Hi Ulix,
The morning after.....
3.9 diff x wheel rpm = 3.9 x 911 = 3552.9
3.7 diff x wheel rpm = 3.7 x 911 = 3370.70
3.9 diff 3552.9 divided into 60,000 = 16.887mph per 1000rpm direct gear (4th)
3.7 diff 3370.7 divided into 60,000 = 17.800mph per 1000rpm direct gear (4th)
With a 3.9 diff at 6,000rpm in third gear you are travelling at 12.444mph x
6 = 74.664mph. When you shift to 4th in theory (the speed will bleed off a
bit in practice) you are still at 74.664mph but the revs are now 4,424rpm.
The rev drop is 1,611rpm.
> With a 3.7 diff at 6,000rpm in third gear you are travelling at 13.1171mph
x
> 6 = (faster than was the case with the 3.9 diff but it is the rpm that
> matters here) at 78.70mph. When you shift to 4th in theory (blah, blah,
etc)
> you are still at 78.70 but the revs are now 4,421.
> > 3.9 diff 3555.45 divided into 60,000 = 16.875mph per 1000rpm direct
gear
> (4th)
> > 3.7 diff 3370.70 divided into 60,000 = 17.800mph per 1000rpm direct
gear
> (4th)
> >
>>
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