With a name like Yellow Shark you can pretty much imagine the fierce performance this particular R34 demo car offers. When we heard from Sawa-san, the man behind Auto Select, that his GT-R development car had just gotten a hell of a lot faster thanks to a recently rebuilt engine, we couldn’t pass up the opportunity to drop by his shop in Osaka to take a closer look at what is one of the most extreme R34s in Japan. Sawa-san has been in this game since the early ’80s. He started off by tuning his friend’s cars and quickly became a master with setting up carburetors. When he opened up Auto Select with his brother in the mid ’80s he was known as the go-to man for the local hashiriya (street racers). Today, Auto Select is one of the most respected shops out there, having tuned pretty much every Japanese sports car ever made. But it’s the GT-R that has won them countless accolades, and they have just stepped their game up with this updated version of their original R34 GT-R R&D machine.
Sawa-san is a very knowledgeable guy; he understands cars inside out and has very strong beliefs when it comes to improving their performance. In his own words, “Power is nothing without control.” He always suggests his customers first improve their braking and suspension before even beginning to extract more horses. This is especially true when shooting for the best possible times out on track, where each area of the car is asked to deliver its best. The R34 perfectly represents this school of thought, with every component taken to the absolute limit, in particular the engine. The 2.7L stroked RB26 that was under the hood until last year has been ditched in favor of a very special and unique OS Giken RB3.15, the recently updated version of OS’ famous RB30 kit. Based around a stronger N1 Taikyu block the capacity has now been increased to 3,138 cc thanks to the use of a slightly longer stroke and fully counterbalanced crankshaft, stronger connecting rods, and 86.5mm forged pistons. To contain the increased stroke, now up to 89 mm, the block is extended by a precisely machined 26mm spacer (increased 3 mm from the older RB30 kit) and bolted down in place with special head bolts. Sawa-san jumped on the idea of this new engine as he is always in search of increasing lower-rpm torque to match the powerful top end. But he didn’t stop there, after porting and polishing the head and going for larger-diameter intake valves he fitted an HKS V-Cam Pro variable cam timing system to the intake side of the engine. This maximizes torque response and smooths out the delivery, allowing the driver to make better use of the performance when out on track. A massive Trust T88-33D turbine, delivering 850 hp and 650 lb-ft of torque, churns out close to the 8,500 rpm. An N1 water pump and Tomei oil pump keep vital fluids circulating through the engine, while cooling is handled by the ARC radiator and the twin Trust oil coolers. Keeping the engine’s thirst for high-octane juice quenched are the six Sard 1,000cc/min injectors, which are fed by two Bosch fuel pumps. Sawa-san has preferred not to upgrade the gearbox and still employs the stock six-speed Getrag transmission mated to an Exedy triple-plate carbon clutch and a shorter 4.1 final drive. The rest of the driveline has been beefed up with an OS Giken Super Lock LSD at the rear and an ATS carbon one up front. Engine management is handled by the HKS F-Con V Pro, which is joined by a host of other gadgets like the V-Cam controller and EVC boost controller.