A typical tourist visiting Japan looks forward to eating sushi and visiting famous landmarks. The editors of Turbo, however, look forward to traveling throughout the island in sub-compact cars in a never-ending quest to find exotic imports unavailable in the U.S. market.
Turbo magazine met Kazuhiko Nagata, president of Top Secret Japan at the 2003 TAS (Tokyo Auto Salon), and soon after visited his shop. With cameras in hand and U.S. Benjamins converted to Yen-jamins, we motored our way to Chiba prefecture to see Top Secret's latest creations. The first of these masterpieces was the twin-turbo 350Z we featured in August 2003. The monster featured in this issue is the Top Secret Skyline GT-R.
The R32 Skyline GT-R was engineered as a racecar, destined for Japan's Group A class. In 1990, it was unleashed in competition and eventually dominated the series, a feat that had never been witnessed in Group A competition. The following year sanctioning groups mandated a weight increase on the GT-R to give its competitors a fighting chance, but the GT-R again blew away the field, winning all 29 races in Group A. Finally, the car was banned from Group A racing in 1992 and campaigned in a class exclusively for GT-Rs.
The Skyline GT-R remained the top dog of Japanese supercars for years to come. The R32 gave way to the R33 and R34 models, with each new generation getting softer body lines, but all retaining the RB26DETT engine and ATTESA all-wheel-drive system. Factory rated at 276 hp for insurance reasons, tuners were able to easily uncork incredible power and performance from the GT-R. To see this potential realized is what brought us to Top Secret and its wicked R34.
Top Secret started the transformation by removing the factory RB26DETT head giving it a special Top Secret massage, complete with Trust SP valves and HKS high-profile cams 280 IN/280 EX. Like the company name, the compression ratio is under wraps no matter how much we tried to con them into telling us. The bottom end has been fortified with HKS Step II pistons and Trust H-beam connecting rods. Air is chilled through a Trust three-layer intercooler before being force fed into a TS 50mm intake manifold conjoined to a Infiniti throttle body.
Boost characteristics were systematically altered with the removal of the twin-turbo setup in favor of a single-turbo attack. A Trust T78-33D turbine mated to TS's 50mm exhaust manifold efficiently brings power levels to a respectable 738.5 PS (728.38 hp) and 67.5 kgm (488.03 lbs-ft.) of torque. On the hot side of the turbo, spent gases are expelled through a TS downpipe and TS Titanium Pro exhaust system.
An HKS FCON-V Pro commands fuel and spark parameters for the Skyline, guaranteeing reliability, which is one of the RB26's strong suits. Ensuring all the horsepower is efficiently transferred to the tarmac is a difficult feat. With that in mind, Top Secret combined an ORC twin-plate clutch system and Cusco LSD differential to handle the rigorous circuit-racing demands. Top Secret installed its oil cooler and an ARC Prestege-R aluminum radiator to keep the 2.6-liter engine at low temps for casual city driving or full competition on the track.
Engine vitals are carefully monitored with the aid of a Yashiyo Factory digital water temp meter, Neko AF700 air fuel gauge, Blitz FATT DCC meter, and a trick carbon-fiber gauge cluster. Safety features include Recaro SPG buckets along with a set of Takata MPH340R harnesses to keep the driver firmly fastened when hitting the turns. A 10-point roll cage was shoehorned into the car, while a complete body spot weld was implemented, adding rigidity to the chassis.
Limited-edition wheels made exclusively for Top Secret were the weapon of choice for the Fusion R34. Wrapped in a set of 265/35-18 Bridgestone 540s in conjunction with Top Secret super dampers on all four corners, the Fusion R34 has made its mark on the circuit at Tsukuba raceway with a best time of 57.914 seconds. Braking demands are handled with a set of Brembo eight-pot calipers in the front and four-pot in the rear.