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Differential gear ratio changes

2003 - 2009, roadster, coupe, facelift
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sars
Lifer
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Re: Differential gear ratio changes

Post by sars » Wed Mar 25, 2015 10:50 pm

Jimminy wrote: Would top speed actually drop? A Z4C 3.0 si is geared to do 177 mph at 7k and with a 3.91 it would be geared for 157 mph but as its wind resistance that stops you getting to 177 mph would the mechanical advantage of a 3.91 mean it would be able to get closer to the theoretical top speed?
Top speed is governed by power and this does not change with gear ratios

Oh and great thread revival :D
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cj10jeeper
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Re: Differential gear ratio changes

Post by cj10jeeper » Wed Mar 25, 2015 10:54 pm

Sars,
You're the engineer so help me then as to why most cars a achieve top speed in one gear lower than top?
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