Blackline HLF024 BMW 188K Medium Case Helical Gear LSD

The Blackline HLF024 helical limited-slip differential is designed for BMW models fitted with the 188mm 188K medium 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 188mm medium case diffs, used in the vehicles listed below.

Medium case 188mm (29.5mm offset) 10 bolt crown wheel differential

• 1 Series E81 118d manual
• 1 Series E82 120d manual
• 1 Series E87 116d manual; 120d auto up to 01/2007; 120d manual
• 3 Series E46 320d auto; 320d manual (2.79:1 ratio); 323i manual; 328i; 330i manual; 330xd
• 3 Series E90 318d; 320d manual (7566218 & 7566274 diff); 325d; 330d; 325i manual (7566172 diff); 330dx auto
• 3 Series E92 320d; 325d; 330d; 325i manual (7519942 diff); 330dx auto
• 5 Series E39 520d manual; 525d auto; 525i manual; 528i manual; 530i manual; 535i; Alpina B10 3.2 manual (2.93:1 ratio); Alpina B10 3.3 manual
• 5 Series E60 520d manual; 525d auto after 03/2007; 530i manual
• X3 E83 3.0d manual rear axle
• X3 F25 SDrive 2.0d rear axle
• X5 E53 3.0d manual rear axle
• Z4 E85 2.2i manual; 3.0i manual; 3.0i SMG

• 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