[Mike@VAC]

VAC is proud to be a master stocking OS Giken dealer.

BUY NOW AT VACMOTORSPORTS.COM

OS Giken = the choice of enthusiasts and racers who want "the best" clutch type LSD available. Example: Berk Technology runs OS Giken in their famous 135i.

Up until recently, very few enthusiasts in BMW land knew the name OS Giken [pronounced (oh. ess. gee-ken)]. However they are a legendary Japanese tuner and manufacturer of super high end race parts. Sensing the BMW market was in dire need of performance differentials, OSG developed their unique LSD technology for the BMW market.

OS Giken is rapidly becoming the choice of the Porsche enthusiasts where rear engine layouts and high horsepower require perfect control and stability. The BMW racer and enthusiast can also immediately appreciate the excellence of design and performance the OS Giken offers to their vehicle from the moment they drive.

The OS Giken Super Lock LSDs are much like other clutch type LSDs in that they offer the quick, positive response that some drivers prefer vs. a gear based / torque biasing differential. Some standout features the OS Giken has involve it doing it's job better than any of its clutch type competitors:

-Extreme performance; capable of 100% locking on demand
-20 Clutchplates! Many clutch-style units only have between 4 and 8 total!
-Incredibly smooth response; suitable for comfortable daily street use
-Durable: extremely long life for both street or track use- tested to maintain performance over a vehicles entire lifespan
-Strong: nearly unbreakable - used as delivered by professional drifters and championship racers
-Precision machining; long life and ready to use out of the box, no break in required

Superior Design
-Miniaturized pressure ring and a superior spline-through-side-gear design allows for fitment of more friction plates (up to 2x as many as competitors versions), offering true 100% lock capability.
-Patented pressure ring design allows for smooth, progressive locking
-Case has a relief cut-out for the cone spring, for minimized cone-spring flexing and enhanced durability.

Superior Construction
-All components are chemically heat treated for maximum durability
-All components are constructed with high-grade steel alloy
-Gears are raw-forged for maximum strength
-Disks are precision-machined simultaneously on both sides to extremely tight tolerances
-Case is billet construction

Tunability
-Initial torque can be adjusted by using thicker / thinner cone springs
-Lock progression timing can be adjusted by using stiffer / weaker pressure ring springs
-Ramp angles can be customized by swapping the pressure ring and iron cross
-Disks can be swapped to TCD type for enhanced oil flow properties

Superior Overall Performance
-The OS LSD standard spec allows for low preload while still retaining a fully progressive 100% lock capability; basically, the vehicle will feel like driving on an open diff in slow turns / street driving, but can still transmit maximum power to the drive wheels under load.
-Operation is ultra quiet, and the progressive locking allows for smooth, predictable locking. Especially when replacing an open diff, equipping OS LSD will completely improve the driving experience while maintaining everyday drivability. With OS LSD equipped, inside wheel spin can essentially be eliminated, and throttle steering becomes unequivocal.
-Due to the precision manufacturing, high-grade materials / processes used, and superior design, no break-in period is required for OS LSD, and no rebuilds are required. OS LSD is purposefully over-engineered to offer the best performing, most durable clutch-type LSD available.
-Aside from the performance advantage and stock-like feel at slow speeds, vehicles equipped with OS LSD are more stable in all road/weather conditions, allowing for a safer driving experience.

[Mike@VAC]

Reserved.

[Mike@VAC]

This review just came over our site.

I'm very pleased with this LSD & VAC's no-nonsense professionalism. I highly recommend that this unit be installed into a differential housing by VAC Motorsports as there are multiple specs and clearances such as ring and pinion contact patch, backlash, end play, etc, etc., which must be set up using precise tolerances. Most shops aren't going be equipped with the necessary shim/snap rings to accommodate all installations due to manufacturing differences. Not to mention the machinery necessary during the processes of separating the ring gear and machining it to spec.

I opted for the OS Giken's Superlock rather than the TCD unit because I am hardly, if ever, a hot-rodder and will likely never track the car. Of the 1,200 miles I've driven while breaking the unit in, I can not perceive any differences between this LSD and the stock open differential during normal street and highway conditions! That is to say: to its credit, it's operation is; smooth (no inner tire chirping or snarling one wheel rear end kick-outs while initiating turns); silent (no startling bangs/clangs or embarrassing crackling/popping noises while accelerating, decelerating, coasting or backing up; and imperceptible/unobtrusive during non-aggressive driving conditions because of the unit's positive disengagement thanks to its counter-sprung inner locking mechanism. During turns at higher speeds, I can feel the rear end "hunkering down" progressively and predictably as the load is increased.

Gone is that "wishy-washy teetering bouncy floaty feel" at the rear end. I was also pleasantly surprised when my car felt like it was riding on rails rather than "bouncily pushing out" when I found myself going around a corner way too fast while having to decelerate (oops)............for those of you who know proper car lingo, I apologize for lacking the "correct vocabulary" to explain the preceding "descriptions." As of now, I have yet to experience any conflicts between this LSD and the factory's eLSD (electronically-simulated LSD) and/or the ABS (Anti-lock Braking System). For those of you contemplating this upgrade, I can without any reservation recommend this unit and VAC Motorsports.

[Mike@VAC]

3.08 gas, 2.56 DCT and 2.81 diesel FINAL DRIVES with Quaife ATBs and OS Giken Super Locks built and IN STOCK. :-)