If there’s one form of motorsport that’s brought out the best in the Japanese aftermarket performance tuning industry, it’s time attack. For more than a decade Japan’s most recognized tuners have been in on the act, building cars specifically for chasing down lap times. These days it’s a world of GT-style cars capable of physics defying lap times. The Scorch Racing S15 certainly fits the bill, but scratch a little deeper and you’ll discover that this isn’t a shop car designed for promotional purposes, but a privateer entry, owned, built and driven by a 36 year-old office worker from Tokyo. His name: Tomohiko ‘Under’ Suzuki.
When Suzuki-san first purchased the Silvia the intention wasn’t to create a full-blown race car, but rather a lightly tuned streeter that could hold its own during weekend jaunts at the track. Twelve years on, you don’t need to look far to see that this S15 is far removed from its days as daily commuter. But when you meet the man behind this project, it all makes sense. This car is Suzuki-san’s life. “Building my car is my favorite—and only—pastime,” he reveals. “I’m quite busy with my work and all the rest of the time I spend on the car. I’m always staying up very late at night and always tired. But then, when I go to the circuit to drive, I’m happy. Progress is made little by little every year, but this is my way of having fun. I’m passionate about what I do.”
But that passion hasn’t just led to creating one of the wildest looking time attack machines on the planet, but one with the absolute performance to back it up. Suzuki-san’s goals are clear: he wants to win at the World Time Attack Challenge and he wants be better the Tsukuba Circuit lap time Nobuteru Taniguchi set behind the wheel of HKS’s all-conquering CT230R Mitsubishi Lancer Evolution. The latter might sound like an improbable aspiration for guy who wrenches on his own car after hours at Scorch Racing’s workshop in Machida City, but right now he’s just half a second off realizing that dream.
One of the most impressive aspects of the build is the way the car looks. The aero package has been a work in progress for a few years, but most recently became the recipient of a dry carbon-fiber T&E Vertex roof, wide carbon rivet-on rear over-fenders, a carbon trunk lid with integrated lip spoiler and a rear diffuser. Initially, Suzuki-san began designing (and hand-making) carbon panels purely as a way to lighten up the S15. Now it’s about improving aerodynamics and increasing downforce, and there’s a whole lot more work that he wants to. “It takes a lot of time to produce these parts,” says Suzuki. “In a year I can only make one or two pieces, so I think I’m going to need about three more years to complete the whole body.”
Like the bodywork, Suzuki-san can be credited with the S15’s engine build. Using the Nissan’s stock SR20DET mill and mating it with a NEO VVL head from a Nissan Primera, he has effectively built an “SR20VET”, although this one’s a slightly more serious piece of hardware than the factory 276hp variant Nissan cooked up for its JDM-spec X-Trail GT. The NEO cylinder head has not only added variable valve timing and lift into the mix, but out of the box its flow and cooling characteristics are much improved over the SR20DET version. In an effort to squeeze every last drop of potential out of the head, however, Suzuki-san handed it over to the engineers at Nagoya Precision (aka NAPREC), who CNC-machined the combustion chamber and upgraded its valvetrain to suit. Down below the SR20DET block had its internal organs pulled and replaced with race-grade gears from the Brian Crower (BC) catalog. A BC 4030 steel billet crankshaft is in place, as are BC H-beam connecting and BC forged pistons, resulting in a bulletproof package that now displaces 2.2 liters.
The power-making part of the equation is a fresh turbo arrangement built upon a GCG/Garrett GTX3582R. Key ingredients in the set up include an iR exhaust manifold, Blitz air-to-air intercooler and a Turbosmart Comp-Gate external wastegate for boost control. On the intake side of things, the SR uses a Hypertune manifold and 80mm throttle body, with fuel delivered by a bank of Bosch 1600cc top-feed injectors fed via a Hypertune fuel rail, Turbosmart regulator and a GCG/Deatschwerks high-flow pump. On the exhaust side Suzuki-san fabricated both the front pipe and the lightweight, and sweet-sounding titanium exhaust system. Elsewhere there’s a Hi Octane Racing dry sump kit for reliable lubrication and a parallel-mounted aluminum radiator for cooling.
Tuned through an HKS F-CON V-Pro and with 2.5kg/cm2 (approx. 35.56psi) of boost pressure dialed in, Suzuki-san estimates the sum of the all the engine parts at approximately 800 horsepower. That’s a couple of hundreds ponies short of his ultimate goal with the SR engine, but no shortage of grunt for a chassis that tips the scales at not much more than 2,200 pounds. Of course, having all the power in the world is one thing, but to go fast you need to get it to the ground. Suzuki-san definitely didn’t skimp out when piecing together a driveline up to task. In fact, he bought some of the best hardware money can buy including an Holinger RD6 six-speed sequential transmission running though an ORC triple-plate clutch and out to a NISMO GT Pro limited slip differential.
Although simple in its make up, the suspension and brake systems have been extensively upgraded for racing duty. Bilstein coilover shocks wrapped in Hyperco 12kg springs are featured on all four corners and all of the car’s OEM arms have been modified with spherical ends. In the brake department 13.5-inch Garland two-piece rotors fitted with four-pot Brembo monoblock calipers are used at the front end, while Garland 12-inch rotors with BNR32 GT-R two-calipers suffice at the rear. Endless’s new Type-R pads are employed throughout.
Engineering a car with the potential to beat one of time attack’s all-time greats at its own game is no mean feat, but for Under Suzuki it’s taken untold time, untold dedication and every yen he’s earned over and above his living expenses. But we get the feeling that he’d do it all over again in a heartbeat. “I’m grateful to everyone. I’m just an office worker and I neither have my own garage, nor enough money to rent a place to work on the car. My free pit is the Scorch Racing garage and I go to another body shop to make the carbon parts for my car. I have friends lending me a truck when I need to get the car to the circuit. My friends help a lot and without them I wouldn’t be what I am today. Thanks to them I am able to keep on doing time attack.”
Between events, however, there’s still plenty of work to be done according to Suzuki-san: “I need to finish the aero kit and get more downforce. I want more power and I think there is a lot to be improved in corner speed, so I need to make changes to the suspension geometry too. I think this will take another four or five years. My car is not nearly finished yet…”
Scorch Racing Nissan S15 Silvia
Engine Nissan “SR20VET” Kai 2.2L; BC 4030 billet crankshaft, H-beam connecting rods, forged pistons; SR20VE NEO VVT cylinder head; NAPREC CNC-machined combustion chamber, metal head gasket, cylinder head bolt kit, ATI damper pulley kit, valve springs and valve guides; Bosch 1600cc top-feed injectors; Hypertune fuel delivery pipe, intake manifold and 80mm throttle body; Turbosmart Race Port blow-off valve, adjustable FPR and Comp-Gate external wastegate; Blitz intercooler; GCG/Garrett GTX3582R turbocharger; iR exhaust manifold and megaphone pipe; GCG/Deatschwerks fuel pump; NGK Racing spark plugs; Hi Octane Racing dry sump kit; parallel-mount aluminum radiator; custom stainless steel front pipe; custom titanium exhaust system
Owner Tomohiko ‘Under’ Suzuki
Drivetrain Holinger RD6 6-speed sequential transmission; ORC triple-plate clutch; NISMO GT Pro limited slip differential; 4.08:1 final drive
Engine Management HKS F-CON V-Pro
Footwork & Chassis Bilstein adjustable coil-over dampers; Hyperco 12kg springs front/rear; pillow ball modified OEM suspension arms; rigid chassis member
Brakes Front: Garland 342mm two-piece rotors, Brembo forged monoblock 4-pot calipers, Endless Type-R pads; Rear: Garland 300mm 2-piece rotors, BNR32 Nissan Skyline GT-R OEM 2-pot calipers, Endless Type-R pads
Wheels & Tires 18x10.5" + 18 Volk Racing RE30 wheels; 295/30R18 Yokohama ADVAN A050 GS tires
Exterior Custom made dry carbon aero kit: fenders, bonnet, front bumper, canards, front under spoiler, rear spoiler, carbon-fiber roof skin, doors; Scorch Racing GT Wing
Interior 14-point chrome-moly steel rollcage; Recaro SPG driver seat; dry carbon dashboard; Nardi suede 340mm steering wheel; Racepack IQ3 dash logger