[driftflo]

Originally Posted by Hujan

Driftflo, how do these compare to the custom differentials that you've been making?

it doenst compare against each other as these are two different parts sharing the same housing. within the rear axle pumpkin sits the final drive gearset consisting of a pinion and a ringgear. besides that there is a differential inside the pumpkin (in the case of a e92 m3 it is a viscolok lsd unit) this is screwed to the ringgear of the final drive. so you can switch the stock lsd to a clutch type one that i suggest and leave the final drive gear ratio untouched. or you can switch the gears and leave the lsd as it was before. or you can switch both.

the lsd improves traction and stability, a shorter gearset will result in more torque to the wheels. 15% shorter will give you 15% more wheeltorque (so this is what you can expect from a 3.62 compared to a 3.15 ratio in a dct car).


this is a new 4.10 final drive gearset:


and this is a clutch type lsd core:


this is the pinion installed in the pumpkin:


and this is the ringgear attached to the new lsd:


and this is how it looks when it sits inside the pumpkin:

Originally Posted by Redd

Driftlo, thanks for the info. So the bmw ms are 3.62 final drive for dct?

Any risk of over rev? Will I need a tune to get the most out of it? What's the new top speed with the 3.62?

bmw ms never raced with the e92 dct. so there is no dedicated "official suggestion" for this car. but i can source bmw motorsports gearsets with i=3.62 (or also used gearsets that are still very good but much cheaper of course). the 3.45 is also a good option but only available as used part anymore. i also have a early new non-ms 3.25 here.

i suggest 3.45 for 1M racecars, 3.62 for e92 dct racecars and 4.10 for 6mt.

if you drive a 3.62 in automatic mode you should adjust the software. i have a guy here in germany who can do it but i guess it doesnt make sense to send the DME to germany and back?! maybe there is someone in the US who can do this too. i will ask him if he has a partner in the us.

you can calculate the topspeed with a gearbox calculator. depends on the wheels you are using and so on. one customer told me, he was still able to go beyond 300kph.

Originally Posted by FogCityM3

Driftflo, is the 4.1 for the MT a rebuilt with custom gears (assuming gears are not from BMW Motorsport)?

i currently have the following parts in stock:

- 4.44 new
- 4.10 new
- 3.91 new & used
- 3.85 new & used
- 3.73 used
- 3.64 used
- 3.62 new & used
- 3.45 used
- 3.25 bmw oe new
- 3.23 used

all new gearsets are original bmw motorsports parts (except 3.25, this is an non-ms bmw part).
only the 4.10 and 4.44 feature a shotpeened surface, the others are more or less the same than the non-ms parts!
bmw gearsets are of very high quality and still quite affordable (compared to i.e. porsche gearset prices). aftermarket stuff is more expensive and often fails so i always try to usw oe parts here.