Projects Rear end

Hi,
i run this car atsebring and this is not a trick question. I have a v/6 mustang with a 3.31 rear end and at 4500 rpm i am turning abt 90 mph. If i where to drop it to a3.08 about what speed do you think i would be turning at 4500 rpm.

Thanks
for all your help but i can not figure it oout nor do i know how.

Sp1ke

 

Quick answer- 83.7 mph. You will be slower with the gear change.

3.31. 3.08
---- = -----
90 X


Cross multiply and solve for X.

 

About 4300 rpm

 

Not quite, mph should be higher. Looks to me like 96.7 MPH.
Larry T

 

Larry,

I see now what happened. My math was 100% correct -- the formula was not correct. The setup should have been a f(x) style equation, not a ratio. Such as the following.

(Initial gear ratio) (speed) = (final gear ratio) (speed)
(3.31) (90) = (3.08) (x)
297.9 = 3.08x
96.7 = x

So Larry was correct the first time. I stand corrected.