tranny questions
jdrumstik
03-16-2004, 01:24 PM
I have three questions and will try to not ramble like I usually do, by the way this is in assosiation with a big block El Camino with a tremec over drive manual
What is a posi traction differential, I alwasy thought posi was just slang for differential, but I am beginning to tink htat it is something else.
figuring a diff. ratio. Every one tells me to get a 4.56, or a 4.11. But they are reffering to drag cars, and the large slicks increase the drive ratio, so they need a real low differential to try to counter that. So assuming I am using stock tires and have a redline of lets say 6,000 rpm, and a final drive of .76, then what kind of ratio do I want to hit 150mph?
last, I would prefer to get an old 6 speed vette, that boast s a 454. Would it be possible to make the psedal linkage and pedals out of the vette fit in the El camino with little fabrication, and a custom drive shaft doesn't cost to much right?
p.s. most trannys are rated for under 450ibs tq. what do you do if you are more in the 500 range? risk it?
What is a posi traction differential, I alwasy thought posi was just slang for differential, but I am beginning to tink htat it is something else.
figuring a diff. ratio. Every one tells me to get a 4.56, or a 4.11. But they are reffering to drag cars, and the large slicks increase the drive ratio, so they need a real low differential to try to counter that. So assuming I am using stock tires and have a redline of lets say 6,000 rpm, and a final drive of .76, then what kind of ratio do I want to hit 150mph?
last, I would prefer to get an old 6 speed vette, that boast s a 454. Would it be possible to make the psedal linkage and pedals out of the vette fit in the El camino with little fabrication, and a custom drive shaft doesn't cost to much right?
p.s. most trannys are rated for under 450ibs tq. what do you do if you are more in the 500 range? risk it?
AMC360Concord
03-30-2004, 02:10 AM
Hey man
Most conventional axles only power one wheel. On these old cars, if that main drive wheel let say, is stuck on a patch of ice, the opposite wheel will not spin. The non dominant wheel will not begin to turn until the main wheel does.
On a positraction axle, both wheels are driven. On that ice patch, the other wheel will grip and the car will be on its way. Positraction is nice to have, especially in poor weather.
SureGrip and TwinGrip are other names for the same thing.
To see if you have a posi rear, jack up one of the rear wheels, so that one is in the air, and one on the ground. Try to turn the lifted wheel with the car in gear (no ebrake). If the wheel will not move, the you have a posi axle.
As for your ratio, it depends on the diameter of your tires. For say a 27 inch diameter, with the overdrive engaged. You will top out at 6000 rpm at around 150 mph with a 4.11 axle. (there is a long long complex mathematical formula to calculate this) There are some websites with racing calculators to do the work for you.
As for the transmission with 500 ft/lb i dont know of any overdrive transmissions that could handle that. A GM TH-400 could do the job, but that lacks the overdrive gear. I would ask a transmssion specialist about that one. Goodluck!!
Most conventional axles only power one wheel. On these old cars, if that main drive wheel let say, is stuck on a patch of ice, the opposite wheel will not spin. The non dominant wheel will not begin to turn until the main wheel does.
On a positraction axle, both wheels are driven. On that ice patch, the other wheel will grip and the car will be on its way. Positraction is nice to have, especially in poor weather.
SureGrip and TwinGrip are other names for the same thing.
To see if you have a posi rear, jack up one of the rear wheels, so that one is in the air, and one on the ground. Try to turn the lifted wheel with the car in gear (no ebrake). If the wheel will not move, the you have a posi axle.
As for your ratio, it depends on the diameter of your tires. For say a 27 inch diameter, with the overdrive engaged. You will top out at 6000 rpm at around 150 mph with a 4.11 axle. (there is a long long complex mathematical formula to calculate this) There are some websites with racing calculators to do the work for you.
As for the transmission with 500 ft/lb i dont know of any overdrive transmissions that could handle that. A GM TH-400 could do the job, but that lacks the overdrive gear. I would ask a transmssion specialist about that one. Goodluck!!
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