The Sport Auto Tuner Grand Prix is held at Hockenheim at the end of May every year. This spectacular event sorts the men from the boys amongst the tuners, and overall and class winners get to take home a nice trophy and retain bragging rights for a whole year. Cargraphic has won the event's GT Class three times with naturally aspirated GT3-based cars, and last year its Turbo GT RSC 3.6 finished a close second.
So what does it take to chalk up a TGP win? Hockenheim's short Club Circuit is handling biased, so your chassis setup has to be spot on. Cargraphic's first three wins proved that big turbo power alone does not cut the mustard, especially when it rains. Power helps, but ultimately, a good overall balance between chassis and engine and top-notch driver skills are the essential ingredients.
In stock form, Porsche's 911 Turbo is quick, but it's also heavy and has too much understeer in tight bends and too much weight transfer under hard acceleration and braking to be totally effective on track. Cargraphic works on all sides of the equation, shaving weight, adding power and uprating the suspension.
Thanks to forged alloy wheels, carbon-fiber front bonnet and wider fenders, carbon doors incorporating Porsche's side-impact bars, lightweight sport seats, door panels, carpets and no back seat, the GT RSC 3.6 ends up 150kg, or 330 pounds, lighter. The front spoiler lip that provides 10kg of extra downforce, the side air intake frames and the rear Gurney are all carbon-look.
The engine work consists of a free-flow air filter, modified intake manifold, modified VTG turbochargers, new larger-diameter air pipes, high-efficiency intercoolers, new inlet plenum, sport exhaust with 200-cell metal catalysts and a remapped ECU.
The power target was 600 hp, so you can bet they were pleased when the dyno sheet showed 618 hp at 6500 rpm, with 623 lb-ft of torque from 2500 to 4750 rpm. That translates to over 400 hp per ton, and requires a race clutch to reliably feed power to the stock six-speed manual gearbox.
The Turbo is a launch-meister, with 62 mph taking just 3.8 seconds thanks to its all-wheel traction. The Cargraphic machine chops half a second off that time, which requires considerable driver skill with the clutch and Cargraphic's 35 percent short-shift-enhanced gear lever. But the real difference becomes apparent when you move into the higher speed ranges where the GT RSC's bigger lungs have the chance to breathe deeply.
A 100-mph sprint that takes 8.6 seconds in a stock Turbo is now covered in just 7.1 seconds, and the gap widens as the speedo needle moves further clockwise.
By 160 mph, the GT RSC is a yawning 4.6 seconds ahead as the stopwatch reads 18.4 seconds. To put that in perspective, consider the fact that any normal family sedan or hot hatch that can break 20 seconds to 100 mph is considered quick. Eventually, the rev limiter calls a halt to the proceedings at 326 km/h, or 203.75 mph.
The old Pirelli adage that "power is nothing without control" comes to mind again when it comes to deploying the power effectively. Cargraphic works closely with Bilstein on all its suspension kits, and uses a coilover suspension that can be adjusted for ride height, bounce and rebound. They also fit a strut brace to help maintain front-end geometry under high cornering loads.
Alloy wheels are another Cargraphic cornerstone, and this car is fitted with the company's RG-5 forged one-piece wheels in 9.0 and 12.0x19-inch sizes, wrapped in 265/30ZR19 and 315/30ZR19 Dunlop rubber.