Diff ratio

[AshG]

Originally Posted by snapper

The type 9 whilst better ratios than an MT75 is still not ideal
1st to low as is second 5th to long
The ideal is a V6 box with a long first and a 3.9 diff
Tyres add to the ratio mix but in essence you want to get 1st and 4th close enough to give 40+ mph in 1st and about 125 in 4th
5th can be for long cruises
Extra rev range for the engine helps close the gap

125 in 4th yeah good luck. anything less than 200bhp in a 7 and you want 4th geared for 90-95 and 5 geard for about 125-130. look at the ratios in a caterham for reference, their ratios are about as spot on as it gets for a 7. aero is a huge limiting factor on a 7. mine is a fire breathing 2.0 turbo running over 200bhp and it will only do 145 flat out which in a 7 is bloomin quick and a total assault on your body and senses, the other issue is that around 125ish the steering gets very light an twitchy on the mass majority of 7's