Hi guys . Just finished my m52 conversion , cars been built for country lane and track work focused , went for a shorter box and a 3:91 medium case diff ..
The car goes through the gears like a motorbike which is awesome but it literally runs out of gearing at 105/110 mph , oops , slightly misjudged it, my bad .
My Diffs soon to be going for a good overhaul and I'm considering changing the crown wheel and pinion from it's 3:91 down to a 3:15 .. How much difference would it make roughly to the top end ? Are we talking 5mph or 20mph ? I know it more tech than that but just ball park .. Many thanks guys
3:91 to 3:15 ...
Moderator: martauto
- Brianmoooore
- E30 Zone Team Member

- Posts: 49358
- Joined: Mon Jan 10, 2005 11:00 pm
It would change it by 3.91/3.15 = 1.241, funnily enough.
At the revs. it now needs to go at 105 MPH, it will be going 130.3 MPH, if it can still get to those revs.
At the revs. it now needs to go at 105 MPH, it will be going 130.3 MPH, if it can still get to those revs.
-
jimbom30cab
- Tech 1 freak
- Posts: 7634
- Joined: Mon Oct 12, 2009 11:00 pm
- Location: in the garage
3:15 would be perfect for the M52, there was a thread earlier on my M52 car, Barry said it would be a good compromise.
There is a guy called Martyn Copleston on the Facebook page who can do you a graph of MPH/RPM for the gears if you want
Jim
There is a guy called Martyn Copleston on the Facebook page who can do you a graph of MPH/RPM for the gears if you want
Jim

