FOUNDATION FOR POWER

Given the short timeline, it was fortunate that GReddy had already invested several years developing an engine program for the VR38DETT. This helped to save precious time on the build. The GReddy stroker kit maintains the factory bore dimension since the plasma-lined cylinders have proven durable well beyond 1,000 horsepower. GReddy spec 8.6:1 compression CP Pistons fill the cylinders while Carrillo connecting rods make the connection to the GReddy stroker crankshaft. Up top, the cylinder heads received a port polishing service by Tom Fujita at Port Flow Design. Fujita also upgraded the valvetrain with Supertech valve springs and titanium retainers, with TOMEI Powered 272-degree camshafts providing lift to the factory valves. Once the heads were reunited with the block, ARP head studs provided the clamping force to hold the longblock together while GReddy MLS head gaskets ensured a proper seal.

PROTOTYPE FOR PERFORMANCE

Prototyping the new turbo kit would prove a little more time consuming. Aiming for over 1,000 horsepower, they decided to base the kit on a pair of billet wheeled Garrett GTX3076R turbochargers. Aaron, one of GReddy’s fabricators, invested 120 hours into the design of the kit, which was dubbed the GReddy GTX-R kit. Even Kenji invested 70 hours of his personal time after hours to help with the development of the kit. After lifting and dropping the chassis onto the engine several times over, the prototype turbo manifolds, 76mm downpipes and Supreme Ti 94mm Y-back exhaust system were finalized and completed. Aluminum piping makes the connection between the compressor outlets and the GReddy Spec-R HG Type 29 intercooler. Hard pipe from the intercooler feeds the GReddy RX intake manifold and RX 68mm billet throttle bodies, which then distribute the chilled air charge from the intercooler to the intake ports. A six-pack of Injector Dynamics 1,200cc/min injectors spray 104 octane unleaded race fuel into the cylinders. To regulate the flow of fuel and the spark timing, a COBB Tuning AccessPort was plugged into the OBDII port as GReddy refined the tables. Although final tuning has yet to be completed, at a peak boost of 20 psi, the GT-R is projected to put down 1,150 horsepower and 1050 lb-ft torque to the rollers of GReddy’s Dynojet AWD dynamometer.