Blackline BMW E46, E81, E82, E87, E90 (168L Diff) Helical LSD

Blackline BMW E46, E81, E82, E87, E90 Helical LSD for vehicles fitted with 168L differential.

Suits:-

E46 316i
E46 316ti
E46 318ci Manual
E46 318i Manual
E46 318ti Manual
E46 320i Auto
E46 320i Manual with 168K casing
E81 118i Manual
E82 120i Auto
E87 116i Manual
E87 118d Manual with 168L final drive
E87 120d Manual with 168L final drive
E87 120i Auto with 168L final drive
E87 120i Manual with 168L final drive
E90 320i Auto with 168L casing
E90 320i Manual with 168L casing
E90 320si Manual with 168L casing

BMW chose after the mid 90s outside of the ‘M’ cars to not fit an LSD, instead limiting the power by traction control, thus limiting the performance potential.

The ATB combined with BMW’s superb chassis and handling qualities allows the power to be efficiently handled, making the car faster, especially in slippery conditions.

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
Blackline Helical LSD’s – How They Work
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.