Forged Performance/ OS Giken LSD Review (pics)

Sharif@Forged

Just to clarify with respect to the installation issues. We're very familiar with Nissan's habit of using different length and shaped stub axles in the various trims of 350Z. With the 370Z, the base model includes traction control but still an open differential. In the process they also elected to use a revised set of stub axles as well. So with 6 different stub axle choices even OS Giken wasn't entirely sure what ones to use. We ordered one short and one long axle in preparation for the installation. Upon inspection of the OEM parts we discovered that we need two SHORT stub axles NON TAPER with snap ring grooves/snap rings. Instead of sending Chris home and ordering a second short stub axle we machined and modified his existing axle to precisely the same measurements and tolerances of the OEM part which including machining a new snap ring groove. This is a substantial amount of extra time, but we didn't charge the customer of any of this and our objective was to complete the job as promised and get him on the road safely. Under normal circumstances no modifications are needed during install. Mission accomplished.

Shifting gears to the performance aspects, the OS Giken is the highest performing and smoothest engaging clutch-style LSD we've used in every car we've put them in. Prior to using them on the 350Z/370Z, we had used them on the GT-R, Subaru, and Porsche GT3. It's the best kept secret in performance handling and laptime reduction, bar none.

The OS Giken is a 1.5 way clutch style LSD, with a perfectly machined outer case and ring gear shelf. No shims have ever been needed in our installs and that says a lot about their machining processes. The LSD locks 100% under acceleration, and 50% under deceleration and has an undetectable ramp that is seamless in it's engagement.

The best way to test and describe an LSD's action is on track, but the benefits as Chris alluded to are also immediately apparent during street use as well. A full locking differential allows the driver to roll into full throttle much sooner in the corner, without causing speed robbing wheel spin. On the OEM diff this is very noticeable on tight and slow mountain roads such as those that have visited the Tail of the Dragon. In contrast, with a "locked" arrangement you are providing equal thrust to both engines back there (your tires). Although it seems contradictory, you do not want an overload of power to the tire that is gripping, as it quickly causes you to light up BOTH tires and you cannot control the back of the car with the throttle as readily as a locking diff.

Hope that adds some additional color, to an already awesome product. Now lets talk about the OSG Twin Plate Clutches....haha...ok next time. Thanks for reading.

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Sharif@Forgedperformance.com
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