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[ANSWERED] Manual Transmission Gearing

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[ANSWERED] Manual Transmission Gearing

Old 05-04-2017, 12:53 AM
  #41  
truth.b
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Originally Posted by village idiot View Post
I agree. I'd like a slightly longer 3rd. Just a touch longer.


Nice wheeling. You seem to get on the gas good and early, but you seem to coast a lot rather than staying on the gas and braking harder.
Thanks. Yea the above clip was day 3 of 4 so I was trying to keep the tires happy. Also I'm not a 10/10ths driver in my GS because its my daily and only car so I leave alot of safety margin. I figure one day when I buy/build something with a cage & harnesses I'll probably drive full out.


Originally Posted by village idiot View Post
What recording system is that?
I'm using a very DIY system and the Post #23 in the following has all the basic details:
** Link to Detail Post about my Video/Data System **
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Old 05-04-2017, 11:42 AM
  #42  
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Originally Posted by Speednet View Post
^^^ Yeah, because Porsche always beats Corvette.
...and that has nothing to do with the topic

Originally Posted by truth.b View Post
If Corvette was designed around maximum straight line acceleration than I would agree but it is more geared towards road course work and everyday driving. Which for me short gears suck and can be more detrimental to laptimes than beneficial with the exception of automatic (DCT) trans where the shift shock between gears is controlled by a computer.
The Porsche gear ratios I shows you are just that. It's a taller 3rd gear in terms of the MPH takes it to 117 MPH and then 4th takes the car to 140 MPH and then 5th to 168 MPH.

That's better than 107 MPH in 3rd, 148 MPH in 4th, and then 5th is a mind boggling 208 MPH. Way to waste the upper gears.
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Old 05-04-2017, 12:16 PM
  #43  
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Dude, the Porsche dohc is a 3.x liter flat 6. This is a 6.2 pushrod v8. It's not exactly difficult to see why the corvette uses taller gears
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Old 05-04-2017, 12:21 PM
  #44  
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I'm kinda getting the hint that our OP posted his question just to start an argument with GM and a few others. You got your answer from Tadge as to why things were done with the manual. Stop trying to prove you know more than the fleet of engineers within team Corvette and GM Power Train. I assure you: you don't.
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Old 05-04-2017, 12:46 PM
  #45  
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Originally Posted by jvp View Post
I'm kinda getting the hint that our OP posted his question just to start an argument with GM and a few others. You got your answer from Tadge as to why things were done with the manual. Stop trying to prove you know more than the fleet of engineers within team Corvette and GM Power Train. I assure you: you don't.
no I haven't. I'm satisfied with Tadge's answer but this has brought about a good discussion. We're all going in a circle here.
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Old 05-10-2017, 05:12 PM
  #46  
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From an all-around drivability standpoint, I think the Base Stingray has the best gearing. The ratio spread from 1-5 are much closer than in the Z51 and have better falloff in rpms from gear to gear.
The Z06 gearing is just too tall for 460 hp, and is a pita on the street because the idle speed in 1st is generally too fast for traffic.
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Old 09-30-2017, 11:35 PM
  #47  
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Originally Posted by RPOC7R View Post
Per the Corvette catalog, manual transmission gear ratios are as follows:

Base Stingray - 1st - 2.664 / 2nd - 1.783 / 3rd - 1.302 / 4th - 1.000 / 5th 0.741 / 6th - 0.503 / 7th - 0.424

Z51 Stingray and Grand Sport - 1st - 2.966 / 2nd - 2.066 / 3rd - 1.426 / 4th - 1.000 / 5th 0.709 / 6th - 0.567 / 7th - 0.476

All three manual transmissions are paired with a 3.42 differential ratio.
Wish I could get a Z51 with the base gearing. At the track I find the Z51 2nd gear is too short for all but the lowest speed corners, so I end up lugging out of corners in 3rd. Would much rather have the closer spaced 2nd through 5th of the base Stingray.
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Old 10-01-2017, 12:32 PM
  #48  
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Originally Posted by G-ForceJunkie View Post
Wish I could get a Z51 with the base gearing. At the track I find the Z51 2nd gear is too short for all but the lowest speed corners, so I end up lugging out of corners in 3rd. Would much rather have the closer spaced 2nd through 5th of the base Stingray.
I totally agree. That's the same feeling I had with my 2014 Stingray Z51. I wish it had a taller 1st gear too.

If you get a chance to try a manual Z06 the better gearing is one of the first things you'll notice.
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Old 10-01-2017, 12:52 PM
  #49  
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^^^
Perhaps of interest, the "better gearing" (taller) in the Z06 is no doubt partly because of the higher torque in the Z06 engine plus IF the Z06 used the Z51/GS gearing it would exceed the max torque capability of the trans!

Per Tremic data, in 1st gear in the Z51/GS box is limited to 460 ft-lbs max engine torque. With the Z06 trans 1st gear, max 635 ft-lbs. Slightly less than the engine is capable of producing. Since tire traction is the limiting factor not an issue. The base trans is rated at 545 ft-lbs with it's 2.66:1 first gear ratio.

There is no doubt a safety factor built into those Tremic numbers so assume if you put slicks on a base Z51/GS and install an Edelbrock supercharger you won't blow the trans the first trip down the strip!

For my GS I like the shorter gears, as Tadge noted for better off the line performance!

Last edited by JerryU; 10-01-2017 at 01:02 PM.
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Old 10-01-2017, 01:50 PM
  #50  
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^^^ Understood about differences in torque, but I did not suggest that the Z51 gear box should be put into a Z06. That would be a disaster. I was saying that the gearing the Z51 was not tall enough. Which is true. In real-world Z51 driving you have to skip gears all the time.

I do not think having great off-the-line performance is good when you have to shift to second gear on your way to 60MPH.

Last edited by Speednet; 10-01-2017 at 01:51 PM.
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Old 10-01-2017, 03:13 PM
  #51  
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Originally Posted by Speednet View Post
^^^ Understood about differences in torque, but I did not suggest that the Z51 gear box should be put into a Z06. That would be a disaster. I was saying that the gearing the Z51 was not tall enough. Which is true. In real-world Z51 driving you have to skip gears all the time.

I do not think having great off-the-line performance is good when you have to shift to second gear on your way to 60MPH.
Understood you wanted to go the other way!

For 0 to 60 run, you're right. Can always do what I did when I built my '41 Oprea Coupe as a teenager. Blew 1st gear as soon as I made my first hard run after stuffing in a "51 Olds engine bored out for '55 pistons! It had was called a 3/4 cam "in the day."

The skinny tires available at the time, burned rubber talking off in 2nd until I lifted! It did have a 4.56:1 rear as the car originally came with a small 60 flathead V8! It needed that to go up hills! Took all my buddies car in the 1/4 at the time!



School Paper pic! Olds Engine Assembled from Parts in Peach Basket Without a Manual! Engine wasn't pretty but all paid or from my job in a supermarket after school! Since form follows function, looked great to me!

Last edited by JerryU; 10-01-2017 at 03:17 PM.
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Old 10-01-2017, 03:28 PM
  #52  
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That is awesome! Love the "Heavenly Heaps" title! lol
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Old 10-02-2017, 05:17 PM
  #53  
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I assume no one mentioned there was a day when GM built its own manual transmissions and if they wanted a fourth gear with a different ratio than 1-to-1, they would have built it. The sad part of this thread to me is that GM now buys so many items more-or-less off the shelf. Just the reality of the car biz today.
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Old 05-04-2018, 11:30 AM
  #54  
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Great thread !!!
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Old 09-28-2018, 07:36 PM
  #55  
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Originally Posted by quick04Z06 View Post
I assume no one mentioned there was a day when GM built its own manual transmissions.
Corvette manual transmissions haven't been made in-house since the C3. That's probably why nobody mentioned it, Mr. They-Don't-Make-'Em-Like-They-Used-To
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Old 09-29-2018, 01:12 AM
  #56  
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^^
Yep, my 1988 Vette had a 4 speed made by Doug Nash with an electrically activated overdrive in the tail shaft. Could be engaged in 2nd, 3rd and 4th providing my second 7 speed trans! The ratios were split and you activated with a button on top of the shift ****. (By the way my first 7 speed was a Dodge Colt Turbo that had a twin stick 4 speed with overdrive. Could split shift and get 8 but two were the same ratio!)

My 93 40th Anniversary Vette Trans was built by ZF who make them for Porsche, Ferrari, BMW etc. As you say, today car companies don’t make all their own parts. Heck Honda supplies engines to some.

Last edited by JerryU; 09-29-2018 at 01:16 AM.
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