The low end torque of the LT4 can handle the 1.66:1 final ratio even better than the manual transmission's 1.44:1 final ratio with the LT1's much lower torque.
Last edited by JoesC5; 01-13-2014 at 07:16 PM.
01-13-2014, 07:26 PM
#7
Pro
Assuming a 2.73 rear end like the Auto Z51, top speed in each gear is:
Gear Ratio MPH
1.... 4.56... 39.88
2.... 2.97... 61.23
3.... 2.08... 87.43
4.... 1.69... 107.61
5.... 1.27... 143.20
6.... 1.00... 181.86
7.... 0.85... 213.96
8.... 0.65... 279.79
Gear Ratio MPH
1.... 4.56... 39.88
2.... 2.97... 61.23
3.... 2.08... 87.43
4.... 1.69... 107.61
5.... 1.27... 143.20
6.... 1.00... 181.86
7.... 0.85... 213.96
8.... 0.65... 279.79
01-13-2014, 07:31 PM
#8
Team Owner
Want to laugh your *** off. Go to you tube and look at the video of the interview at the 2013 auto show in Detroit a year ago where they showed the C7 stingray for the first time,with the Corvette's chief engineer where he discusses the A6 and why the Corvette doesn't need a heavier, weaker, less reliable, more costlier A8 transmission. Starting at 10.30. Hilarious.
Last edited by JoesC5; 01-13-2014 at 07:34 PM.
01-13-2014, 07:46 PM
#9
Instructor
Are you using 6,500 rpm as the maximum? I guess that is the new car's redline?
01-13-2014, 08:29 PM
#10
Team Owner
I'm betting the 2.56 will be the only gear available on the Z06 A8. They need the 2.56 to help with the fuel mileage and to keep the car away from the gas guzzler tax.
01-13-2014, 08:48 PM
#11
Pro
Adjusting to 2.56 and 6,500 rpm, the numbers are:
Gear Ratio MPH
1... 4.56... 41.89
2... 2.97... 64.31
3... 2.08... 91.83
4... 1.69... 113.02
5... 1.27... 150.39
6... 1.00... 191.00
7... 0.85... 224.71
8... 0.65... 293.85
Last edited by Stunt; 01-13-2014 at 08:52 PM.
01-13-2014, 09:15 PM
#12
Le Mans Master
No gotcha
Want to laugh your *** off. Go to you tube and look at the video of the interview at the 2013 auto show in Detroit a year ago where they showed the C7 stingray for the first time,with the Corvette's chief engineer where he discusses the A6 and why the Corvette doesn't need a heavier, weaker, less reliable, more costlier A8 transmission. Starting at 10.30. Hilarious.
This is what he actually said:
"I don't know what's happening in Toledo, but I saw the rumors about the 8-speed transmission. It was an Aisin transmission, a Japanese-supplied transmission, but that transmission does not fit in a Corvette. There is no transmission that plugs-and-plays with the Corvette's huge amount of torque. We really couldn't find an 8-speed transmisison.
"And to be honest, perfectly honest, the number of speeds is turning into sort of a marketing arms race, with everybody wanting to outdo each other with more speeds. In 2005, when we introduced the C6, we actually introduced it with a 4-speed automatic. People will recall that. A year later we brought out a 6-speed. And internally, on the Corvette team, we struggled mightily to beat the 4-speed, the old 4-speed, for performance and fuel economy.
"Some cars need more speeds. If you have an engine that's really peaky, operates most optimally in a narrow range, you need a lot of speeds to keep it operating in that range. Corvette has a very broad torque band. You don't need to shift down 1, 2, 3, 4 gears. Most times you shift down 1 gear. You have more than enough torque to get done what you need to get done. And so, sometimes more isn't always better. So, we're very careful about that. We'll continue looking at whether more speeds is better, because more speeds typically means more mass, more cost, more everything else - more likely to go wrong, maybe - there's a whole bunch of things you have really to be careful of before saying more is better."
He's completely upfront about the demand for more speeds being driven largely by marketing, that the 6-speed was a small improvement over the 4-speed, but that they will continue looking at gearboxes with more ratios provided that the mass, cost, etc. issues can be overcome."And to be honest, perfectly honest, the number of speeds is turning into sort of a marketing arms race, with everybody wanting to outdo each other with more speeds. In 2005, when we introduced the C6, we actually introduced it with a 4-speed automatic. People will recall that. A year later we brought out a 6-speed. And internally, on the Corvette team, we struggled mightily to beat the 4-speed, the old 4-speed, for performance and fuel economy.
"Some cars need more speeds. If you have an engine that's really peaky, operates most optimally in a narrow range, you need a lot of speeds to keep it operating in that range. Corvette has a very broad torque band. You don't need to shift down 1, 2, 3, 4 gears. Most times you shift down 1 gear. You have more than enough torque to get done what you need to get done. And so, sometimes more isn't always better. So, we're very careful about that. We'll continue looking at whether more speeds is better, because more speeds typically means more mass, more cost, more everything else - more likely to go wrong, maybe - there's a whole bunch of things you have really to be careful of before saying more is better."
There is nothing to see here.
01-13-2014, 09:20 PM
#13
not necessarily, my old 86 monte carlo had a 2.41 rear with a .67 o.d. it did very well on the highway at 85 mph in terms of gas mileage and it could maintain that speed with a crappy 305 that probably had 150 hp. the z06 with a p.d. supercharger will be able to pull fine with that gearing.
01-13-2014, 10:12 PM
#14
im presuming that since there is no mention of it, they still are not going the dct route? probably too expensive.
01-13-2014, 10:38 PM
#15
Drifting
Want to laugh your *** off. Go to you tube and look at the video of the interview at the 2013 auto show in Detroit a year ago where they showed the C7 stingray for the first time,with the Corvette's chief engineer where he discusses the A6 and why the Corvette doesn't need a heavier, weaker, less reliable, more costlier A8 transmission. Starting at 10.30. Hilarious.
01-13-2014, 10:38 PM
#16
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