View single post by Mark Rosenbaum

Posted: 08-26-2005 03:16 pm

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Mark Rosenbaum

Joined:	03-12-2005
Location:	Kingman, Arizona USA
Posts:	532
Status:	Offline

I agree with Judson, the stock 4-speed has excellent ratios. The ideal in most applications is to have the ratio between adjacent gears equal to the ratio between engine rpm at peak power and engine rpm at peak torque. For the stock JH, with its power peak at 6500 rpm and its torque peak at 4800 rpm, this ratio is 1.354 to 1.

Playing with the numbers (a scurrilous vice, to be sure) we find that a JH would be best served by a 5-speed with ratios as follows:
Gear     Theory
5         1.00 : 1
4         1.35 : 1
3         1.83 : 1
2         2.48 : 1
1         3.36 : 1

As you can see, for the top three gears, the stock 4-speed comes quite close to this theoretical ideal.