Blackline HLF020 BMW 168L Small Case Helical Gear LSD

The Blackline HLF020 helical limited-slip differential is designed for BMW models fitted with the 168mm 168L small case differential, providing a direct performance upgrade over the standard open differential. By intelligently distributing torque between the driven wheels, it improves traction, cornering stability and power delivery, making it ideal for fast road and track use.

Unlike clutch-type differentials, this LSD uses a precision helical gear torque-biasing design, eliminating clutch plates and the associated wear. This results in smooth, progressive engagement with minimal noise and virtually no maintenance requirements.

It is a torque-biasing differential that automatically transfers torque to the wheel with the most available grip. This significantly improves traction during acceleration, particularly when exiting corners or driving in low-grip conditions.

Inside the differential, parallel-axis helical gears generate internal thrust forces proportional to the applied torque. These forces create resistance within the differential housing, allowing torque to be directed to the wheel with greater traction while maintaining smooth operation during normal driving.

With a 5:1 torque bias ratio, the Blackline LSD can transfer up to five times more torque to the wheel with the most grip. This allows the differential to handle significant traction imbalances while maintaining predictable and stable handling. In rare situations where one wheel has completely lost traction, techniques such as light braking can help the differential redistribute torque effectively.

Manufactured from high-strength 8620 alloy steel, it is built for durability and long service life. Precision machining and heat treatment ensure it can withstand high torque loads in demanding performance environments.

Compared to a standard open differential, the Blackline LSD provides several key advantages:

• Improved traction under acceleration
• Reduced inside wheel spin when cornering
• Smoother and faster response than viscous LSD systems
• Progressive engagement without harsh locking
• No clutch plates to wear or require servicing
• Quiet operation suitable for road and track use

The differential is designed as a direct replacement for the original unit, fitting the 168mm small case diffs, used in the vehicles listed below.

Small case 168mm (39.4mm offset) 8 bolt crown wheel differential

• 1 Series E81 118i manual
• 1 Series E82 120i auto
• 1 Series E87 116i; 118d; 120d manual
• 1 Series E87 120i auto & manual
• 3 Series E46 316i; 316ti
• 3 Series E46 318i; 318ti; 318ci manual
• 3 Series E46 320i auto & manual
• 3 Series E90 320i auto & manual
• 3 Series E90 320si manual

• See images for dimensions
• The LSD is a straight swap for the standard unit, you will only need to replace gaskets/seals and 2 diff bearings (if the originals cannot be re-used)
• Helical gear diffs do not require a special oil (OE diff oil is suitable)
• This is a torque-biasing helical gear limited slip differential - not a plate type, viscous coupling or clutch pack differential (it does not lock)

• Includes assembled differential unit only
• Bearings, gears, gaskets/seals etc are not included