Calling all S50B32 engines

[Demlotcrew]

Good luck!

If you dont even know what needs to be changed dont think about even jacking up the car.

[ian332isport]

I thought Ian was running a 3:91 diff and 215 tyres?

Hi Jamie,

You were correct with the tyres though. 215/40/17 all round. As previously mentioned, it's a 3.64 diff ratio.

Cheers,

Ian.

[DanThe]

The Evo diffs have a large type crown wheel, same as is used in the E46 M3, E28 M5, V8's and V12's

E46 M3 has a final drive ratio of 3.62:1

But comes at a pretty price

[GermanGorilla]

Hi,

Danny_boyKK- The E36 M3 Evo for the North American Market which
ran the M52 Engine but was short geared so as to keep 0-60 times
on a par with its European Counterpart runs a 3.91 LSD as standard.

Bit to short for a road car with 6 speed box, works very well with
the 5 speed though as it has a taller first gear.

If your thinking or swapping the CW/P in your existing diff, then find
somebody that knows what they are doing.

Setting it all up requires knowledge and experince.

If you were to do this, then I would also recommend while ''your'' in
their to change the ramp angle to 30%, and with a Grp N diff clutch of
40%, would make for a very good road set up.

Regards,

The Gorilla.

[buster]

Buster i have a mint (almost new only 1500miles) 3.25lsd if you're interested?

Or is that no good for a six speed box?

I know the m coupe has a 3.15s for the five speed (BMW could not fit the six speed into the trans tunnel)

Thanks mate but it would be too low for me.I need a 3.64 really but the 3.91 aint to bad,but it's doing approx 3100 rpm at 70mph.

[jaistanley]

Does anyone have a ratio calculator excel sheet, and the specs for the 5 speed box fitted to the MCoupé?

I used to have one round here somewhere...You could put in the specs of your gearbox, diff and tyres and it'd give you rpm and road speed in each gear. Lost it though.

From what I understand there was a crossover year for the Z3M cars whereby they went from a 3.25 to a 3.15 diff (or vise versa). Not sure if this was when they went to the M54 engine or before.

My S50B32, gearbox and diff came from a 1997 MRoadster (same spec as an MCoupé right?) and whilst I like the sound of the low gearing, it'd be nice to see the effects of changing the diff ratio etc. If it's geared for 200 n fifth, does it accelerate like a dog in top gear? What kind of RPM at 80 in fifth when fitted with 215/40/17's (I'm going the same tyres as Ian as I know they fit and dont rub with the suspension I intend on fitting)?

Jai

[maxfield]

http://www.unixnerd.demon.co.uk/revs.html

[buster]

http://www.unixnerd.demon.co.uk/revs.html

thats good but how do i find out my gear ratios to enter into it.

[maxfield]

http://www.supercars.net/cars/2405.html

http://www.supercars.net/cars/2406.html

[jaistanley]

That site quotes the ratios for the 5 speed gearbox as the same as the 6 speed, except for the inclusion of a 0.81 6th. Also says the final drive is 3.15 on both... Is this correct?

I googled 'MCoupé gear ratios' and came up with the same ratios for the 5 speed I have.

Looks like all they have wrong is the final drive then.... Correct?

Jai