How many are you waiting for the 10 speed?
Racer
Joined: Oct 2015
Posts: 434
Likes: 121
From: Allen Tx
I don't understand the original post, or reasoning very well. Even if it fit.....why would anyone wait on driving this car a couple of years? Then they may never do it so you might as wellwait for the c8..since the C7 is old news......but you won't want the first year model so you wait for the electric model.....it's a marginal difference so I wouldn't let the model get older and older......jump in and live a little
Thread Starter
Burning Brakes
Joined: Nov 2016
Posts: 774
Likes: 91
Look at the stated fact about size right under the color drawing cutout,
The new 10-speed automatic has essentially the same physical dimensions as existing 6- and 8-speed counterparts. It features a gun-drilled main shaft.
https://saemobilus.sae.org/feature/16AUTD07_02
The new 10-speed automatic has essentially the same physical dimensions as existing 6- and 8-speed counterparts. It features a gun-drilled main shaft.
https://saemobilus.sae.org/feature/16AUTD07_02
Race Director
Joined: Oct 2008
Posts: 16,670
Likes: 7,738
From: NJ
Because HP is what accelerates a car and the power band of the LT4 is narrow. The M7 and A8 are close ratio transmissions to keep the LT4 in its power band, more gears always benefit engines with narrow power bands and close ratio transmissions. The M7 loses to the A8 in a quarter mile/stoplight-to-stoplight race because 1st gear in the M7 is very low numerically...it was forced into that because of the close ratio gear set used. The A8 loses to the M7 in roll races/road races because the 4th-5th shift causes a large drop in RPM just at the speed where it hurts the most...as you increase speed, the gear ratios need to get closer and closer.
The A10 has a numerically high 1st gear similar to the A8 and 10th gear is slightly lower numerically than 8th gear in the A8. That means the gears are closer together and the huge drop in RPM between 4th and 5th gear are gone. The performance with the A10 would be significantly better than the A8 or the M7 no matter what race you're participating in.
The A10 has a numerically high 1st gear similar to the A8 and 10th gear is slightly lower numerically than 8th gear in the A8. That means the gears are closer together and the huge drop in RPM between 4th and 5th gear are gone. The performance with the A10 would be significantly better than the A8 or the M7 no matter what race you're participating in.
100% more gears.
8 to a 10 spd. Is a 25% increase. Which is not much given the spreads. The 650/650 make it even less so unless you're talking about drag racing and looking for .05 improvement and maybe a mph.
think of 8spd like a 3400 stall and the 10 like a 3600. Sire it'll be quicker but not earth shattering.
gm having enough trouble with 8 gears. Let's see how this plays out. Imo same size casing means even smaller parts to allow for more gears. That's a scary enough proposition.
and why didn't they offer it in the ZL1 1LE?
Melting Slicks
Joined: Dec 2007
Posts: 2,886
Likes: 1,255
From: Carmel CA
Because HP is what accelerates a car and the power band of the LT4 is narrow. The M7 and A8 are close ratio transmissions to keep the LT4 in its power band, more gears always benefit engines with narrow power bands and close ratio transmissions. The M7 loses to the A8 in a quarter mile/stoplight-to-stoplight race because 1st gear in the M7 is very low numerically...it was forced into that because of the close ratio gear set used. The A8 loses to the M7 in roll races/road races because the 4th-5th shift causes a large drop in RPM just at the speed where it hurts the most...as you increase speed, the gear ratios need to get closer and closer.
The A10 has a numerically high 1st gear similar to the A8 and 10th gear is slightly lower numerically than 8th gear in the A8. That means the gears are closer together and the huge drop in RPM between 4th and 5th gear are gone. The performance with the A10 would be significantly better than the A8 or the M7 no matter what race you're participating in.
The A10 has a numerically high 1st gear similar to the A8 and 10th gear is slightly lower numerically than 8th gear in the A8. That means the gears are closer together and the huge drop in RPM between 4th and 5th gear are gone. The performance with the A10 would be significantly better than the A8 or the M7 no matter what race you're participating in.
http://www.chevrolet.com/performance...gines/lt4.html
http://www.lsxmag.com/news/lt4-engin...50-horsepower/
Last edited by skank; Mar 27, 2017 at 11:25 AM.
Drifting
Joined: Jan 2006
Posts: 1,498
Likes: 166
From: Metro Detroit - miss FL
I'm not. Once I get bored with my Z06, I'll be done with Corvettes. Kind of like the old TV show "Eight is Enough", I'm on my 8th Corvette and it will be replaced with something yet to be determined.
Drifting
Joined: Oct 2006
Posts: 1,372
Likes: 311
From: Bristol, VT
Le Mans Master
Joined: Jul 2005
Posts: 5,328
Likes: 405
Narrow Power band on a LT4 ???? It has 457 ft/lbs of torque at throttle tip in and is broad all the way up to it's max of 650 ft/lbs. That is massive !! The Ferrari 458 has 398 ft/lbs of torque at it's peak. The Ferrari engine would be considered narrow under your analysis.
http://www.chevrolet.com/performance...gines/lt4.html
http://www.lsxmag.com/news/lt4-engin...50-horsepower/
http://www.chevrolet.com/performance...gines/lt4.html
http://www.lsxmag.com/news/lt4-engin...50-horsepower/
If you believe "massive" torque is the best, you need to swap a Duramax diesel into your Z06...it has 800 LB-FT of torque!
Last edited by glass slipper; Mar 28, 2017 at 03:32 PM.
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Le Mans Master
Joined: Jul 2005
Posts: 5,328
Likes: 405
true when jumping from a 4spd to an 8spd.
100% more gears.
8 to a 10 spd. Is a 25% increase. Which is not much given the spreads. The 650/650 make it even less so unless you're talking about drag racing and looking for .05 improvement and maybe a mph.
think of 8spd like a 3400 stall and the 10 like a 3600. Sire it'll be quicker but not earth shattering.
gm having enough trouble with 8 gears. Let's see how this plays out. Imo same size casing means even smaller parts to allow for more gears. That's a scary enough proposition.
and why didn't they offer it in the ZL1 1LE?
100% more gears.
8 to a 10 spd. Is a 25% increase. Which is not much given the spreads. The 650/650 make it even less so unless you're talking about drag racing and looking for .05 improvement and maybe a mph.
think of 8spd like a 3400 stall and the 10 like a 3600. Sire it'll be quicker but not earth shattering.
gm having enough trouble with 8 gears. Let's see how this plays out. Imo same size casing means even smaller parts to allow for more gears. That's a scary enough proposition.
and why didn't they offer it in the ZL1 1LE?
As CPhelps stated, the A10 uses the same number of gear sets as the A8 and one extra clutch pack. It has two sets of "nested" clutch packs to provide more room for the additional clutch pack, it will be just as strong if not stronger than the A8. I haven't heard of any problems with "structural" failures of the A8, please enlighten us.
The ZL1 1LE is a track oriented car with low production numbers and a market of hardcore racers who think a manual transmission is the only transmission that should be in a "race" car...it's a marketing thing. The overwhelming majority of those people would be surprised to find out they would be faster with the A10. The A10 is in the regular ZL1 which has the same 650/650 HP/Torque as the 1LE variant, what makes you think it would fail in the 1LE car and not the regular ZL1???
Thread Starter
Burning Brakes
Joined: Nov 2016
Posts: 774
Likes: 91
Don't quote me but they changed the rear/gears on the ZL1 to 331 gear instead of whats a normal ratio like 373's. I don't know as you tech guys do about what they put in automatic's so forgive me.
Now that changes the equation too but I suspect it's to do with longevity of drive train parts more than anything else.
Now that changes the equation too but I suspect it's to do with longevity of drive train parts more than anything else.
Melting Slicks
Joined: Dec 2007
Posts: 2,886
Likes: 1,255
From: Carmel CA
Melting Slicks
Joined: Dec 2007
Posts: 2,886
Likes: 1,255
From: Carmel CA
According to GM, the LT4 offers 457 lb-ft of torque just off idle and twists the crank at 625 lb-ft as quick as 2,800 rpm. It also maintains 90 percent of its peak torque from 2,500 to 5,400 rpm. For comparison, a Ferrari V12 produces 28 percent less peak torque at a much higher 6,000 rpm , even though it offers more total horsepower. The LT4 also crushes a Porsche Turbo S engine’s peak levels by 90 horsepower and 134 lb-ft of peak torque.
“Torque is the pulling power of an engine and the LT4’s abundance of it at every rpm in the engine’s speed range helps the Z06 accelerate quicker and respond nearly instantaneously,” adds Jordan Lee, chief engineer for small-block engines. “It’s the very definition of power on demand.”
“Torque is the pulling power of an engine and the LT4’s abundance of it at every rpm in the engine’s speed range helps the Z06 accelerate quicker and respond nearly instantaneously,” adds Jordan Lee, chief engineer for small-block engines. “It’s the very definition of power on demand.”
Race Director
Joined: Feb 2011
Posts: 14,740
Likes: 5,604
From: AZ
The A10 was jointly developed with Ford and GM so who knows what tradeoffs were made that may/may not allow it to fit the C7? I have heard the A10 is 1/4" longer than the A8 and that there is some minor interference to making it fit in the C7.
Do you have the length of the A10? Everything GM has put out says the A10 is the same length and fits in the same space as the A8. The problem with the A10 being used in the Corvette right now is it isn't a modular transmission, it doesn't have a separate bellhousing from the transmission case like the A4, A6, and A8. Your 4L80 conversions are made difficult because that transmission has its roots in 1960's technology with an addition using 1980's technology to add overdrive, it's physically a very large transmission. The 4L80 is an extremely strong transmission because technology in the 1960's said to make everything bigger to make it stronger, it's a very large transmission physically compared to modern day transmissions. The 4L80 is also very inefficient, they require significantly more HP to drive them than modern day transmissions.
While I hope GM makes the A10 modular, it seems they would've made it modular from the beginning to save investment in new casting molds just to put it in the Corvette. I think it's unlikely to happen but I can still hope...
While I hope GM makes the A10 modular, it seems they would've made it modular from the beginning to save investment in new casting molds just to put it in the Corvette. I think it's unlikely to happen but I can still hope...
Le Mans Master
Joined: May 2000
Posts: 8,729
Likes: 1,508
From: Redmond WA
Naturally the most acceleration will be had by operating the motor at peak horsepower (ala what a CVT would do if programmed optimally), but we have, as you not, such a broad torque curve that it doesn't seem like we should have to be shifting a great deal. There's a benefit to be had with more gears, I just don't know how significant it is.
I'd be curious to see what the difference is between the 8L90E and a powerglide but I think Desktop Dyno only supports 4 or 5 gears at most. Still might be an interesting experiment.
If you really want to see the basic math for "what generates the most acceleration at a given speed", this guy walks you through it. Ignore the trolls, stick with math! It's for CVT transmissions, but the math preamble is the same.
Last edited by davepl; Mar 29, 2017 at 12:10 PM.
Thread Starter
Burning Brakes
Joined: Nov 2016
Posts: 774
Likes: 91
According to GM, the LT4 offers 457 lb-ft of torque just off idle and twists the crank at 625 lb-ft as quick as 2,800 rpm. It also maintains 90 percent of its peak torque from 2,500 to 5,400 rpm. For comparison, a Ferrari V12 produces 28 percent less peak torque at a much higher 6,000 rpm , even though it offers more total horsepower. The LT4 also crushes a Porsche Turbo S engine’s peak levels by 90 horsepower and 134 lb-ft of peak torque.
“Torque is the pulling power of an engine and the LT4’s abundance of it at every rpm in the engine’s speed range helps the Z06 accelerate quicker and respond nearly instantaneously,” adds Jordan Lee, chief engineer for small-block engines. “It’s the very definition of power on demand.”
“Torque is the pulling power of an engine and the LT4’s abundance of it at every rpm in the engine’s speed range helps the Z06 accelerate quicker and respond nearly instantaneously,” adds Jordan Lee, chief engineer for small-block engines. “It’s the very definition of power on demand.”
Race Director
Joined: Feb 2011
Posts: 14,740
Likes: 5,604
From: AZ
