Chassis-wise this GT-R has been prepared from the ground up just like a race car. After being fully stripped and cleaned it was spot and seam welded and reinforced in various high-stress areas like suspension mounts. A full rollcage was welded-in and additionally braced to the chassis, as can be seen around the A-pillars and on top of the windshield. Matsumoto-san explains that a lot of work went on inside the wheel arches as this car runs a full custom double wishbone layout at the front and rear. Unfortunately, we weren't able to get further details on this since a lot of engineering went into a conversion like this and they can't afford to get their ideas copied.
The Quantum dampers, running Hyperco springs, are mounted vertically instead of a more complex push-rod style layout like the GT Skyline GT-Rs used to run. Braking is down to a full Brembo Racing system made up of eight-pot front calipers and four-pot rear calipers. These share nothing with street-spec kits as the actual calipers are made from lighter alloy and have magnesium pistons. On top of this they can easily be taken apart for servicing. These are mated to huge 380mm front rotors and 324mm rear items, both using a floating type center bell mount. Hi-friction Endless pads are used and the system is pressurized by a custom master cylinder. With only 1,180 kg of mass, these brakes haul the car down from any speed in a split second!
Matsumoto-san got a lot of inspiration from the RBs that were used in JGTC. He focused on trying to develop a strong mid-range as well as a powerful top end. During our coverage of the Tsukuba Lap Battle event last year we were astonished at how fast this car shot out of the corners with instant acceleration. The engine is built around the Nismo GT block, the same "RRR" labeled block used in the GT cars. It's already bored to accept a 2.8L bottom end. M-Speed used Tomei components, which are known for their flawless quality. The full counterweight and balanced crankshaft join the H-section connecting rods and the forged pistons
Everything was balanced to very fine tolerances before being fitted. A lot of secrecy surrounds this engine but we were told that the compression has been lifted to 9.2:1, probably with a combination of piston and metal head gasket selection. Tomei also supplied the oil and water pumps. The head was processed to promote better breathing and fitted with full Tomei valve gear. Joining this RB28 is a pair of specially modified IHI built A'PEXi AX53B60 turbines bolted on M-Speed exhaust manifolds. It is thanks to these that a monster 92 kgm of torque can be developed. With no need for a street-legal exhaust, hot gasses are dumped out the side of the car via a custom titanium system. Custom pipe-work feeds the turbochargers with air from the custom airbox and then on to the ARC intercooler. A Nismo inlet plenum is used to ensure each cylinder receives the same amount of air.
Fuelling is taken care of by two Bosch fuel pumps that fish the fuel from the racing fuel tank in the trunk and send it via the Sard fuel rail to the 1,000cc/min injectors. A Sard fuel pressure regulator keeps things in check, while the Okada Project ignition coils make sure every last bit of fuel is efficiently ignited. Cooling the water is a large-core Calsonic radiator, while the oil is kept in check by an ARC oil cooler. Nice detailing like the carbon cam cover and the GT-like titanium turbine heat shields help make this GT-R even more unique. The driveline has been uprated with an ATS triple-plate carbon clutch and a Hollinger six-speed sequential gearbox with ratios especially selected to make perfect use of the power and torque bands at Tsukuba. Helping the car develop even more mechanical grip is the ATS front carbon LSD while the carbon propeller shaft keeps rotational mass low and increases engine response.
Just like the rest of the car the interior is pure racer. Open the carbon doors, which also have carbon inner shells, and you have a perfect example of minimalism. Everything that isn't needed is simply not there. The factory dashboard has been replaced with a dry-carbon copy, while the center console was binned in favor of a custom one neatly housing all of the switchgear. The only instrumentation is the Motec data logger/dash unit cleanly fitted in front of the Racetech steering wheel. The driver, in this case Tetsuya Tanaka of Super GT fame, sits in the carbon-Kevlar Recaro seat and is safely strapped down with Takata belts. The Hollinger sequential shift lever is at easy reach for lightning-fast gear changes. Finally, the engine management is down to the extremely powerful Motec M800 ECU, which had to be custom wired into the car.
The 2007 Rev Speed Tsukuba Lap Battle is setting up to be an amazing event this year. With the big boys like this M-Speed GT-R, the Garage Ito GT-R and the Unlimited Works Cyber EVO shooting for sub 54-second laps, this will no doubt be the event of the year. You can bet we'll be there with our cameras ready to bring you all the action!