One issue with the RB26DETT engine is proper oiling, and Johnson found out about this the hard way with a case of rod knock. As the car sat at XS Engineering with the engine pulled out, Johnson sat down to have the hard talk with Hsu. Since the engine was pulled anyway, they decided to go all-out, while ensuring the car could pull off more power and last longer at the same time. With his dollars disappearing into thin air, Johnson assembled himself possibly one of the greatest street cars of all time.
The motor was rebuilt with factory pistons and rods, but the block is a balanced and blueprinted N1-spec unit sourced from Nissan, machined by Cosworth and built by XS Engineering. An HKS metal head gasket is sandwiched between that dream-team bottom end and a completely reworked cylinder head. A'PEX valve springs, Nissan N1 racing valves, Mine's baffle plates, and Tomei valve lifters and adjustable cam sprockets provide backup for the truly inspirational head modifications. Custom ported by XS Engineering and fitted with custom spec'd HKS billet camshafts with high lift and high duration, the cylinder head boasts some truly top secret in-house tricks from XS Engineering.
Responding to the past oil delivery issues, Johnson fitted his Skyline with a custom Tomei oil pan with some trick baffles; short of a dry sump system, this is the cleanest way for Skylines to hold their oiling during high-g maneuvers. Pumping through a Reimax Group A racing oil pump, Motul racing oil--expensive, but well worth it--bathes all the ins and outs of the RB26.
What's the power feel like? With a pair of GT2530 turbochargers blowing into an XS Engineering intercooler and A'PEX hard pipes, the GT-R produces 545-wheel hp on 91 octane and 625-wheel hp on 100 octane. HKS tubular stainless exhaust manifolds and Quest custom downpipe extension elbows provide smooth exhaust flow, and Jecs Racing mass airflow sensors provide extra metering for the extra amounts of oxygen being inhaled. Full boost of 1.8bar (about 26.5 psi) builds at 4200 rpm and holds all the way until 8400 rpm, with 480 lb-ft of torque available as measured on XS Engineering's four-wheel-drive dyno. Part for part, Johnson fully believes his car capable of destroying Nismo's much-vaunted limited-edition Z-Tune GT-R. And you know what? The Power FC maps tuned by XS Engineering allow the Skyline to drive unbelievably well considering the amount of modifications and power that it is now producing. Godzilla indeed.
The stock transmission was left alone, but the clutch unit is a Nismo G-Max twin-plate and flywheel, with a Nismo slave cylinder added in. The slave cylinder transforms the feel of the twin-plate, providing stock pedal feel and pressure. For time attack duty, the driveline received a Nismo front limited-slip differential and Kaaz two-way rear LSD, with the center differential unit left bone stock. The car's suspension was completely rebuilt. Every single control arm, link, sway bar or tension rod has been replaced with a Nismo, Cusco or Nagisa Auto part. Completely adjustable in every possible manner, the GT-R's suspension helped it lap one-third of a second off of the fearsome Signal Auto R34 Skyline at the GT Live time attack battle.