at 90mph my cars only doing 3000rpm (1.8t cec) do you think i should go with some smaller wheels to lower the ratio a bit ? currenty on 16" so a lower profile really isnt anygood as i'm running 205 45 16 already.

What ratio is your diff? You might have a 3.14 which you can probably sell for hundreds to someone building a BEC.

3.62 lsd using the nissan gear box which isnt that far from the type9 ratio wise.

[Edited on 10/7/07 by graememk]

get a 3.92 dif or 13" wheels should help. ps get the quaife gear calc aswell, should help your choice.

[Edited on 10/7/07 by ned]

Moving to a 185 60 13 wheel/tyre

That would only increase the revs per mile from 867 to 928 (about 7%)

Sounds like a new diff required (or a new rev counter )

So will it do 180Mph at 6000 rpm?