SUPPORTING CAST
Big power and torque figures wreak havoc on factory GR6 transmissions. Sheptrans treated this GT-R’s GR6 to its Stage-4 package. The Sheptrans Stage- 4 package features the latest and greatest upgrades from PPG and Dodson to allow the GT-R to handle triple the original power output. A set of The Driveshaft Shop’s rear axles stay twist-free under the stress of 1,500 horsepower on one end and a set of sticky Mickey Thompson 345/35R18 drag radials on the other end. To provide a bit of weight reduction, Shep employed a Titan Motorsports lithium battery kit and removed the passenger seat for the record-setting pass. A GTC 102mm titanium exhaust was also fitted to reduce weight and provide a minimal-restriction, high-flow exhaust path. The GTC exhaust was so unexpectedly quiet and drone free that Shep went as far as using a bore scope to confirm that the muffler was a straight-through design.
RUNNING 8.40s?
While Shep doesn’t expect the record to hold for long, there is reason to believe that sub-8.50-second passes might be a future reality. According to Shep, “My 60-130MPH time was 3.30 seconds on the 8.61-second pass. This wasn’t ideal as I hit the 8,400 RPM rev limiter on the 2-3 shift. On an earlier 8.66-second pass, the car ran a 3.17-second 60-130 MPH time. There no reason to believe that some of that 0.13-second advantage might be realized on a better run. In addition, the density altitude was 2,600-feet on the record pass. An ultra-clean pass at better conditions might mean an 8.49 or better is possible.
THE BOTTOM LINE
“I expected bigger turbos and higher peak power would require a significant compromise in boost response. With the 4.1-liter engine and Alpha 12 turbos, I have not once wished that the combination “spooled” any quicker. If anything, the power application is a little bit smoother as it doesn’t blow the tires off as quickly,” says Shep. While many “planned” record-setting builds encounter a myriad of issues without ever reaching the end goal, it’s always nice to hear about a performance combination that surprises everyone involved.
