On Oct 11, 2014, at 9:29 AM, Dave <[log in to unmask]> wrote:
> As regards the comment about 6th gear, I have 4.11's and have gone into the 170's in top gear. I believe that may also be possible using 3.73’s.
3.73s and 4.11s are great for drag racing but not for top speed runs which require a long period of wide open throttle operation.
The problem is the ZF S6-40 is not reliable in sixth gear if the duty cycle is long duration, high torque input. You try a 180 run where you need sixth and the trans may fail. The problem is that GM intended sixth gear to be the “gas mileage, cruising gear” and ZF engineered the transmission accordingly. Sixth was never intended to transmit full input torque for long periods.
if you want 180 mph in a ZR1, you need 3.45s and fifth gear.
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