Dear all,

I am new on this forum, so happy new year to all!

I would like to fit a manual transmission to a Mercedes M117 5,6 litres V8 engine that develops 300 hp at 5000 rpm and 46 kg of torque at 3750 rpm (a 286 hp M5 has 34 kg of torque and a 745 39 kg). my rear end ratio is 3,07 and my tires are 215/65/15.

It sems that Getrag gearboxes, fitted on BMWs, are the only ones rather easily available that could bear that torque, but I don't know for sure. I would rather go for a 0.81 overdrive 5th, but I don't know if I should for a 265/5 or 6? or a 280? I'm a bit lost in all these models, their gear ratios and the torque they are able to handle... So any help would be graetly appreciated!

Gael

kg is a unit of weight

kgm is a unit of torque

you rightly suppose that torque is the thing to worry about as this is what trashes gearboxes.

There is a borg-warner box that sits behind cosworth engines and the like. This will handle the torque OK.

What do you plan to use for a bell-housing?

Are you thinking of the Tremec T5 (formerly Borg Warner if I'm not wrong)?

For the bell housing, I don't know yet. If the Getrag can hold the torque, I may consider using BMW parts for flywheel, clutch plate and mechanism and bell, with an adaptator plate. For now I need to know if any of the Getrag mounted on BMWs can hold 46 Kg/m of torque...