Is 3.25 diff ok with m50 engine and box?

[Dezzy]

Sorry i know this has been done to death but would appricate the advice. Can i use M50 engine and box with the e36 prop reverced and 3.25 diff and not be over reving at motorway speeds. Thanks

[Bavarian_Autotech]

probably the perfect ratio as iirc the E36 boxes have 1:1 5th

[Dezzy]

Thats good. Thought 3.1ish was perfect but happy days. needed to check.

[Theo]

Make sure it's a medium case type, the smaller ones can take offence to heavy launches on more powerful engines.

[Dezzy]

Its from an m3 mate will that be medium case? Pardon my thickness but how can you tell the difference. I am guessing size but will they both fit the same subframe? Cheers

[Theo]

M3 is medium case yeah. Check that the alloy backplate has 8 bolts holding it to the diff casing, not 6 like the smaller type. The fill/drain plugs are directly above/below one another on the medium case diff, whereas they aren't on the smaller type.

[Dezzy]

Thanks mate appricate the advice

[Dezzy]

The m3 diff i had the chance of has had a refurb and is not for sale now. Anyone else help

[blitz877]

ben at a-tech has an e30 m3 diff for sale i think mate

[bramley]

Make sure it's a medium case type, the smaller ones can take offence to heavy launches on more powerful engines.

Anything more to add on that Theo? I've just put a 4.45 small case lsd on my 325. Should I just avoid too many full bore starts?