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Author Topic:   Trans vs rear ratios - torque?
racinfool
Dirt Full Roller

Total posts: 53
posted December 08, 2005 05:23 PM  
Being the same overall ratio (trans x rear) is there any difference in torque off the corners in having the trans ratio vs the rear gear ratios higher or lower? ... if so, why??

In another words, if your overall ratio you want to acheive is 5.13, ... would it be better to have a 1.00 trans (3rd) and 5.13 rear gear = 5.13 overall ratio -- or -- 1.50 trans (2nd) and 3.42 rear gear = 5.13 overall ratio????

Maybe it make no difference.?.

Thanks

racer17j
Dirt Forum Champ
Total posts: 5473
posted December 08, 2005 06:28 PM  
I agree with 17j, if at all reasonably possible run high gear. The transmission is most efficient in high, there are less parts in motion so there's less friction and less wear. But of course if you are limited to a Chevy rear and you are racing on a bull-ring you've got no choice.

backwoodsracer
Dirt Forum Racer

Total posts: 90
posted December 08, 2005 08:29 PM  
Dont forget the moron tech guy at some tracks that sets a gear limit in the spirit of saving racers money.At my track its 4.11 we can also run a 9-inch rear which has limitles ratios and are low cost so when i asked why 4.11 he said the stock housing can only hold a 4.56 and it wouldnt be fair to the guys that couldnt afford a 9-inch.My thought is why even allow a 9-inch at all? 1-1 is better if you can run it but if you cant I would keep a close eye on your trans and run a good synthetic oil in it.

keyz28
Dirt Roller

Total posts: 5
posted December 10, 2005 12:47 AM  
I've been wondering about the loss of torque multiplication from 2nd to drive for a few years due to a drag racing experience. What I had was an unknown problem that only showed when shifted into third. The engine just layed down in drive while pulling good in 1st and 2nd. Turns out it had a wrist pin seizing up and what I guessed was due to torque multiplication did not show itself in 1-2. If thats the case 2nd would be better. Any thoughts?

wetwolfone
Dirt Full Roller

Total posts: 53
posted December 10, 2005 07:25 AM  
Theoretically, it is more efficient to run high gear. Don't really think it makes a lot of difference on the track though. we have the 4.11/no ford 9" rule, so I run 2.56 in low and it seems to work fine.


Mark Wakefeld
Dirt Roller

Total posts: 20
posted December 10, 2005 08:01 AM  
wrong,,,,

A stock saginaw trans turns every gear inside it in high.


nothing is sitting idle not even the countershaft on the side of the case.

akadirtracer7
Dirt Freak

Total posts: 220
posted December 10, 2005 08:58 AM  
Keyz28 the torque converter multiplies torque to.That might have played into what you was feeling.That is if you are running an automatic.I always prefer to run the final drive ratio I want and the trans 1-1.I look at it like the more parts you got to turn the more you got to break.

ARMallardSlayer
Dirt Maniac

Total posts: 183
posted December 10, 2005 01:57 PM  
Using the rearend to gear your car and running your tranny in high is the best way to go.

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