BMW's M diff lock similar to our VLSD?

Pharmacist · 12-24-2011, 02:34 PM

Is the lsd on bmw m cars similar to our vlsd????????????????????

Auto Tech: BMW Variable M-differential lock - Autos.ca

Quote:

The Variable M-differential lock can provide traction advantages even when one wheel is on glare ice. The factor that determines torque transfer is the speed differential of the drive wheels. As soon as one wheel starts to spin, torque is transferred to the other wheel. The greater the speed difference, the more torque is transferred.

To accomplish this, BMW is using a sheer pump located inside the differential. One drive wheel is connected to one part of the pump and the other wheel is connected to the other part. As wheel speeds differ, the pump provides a variable pressure that applies multi-disc clutches preventing the spinning wheel from turning faster than the other wheel.

The pump is a sealed unit that uses high viscosity silicone oil between two sheer discs. As soon as the two sheer discs turn at different rates, the silicone oil is sheered by the grooves in the sheer plates and this generates a pressure dependent on the speed differential of the two plates. Thus, a variable differential lock effect is achieved. As soon as the two wheels are turning the same speed, the pressure of the sheer plates decreases and the differential unlocks.

kenchan · 12-24-2011, 05:13 PM

not sure but sounds good but also sounds like something that will break on bimmers...

Mt Tam I am · 12-25-2011, 11:03 AM

I assume OP is looking at BMW's since his Z got crunched by an idiot.

Red__Zed · 12-25-2011, 11:57 AM

No. It's a variable lock up clutch type that uses viscous fluid to run the shear pump, doesn't behave similar to a VLSD at all

chuckhumprey · 01-26-2012, 09:43 PM

Quote:

Originally Posted by Pharmacist

Is the lsd on bmw m cars similar to our vlsd????????????????????

Auto Tech: BMW Variable M-differential lock - Autos.ca BMW parts

Agree on Red. It might just a mess for BMW. The system works actually though the differential lock is having few issues such as low wheel traction. perhaps its about time, they would realized this and end up with the remedy.

12-25-2011, 11:03 AM	#3 (permalink)
Mt Tam I am A True Z Fanatic Join Date: Jun 2010 Location: California Posts: 10,709 Drives: 370Z T/S/N 6MT & XKE Rep Power: 3843	I assume OP is looking at BMW's since his Z got crunched by an idiot. __________________ "Does the carpet match the drapes? NO!!! I don't date bald women." Nissan Motorsports 34R Oil Cooler. Stillen CBE. Hotchkis Sport Sway Bars. KW Variant 3 Coilover System. Stillen Gen3 CAI. Michelin Pilot Super Sport. Stillen Brake Ducts. Carbotech™ XP10/XP8 Pads. Z1 Front Rotors. Z1 Stainless Brake Lines. Two degrees of camber

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12-24-2011, 05:13 PM	#2 (permalink)
kenchan A True Z Fanatic Join Date: Aug 2009 Location: N/A Posts: 76,801 Drives: N/A Rep Power: 141521	not sure but sounds good but also sounds like something that will break on bimmers...

12-25-2011, 11:57 AM	#4 (permalink)
Red__Zed A True Z Fanatic Join Date: Jul 2010 Location: window seat Posts: 28,940 Drives: Mostly on two wheels Rep Power: 120	No. It's a variable lock up clutch type that uses viscous fluid to run the shear pump, doesn't behave similar to a VLSD at all