"Kids have it easy these days," is a statement that reverberates among old school tuners. The pioneers of import tuning were forced to innovate custom turbo kits and dealt with the wiring challenges of installing an universal aftermarket ECU. Today complete forced induction kits and plug-and-play engine management systems are the norm. DSPORT Publisher Michael Ferrara and Associate Publisher Wen Lai have both tuned variants of Nissan’s legendary Skyline GT-R during the turn of the century. Their love of power and acceleration prompted heavy investment into their respective GT-Rs. Ferrara’s 9.86-seconds at 145 MPH and Lai’s 10.6-seconds at 139 MPH passes both required significant modifications to the platforms to reach their respective levels of achievement. The muscle car crowd looked on in shock and awe as these 2.8-liter, turbocharged six-cylinder engines rocked the track and raised the bar for import streetcar performance.
A DECADE OF DIFFERENCE
Fast forward to 2012, and now Ferrara and Lai can be heard echoing this sentiment along with many attendees at tracks across the nation. When Nissan’s flagship GT-R arrived in 2009, this technological tour de force raised the performance standard once again. Currently, the quickest and fastest R35s have locked down 8-second passes while maintaining a great amount of streetability. However, at one point its advanced engine management system, cramped engine bay, over 3,800 lb. curb weight and lack of a clutch pedal and traditional gearbox caused concern among many enthusiasts. When introduced, the R35 GT-R seemed like a “tuner-unfriendly” package. But, the aftermarket quickly embraced the platform and soon after solutions for improving performance were discovered.
GEARBOX GURU TO THE RESCUE
The race to build the quickest and fastest R35 GT-R was underway. In the beginning, the title switched hands between the top tuners in America every few months. As solutions for increased power were uncovered, the limitations of the driveline were exposed. Strengthening the GT-R’s GR6 twin-clutch transaxle became a necessity past the 700-horsepower mark. One of the first specialists to respond to this need was John Shepherd of Shepherd Transmissions, Inc. A long-time fan of AWD performance, Shepherd embraced the GR6 and studied the factory’s improvements year-to-year. “Many early problems were blown out of proportion,” Shepherd admits. “The most common problem is the weak first gear. Other common issues include circlip failures, piston seals, damaged selector pistons and synchro sleeve failures. Today, we have solutions for all of these issues.”
GT-R GUINEA PIG
Initially, testing the capacity of the GR6 transmission proved a logistical nightmare. Shepherd would ship the $20,000 transmissions across the country to different GT-R tuners to test his improvements to the GR6 and to collect feedback for future improvements. The time and expense invested into this method of testing quickly became impractical. This prompted the acquisition of a 2011 GT-R for product development. However, to find the thresholds of transmission performance, the VR38DETT engine would need to put down more power.
With only 180 miles on the odometer, Shepherd wasted little time getting the V6 engine into the Shepherd Transmissions workshop. Its cylinder heads took a trip to Head Games to receive port work and a complete Ferrea valvetrain. When the finished heads returned, ARP head studs secured them to a newly fortified VR38 block. The engine now features a balanced crank, courtesy of Canton Automotive Machine, Carrillo connecting rods and AMS-spec JE Pistons. AMS-spec Kelford camshafts actuate the valvetrain providing improved lift and duration.