Dai Yoshihara’s Two Week Wonder, GT Channel’s Time Attack 350Z


OS Giken 350Z LSD diff
The OS Giken Limited Slip Diff offers a lot of adjustability–good for chassis setup.  It also runs cooler than most other differentials–important in the 350Z where the diff has very poor airflow and runs dangerously hot without a cooler.

An OS Giken 1.5 way limited slip differential was used, replacing the stock viscous LSD. The OS Giken is known for its superior power delivering properties, great adjustabilty and low temperature operation.  This was highly important as there was no time to install a diff cooler in the 350Z which is notorious for running high diff temperatures. A finned Nissan Motorsports diff cover was installed for better cooling and additional oil capacity.  SPL Pro solid aluminum diff bushings also were installed to eliminate flex and help reduce any chance of wheel hop.

SPL 350Z diff bushings
The blue anodized parts are SPL’s Pro Series solid differential mount bushings.  These help eliminate wheel hop.

Dai’s crew consisting of industry experts like Costa, Chris Marion, John McNulty and Yours Truly labored right up to when the car was loaded on the trailer to Buttonwillow.  At the Superlap Battle, the car was not expected to do well or win, as the event was treated more as a shakedown. To everyone’s surprise the car ran well for two straight days. Track time was spent getting the chassis settings down and figuring out what the car would need to be competitive later.

Nissan Motorsports 350z diff cover
Nissan Motorsports diff cover has a larger sump capacity and fins for better cooling.

The car fought fuel starvation in corners and brake problems with cracking front rotors taking the car out of action on both days. The car was definitely way too heavy and lacking power to run with the fastest cars. The Z was the slowest car on the straights but it more than held its own in the corners even with the engine burbling from fuel starvation causing the car to kick sideways. Sometimes it helps to have a pro drifter at the wheel!

Dai will be back in 2010. The car will have plenty of time for more development with better brakes, more power, weight reduction, aerodynamic downforce and diff tuning on the books. MotoIQ will be there to cover the cars build as it is developed and to assist as needed.

Look out for Dai in the coming season!


GTI Motosports

GT Channel


Falken Tire

Volk Wheels

KW Suspension

SPL Parts

Jim Wolf Technology




Performance Friction

OS Giken

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