OS Giken Superlock Technology

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OS Giken's patended Superlock design features many proprietary features which make these units technically superior to the standard limited design which dates back to the 1970s. Diff Lab is proud to share these design innovations with you, with these OS Giken technical diagrams translated to English.

Superlock Springs

LTCS: Lock Timing Control System

Small coil springs (usually 12 springs) are built into the pressure ring assembly. These springs apply negative pre-load to the pressure rings, and hold them in the "off" position. The spring pressure is overcome with engine torque, when engine torque is applied.

When only a small amount of engine torque is applied, it will not be enough to overcome the spring pressure to any noticable amount, and little to no locking will occur. This means that casual driving is smooth and with very limited clamping of the plates. Only when more torque is applied will the plates clamp substantially. (Patented: Japan, US, Taiwan, Korea)

Superlock Clutches

STSG: Spline Through Side Gear

The overall locking capability of a limited slip unit is determined by the clapming pressure and surface area. The Superlock STSG design features larger-than-normal friction surfaces, for a substantial increase in surface area. This increases longevity abd locking capacity, while reducing operating temperatures. OS Giken Superlocks often feature 1.5x to 2x the number of plates than your average limited slip unit. Because the design principle is one of lighter pressure and larger surface area, the locking is applied more smoothly and quietly. (Patented: Japan, US, Taiwan, Korea)

Superlock compressed

This diagram shows the compressed state of the Superlock. All of the negative pre-load coil springs are almost completely compressed, and the end springs at the extreme left and right are entirely compressed. When engine torque is removed, the coil springs will unload the plates completely, and allow the car to turn-in as sharply as possible. The Superlock turn-in is the best in the business.


Advantages of the OS Giken Superlock LSD

  1. Long Life: the Superlock design has been tested at 150,000km and showed little wear.
  2. Thermal Stability: during endurance races and continuous racing, there is almost no reduction in locking due to thermal sag.
  3. Smoothness: gentle operation and fast unloading means you barely hear or feel the LSD's operation.
  4. Custom Setup: most Superlocks can be ordered with numerous thrust rings and spring setups.
  5. Customizable : the end-user can make adjustments with spring pressures and clutch plate count without special knowledge or additional parts.
  6. Cornering: because the locking action is very light with light torque loads, cornering ability is not substantially affected by the locking action.
  7. Exit: on corner exit, the locking is applied smoothly all the way to complete locking (if setup to lock completely) so the vehicle does not become unsettled.
  8. Apex: on corner apex, when throttle is at its lowest, the Superlock will unload the plates almost completely and give you the best possible turn-in at apex.

Other info:

OS Giken Clutch Technology

OS Giken Product Page