To those familiar with the Japanese tuning scene, the name Top Secret is synonymous with speed and creativity. The company was founded by Kazuhiko “Smoky” Nagata, a man who got his start working for the turbo-tuning experts at GReddy/Trust. The name Top Secret comes from the hidden projects he did on the side in the Trust engineering department unbeknownst to his colleagues. Once they found out, he resigned and founded his own tuning venture to let his ideas take on a life of their own. Ideas, such as putting a twin-turbo V12 into a Toyota Supra and shipping it to Nardo, Italy in search of a 400km/h speed record (248mph). Nagata’s secrets are out, and since the release of the new Nissan R35 GT-R in late 2007 he has set his sights on perfecting the latest version of Godzilla. The gold-painted demo car you see here is the culmination of his tuning efforts over the past four years.
The R35 GT-R is no slouch to begin with. Off the showroom floor it came with a 3.8-liter twin-turbo V6 engine that was factory rated in Japan for 478 hp and 434 lb-ft of torque. The power is sent through a semi-automatic dual-clutch transmission, located in the rear for better weight balance, to Nissan’s ATTESA E-TS all-wheel drive system. The GT-R’s relatively low price (starting under $100k) and Porsche-defying performance has earned it praise for being one of the best bang for the buck supercars ever made.
Still, Nagata saw plenty of room for improvement. As with any turbocharged car, the first place to start was the exhaust. 1,000 years ago, Japanese sword smiths were renowned for the steel they used in katanas. Now, when it comes to automotive tuning, no one does titanium better. Top Secret uses the lightweight material for their TV-Pro Version 2 cat-back exhaust piping. The muffler also features a unique bypass valve with a silent mode that can be activated remotely to lower the volume by ~5db. Closer to the engine, what Nagata labels the #1 Extension Tube and #2 Sport Catalyzer were also fitted for better breathability. The numbers denote the street-legal versions of each piece. Top Secret also offers a #2 Extension Tube that completely deletes the catalytic converter for maximum exhaust flow on a race track.
Next came the intake side. The Top Secret Super Induction kit replaces the dual intake piping with stainless steel tubes and green HKS filters. A carbon fiber shroud sits over each filter element, shielding them from hot ambient air. The intercooler piping has also been upgraded, and GReddy blow-off valves regulate the excess gases.
The real genius behind the GT-R’s power lies in its upgraded turbochargers. Unlike a Supra or Evo’s engine, a regular stand-alone turbo cannot simply be bolted onto the R35. The stock IHI blowers are molded into the exhaust manifolds, and Top Secret’s High Flow BB units feature the same integrated design. They are also larger - the turbine wheel itself being about 22% wider in diameter versus stock. Although Top Secret offers a few different BB turbo kit options, this golden child showcases their BB900 setup. As you might guess, the number denotes the car’s output, which is a staggering 900 hp and 745 lb-ft to the wheels!
Getting the most out of a turbocharged powertrain can require many hours, or even weeks of engine mapping. Modern automobiles don’t always enjoy being messed with, and the GT-R is no exception. Nissan fitted it with an ECU that is more like the CIA mainframe at Langley: no hacking allowed unless you are Tom Cruise suspended from the ceiling. Nagata took on the Mission:Impossible challenge, creating his own PROcess R ECU to optimize all of the variables such as boost pressure and fuel delivery. Stock GT-Rs have almost no turbo lag, and the Top Secret car was fine tuned to be every bit as smooth with newfound grunt.
With all of that power at his command, Nagata needed to reinforce the engine’s internals to make sure his dyno run wouldn’t be a one-time affair. HKS pistons, connecting rods, and head gaskets, along with JUN camshafts make up the engine’s internals, while Moty’s fluids and a Trust DCT oil cooler keep things lubricated. For the transmission, a heavy duty clutch and first gear set from Dodson Motorsport ensure that launch control can be used worry free.
Top Secret’s tuning expertise doesn’t end with the engine. The carbon fiber G-Effect body kit on their gold R35 was also developed in house, consisting of a new front bumper, hood, side skirts, trunk lid, rear wing, and rear under diffuser. Look closer, and you will be seduced by the detailed craftsmanship given to each panel. The front lip for instance extends 5cm farther than the stock bumper for added downforce, and has two air inlet ports. The rear wing is taller, and its angle can be adjusted by merely stepping on the brake pedal à la the Bugatti Veyron or McLaren MP4-12C. The hood has extra vents up front to release heat, and ducts on the underside that route air directly to the intakes. There are even titanium tow hooks that can be folded back into the bumper when not in use. Matched up with a set of 20-inch Rays VR.G2 wheels the car is nothing short of drool-worthy.
On the handling front, Top Secret offers their own brand of dampers called Aragosta. Available in one, two, or three-way flavor, the coilovers have Swift springs for increased response. Like the exhaust system, the suspension’s height can be controlled off-board with Nagata’s Roberuta cap kit. To improve braking, Top Secret 400mm front and rear rotors are paired together with Endless brake pads. The calipers are already as big as an adult’s head, so those were one of the few stock parts to get the thumbs up, for now.
Inside the GT-R, things have been kept like OutKast: so fresh and so clean. The stock front seats were ditched in favor of a set of Bride Zeta III’s, each paired with green Takata four-point harnesses. The interior trim is finished off with a set of unique Top Secret GT-R floor mats dyed orange-gold to match the body’s signature paint job. This demo car functions as a proving ground for the parts that Nagata sells to everyday GT-R owners as well as race teams. As such, it retains the factory audio system, navigation, and various driver controls to verify that none of the Top Secret add-ons have had an adverse effect elsewhere. The rearview mirror on the other hand was replaced with a more JDM-style accessory unit. It has an LCD screen to display the video feed from the fender-mounted side view cameras. Simple, but important when it is time to park in warehouse full of expensive customer cars.
The Nissan R35 GT-R was an improvement on the Nissan bloodline in every way. It was faster, handled better, looked meaner, and ate German supercars for breakfast. It seemed like the pinnacle of Japanese engineering, but as evidenced by Nagata, it was only the beginning of another legend. Top Secret has turned the volume up to 12 for a car that was already playing at 11, and we can’t wait to see what they come up with next.
Essentials // Owner: Kazuhiko “Smoky” Nagata • Location: Chiba, Japan • Vehicle: Nissan GT-R (R35) • Power: 900 hp
Intake // Top Secret Super Induction Kit exhaust // Top Secret TV-Pro V2 Titanium Muffler and Front Pipe Turbo // Top Secret BB900 Turbo Kit; Upgraded Intercooler Piping; GReddy Blow-Off Valves engine // HKS Pistons, Rods, Head Gasket; JUN Camshafts; Top Secret PROgress R ECU Tune
Transmission // Dodson Heavy Duty Clutch and First Gear Set; Kansai Service Rear LSD
Exterior // Top Secret G-Effect Carbon Fiber Body Kit; Carbon Hood, Trunk Lid, and Adjustable Rear Wing wheels And Tires // Rays VR.G2 Fr. 20x10”, Rr 20x11” / Dunlop SP Sport MAXX GT 600 DSST CTT Run-flat 285/35ZRF20 Suspension // Top Secret Aragosta 2-way Dampers with Roberuta Cap Kit brakes // Top Secret Rotor Kit; Endless Brake Pads interior // Bride Zeta III Seats; Takata 4-point Harness