BMW HLF024 Blackline helical diff

Blackline BMW E39,E46,E53,E60,E81,E82,E83,E85,E87,E90,E92,F25 Helical LSD for vehicles fitted with 188L differential.

Suits:-

• E39 Manual - 520d, 525i, 528i, 530i, 535i, Alpina B10 3.2 (with 2.93:1 final drive), Alpina B10 3.3
  
• E39 Auto - 525d, 535i
  
• E46 Manual - 320d (with std 2.79 ratio), 323i, 328i, 330i, 330xd
  
• E46 Auto - 320d, 328i, 330xd
  
• E53 Manual Rear Diff - X5 3.0d
  
• E60 Manual - 520d, 530i
  
• E60 Auto - 525d (after 03/2007)
  
• E81 Manual - 118d
  
• E82 Manual - 120d
  
• E83 Manual Rear Axle - X3 3.0d
  
• E85 Manual - Z4 2.2i, Z4 3.0i
  
• E85 SMG - Z4 3.0i
  
• E87 Manual - 116d, 120d
  
• E87 Auto - 120d (up to 01/2007)
  
• E90 Manual - 318d, 320d (with final drives 7566218, 7566274), 325d, 330d, 325i (with final drive 7566172)
  
• E90 Auto - 318d, 320d, 325d, 330d, 330dx
  
• E92 Manual - 320d, 325d, 330d, 325i (with final drive 7519942)
  
• E92 Auto - 320d, 325d, 330d, 330dx
  
• F25 X3 SDrive 20d, Rear Axle

Helical LSD Advantages:-

• Equal rotational speed to both wheels
• Torque distributed according to traction
• Minimal service requirements - no clutches
• Quick reaction compared to viscous LSDs
• Gentle and progressive engagement, low noise
• Easily controlled power take-off and drifting
• Gears and body manufactured from 8620 alloy steel
• Direct replacement into stock differential

The Blackline helical LSD's are torque biasing, that is they distribute torque between the wheels, loading more torque towards the wheel with the best traction thus improving performance and driveabitily. Especially in low grip situations.
The helical gearing manages the distribution of friction within the LSD. When torque is applied to the helical gear system it creates force that pushes the gear into the differential body, thus creating friction. Increases of torque, increases the thrust force directly proprotional to the amount of torque. This allows the Blackline LSD to cope with considerable traction imbalance even under heavy power conditions, as would be the case on exiting a powered up corner. But at low torque conditions the LSD can differentiate quietly and smoothly, thus making the differential very suitable for normal road driving. The Blackline LSD uses the popular parallel axis helical geared configuration optimised for even load distribution. They are designed with a torque bias of 5:1 this means that if  one wheel loses traction then the wheel with the most grip can receive five times as much torque as the wheel that is slipping. However, five times zero is still zero, so all these helical LSD's work best when both wheels are 'planted' and some traction is still available on the slipping wheel. In practice this is rarely a problem as there is always some 'drag' on the slipping wheel, however some drivers expertly use left foot braking to partially lock the spinning wheel.
Note - Helical LSD's work especially well when combined with modern anti-lock braking systems.