m52 setup questions

Moderator: martauto

matt86
E30 Zone Addict
E30 Zone Addict
Posts: 2468
Joined: Thu Jan 19, 2012 11:00 pm
Location: "The Cotswolds" Stroud, Gloucestershire

Post Sat Mar 28, 2015 11:32 pm

I have a m52 engine with m42 gearbox, clutch and flywheel.

Was wondering what diff and prop I should use as I don't understand ratios. I want good acceleration, not bothered about fuel consumption, but also don't want something that is high revving on the motorway.

Would a m40 or a m42 prop and diff be best and what ratio?

Thanks
User avatar
Brianmoooore
E30 Zone Team Member
E30 Zone Team Member
Posts: 49359
Joined: Mon Jan 10, 2005 11:00 pm

Post Sun Mar 29, 2015 10:30 am

If you've used your existing diff., then the revs. for a given speed will be exactly the same as they were before the swap.
If you want it to rev. less for a given speed, then you need a numerically lower ratio that whatever you have now.
DanThe
E30 Zone Team Member
E30 Zone Team Member
Posts: 28649
Joined: Sat Sep 10, 2005 11:00 pm
Location: Staffs

Post Sun Mar 29, 2015 11:00 am

Most use a 3.64 with the M42 box
matt86
E30 Zone Addict
E30 Zone Addict
Posts: 2468
Joined: Thu Jan 19, 2012 11:00 pm
Location: "The Cotswolds" Stroud, Gloucestershire

Post Sun Mar 29, 2015 11:06 am

Thanks Brian and Dan.

One more question will the existing m10 prop and differntial mate up with the m42 gearbox. I think I was told they wont, but will with a m30 conversion due to a different bolt pattern on the gearbox housing
DanThe
E30 Zone Team Member
E30 Zone Team Member
Posts: 28649
Joined: Sat Sep 10, 2005 11:00 pm
Location: Staffs

Post Sun Mar 29, 2015 11:27 am

320i prop is normally used