S6-37 6mt swap info (broken off from junk yard thread)

[George Hill]

Don't people plug and play the non M 5mt into M3s for track use? I've never heard of any input spine shaft issue for that (though admittedly never cared enough to look into it), and I'd have to imagine that's the same in the 5mt and 6mt.

... better not do any power mods of your S54. S6-37 is rated for 273 ft lbs of torque. Stock S54 comes with 269 ft lbs!

No they don't, you cannot remove a 420g and replace it with a ZF320 with no other mods. Basic rule is the transmission dictates the clutch (and flywheel), crossmember and shifter. Driveshafts have a couple variables because all of the transmissions are different in length/guibo size.

And that torque rating isn't a glass ceiling. IDK what it actually means but if that were the case all the turbo ZHPs would have blown up transmissions... think about how many SC/turbo S54/S52s are making well over 420nm and running 420g or ZF320s.

If you are concerned about it though then put in an S6-53 from an N54 335i.

[Obioban]

bigjae46 Obioban

The S6-37 is such a good transmission ESPECIALLY compared to a 420g. I approve of swapping them in place of the 420g. To make the swap you would use everything from the E46 330 setup (clutch/flywheel and shifter). You'd probably need a custom drive shaft to work with the M3 diff though.

IIRC the difference in the M vs Non-M is the input shaft spline count, but I could be wrong.

Don't people plug and play the non M 5mt into M3s for track use? I've never heard of any input spine shaft issue for that (though admittedly never cared enough to look into it), and I'd have to imagine that's the same in the 5mt and 6mt.

... better not do any power mods of your S54. S6-37 is rated for 273 ft lbs of torque. Stock S54 comes with 269 ft lbs!

[George Hill]

bigjae46 Obioban

The S6-37 is such a good transmission ESPECIALLY compared to a 420g. I approve of swapping them in place of the 420g. To make the swap you would use everything from the E46 330 setup (clutch/flywheel and shifter). You'd probably need a custom drive shaft to work with the M3 diff though.

IIRC the difference in the M vs Non-M is the input shaft spline count, but I could be wrong.

[bigjae46]

Per BMW, 46kg for the 420g and 43.5kg for the 37BZ:
https://www.realoem.com/bmw/enUS/par...&q=23002229721
https://www.realoem.com/bmw/enUS/par...&q=23007837983

So, 5.5 lbs. If my trans fails I might go that route, but until that time... probably sticking with the 420g.

I do notice the PN for the Z4M box doesn't include anything other than the Z4... so maybe they used some sort of custom bell housing for the Z4M?

Yeah, not worth a swap but if replacing then a BMW reman would be the route I'd go.

[Obioban]

They used it on the Z4M, so you could probably just copy whatever they did there.

…. I wonder how the weight compares…

Per BMW, 46kg for the 420g and 43.5kg for the 37BZ:
https://www.realoem.com/bmw/enUS/par...&q=23002229721
https://www.realoem.com/bmw/enUS/par...&q=23007837983

So, 5.5 lbs. If my trans fails I might go that route, but until that time... probably sticking with the 420g.

I do notice the PN for the Z4M box doesn't include anything other than the Z4... so maybe they used some sort of custom bell housing for the Z4M?

[Obioban]

The ZF 6 speed in the non-Ms shift far better than the rubbery 420g. I think the input shaft is slightly shorter...so would it bolt onto an S54 with the non-M flywheel?

They used it on the Z4M, so you could probably just copy whatever they did there.

…. I wonder how the weight compares…

[bigjae46]

A ZHP? Now that's a good score! Those transmissions are $$$$.

The ZF 6 speed in the non-Ms shift far better than the rubbery 420g. I think the input shaft is slightly shorter...so would it bolt onto an S54 with the non-M flywheel?

[liam821]

usdmej.... Yes

A ZHP? Now that's a good score! Those transmissions are $$$$.

[George Hill]

usdmej.... Yes