m52 running gear options

[matt86]

What's the best option out of the m40 and m42 gearbox in terms of acceleration and long term reliability and with these two options what are the prop and differential that are required for these gearboxes.

I looked at the wiki but this doesn't mention the m40 gearbox.

I'd also like the easier fitting options so which setup is most straightforward?

Thanks

[jmc330i]

If you want long term reliability, get your self the E36 328i ZF box and suitable ratio diff.

Out of the M40 or M42 box I doubt there's much in it - they are both getrag 240 boxes with slightly different ratios iirc. A mate is using an M40 box on his M52 drifter but its far from happy - the getrag rattle is getting loud so it won't be long before the box gets changed.
For the M42 box I believe you use a 320i prop and you will need a medium case 325i diff (3.64:1 - 3.91:1). For the M40 box, I gather it's the 325i prop you need (I'm not 100% on this as we're not sure what was used in my mates car) and also the 325i diff.

If you must choose an M40/42 box, for a daily driver it would probably be ok but keep in mind if you abuse it, it won't last as long as an M20 Getrag 260 or E36 ZF box.
It's one thing to take the easiest fitting option but if you break it, you'll double your work (and money spent) as you end up pulling it apart again!

[matt86]

If you want long term reliability, get your self the E36 328i ZF box and suitable ratio diff.

Out of the M40 or M42 box I doubt there's much in it - they are both getrag 240 boxes with slightly different ratios iirc. A mate is using an M40 box on his M52 drifter but its far from happy - the getrag rattle is getting loud so it won't be long before the box gets changed.
For the M42 box I believe you use a 320i prop and you will need a medium case 325i diff (3.64:1 - 3.91:1). For the M40 box, I gather it's the 325i prop you need (I'm not 100% on this as we're not sure what was used in my mates car) and also the 325i diff.

If you must choose an M40/42 box, for a daily driver it would probably be ok but keep in mind if you abuse it, it won't last as long as an M20 Getrag 260 or E36 ZF box.
It's one thing to take the easiest fitting option but if you break it, you'll double your work (and money spent) as you end up pulling it apart again!

Thanks for all your help.

I think I may go with the m20 setup after thinking about it. Can look into upgrading to an m52 box later on.

[jmc330i]

Keep in mind you'll need a custom gearbox mount and gear linkage to run the M20 gearbox (as the M20 box is rotated when fitted to an M52), so that's one complication you don't get with the M40/42 or M52 box.