A greater number doesn't always mean stronger.
Ummm.... in this case.... yes... the numbers do mean something.
They are Getrag's nominal gearbox torque handling ability in Nm.
They are allways overbuilt.... so the actual breaking point of the tranny is way higher than the rating.
Conversion from Nm to ftlb is... 1 Newton Meter = 0.737 562 147 pound foot
So... the F16/D16 is rated for 160Nm which is 118 lbft
This tranny should handle around 250lbft of torque or more but it will snap if you are not carefull.... with drag slicks.... perhaps derate that to something closer to 225lbft of torque
The D20/F20 is rated for 200Nm which is 148lbft
This tranny should handle 300lbft to 400lbft of torque depending on a number of factors.... again... derate this for Drag slicks
The 6spd F28 is rated for 280Nm which is 207lbft
These transmissions have been able to handle 500lbft of torque or more and it's one of the most widely used transmissions for Rally racing Opels.
The 6spd F40 is rated for 400Nm which is 295lbft
It should be similar to the F28.... and should handle 500lbft of torque without too much trouble.
The F40 is available in the Saab 9-3 6spd and Pontiac G6 6Spd.
Now... before you get excited.... this tranny has multiple bell housings.... the one for the 3.9L V6 in the G6 won't fit our engine.
I haven't been able to pin down the Saab bell housing shape but odds are it also does not fit.
The good news is that the F40 is also used on the iron block 2.0L Turbo ( Z20LET ) in Europe/UK so that means there is a bell housing that will fit our engines!
I am currently researching this tranny.... and I will let you guys know what I come up with.
Oh.... just so you know.... this tranny recieved very good reviews for it's smooth and quick action..... it's a tripple shaft design so it's very light and very strong.
Currently there is a Fiero performance shop building an LS2 V8 6spd conversion kit using the F40.... so if it can handle the massively powerfull LS2 engine it can certainly handle what ever we can throw at it.
I will be purchasing one or perhaps two of them once I get the bell housing issue sorted out.
I may even simply purchase the correct bell housing from Europe and convert a North american F40 for use with my vehicles.