Sci-fi writers are obsessed with the idea of opposite dimensions. A character in one dimension is the consummate good guy. Fighting for justice, he's a peaceful warrior at heart, always on the side of righteousness. In the opposing dimension there's the villain, the scoundrel, Spock with a goatee. Aside from subtle differences in facial hair, writers tend to make the characters look the same. They apparently lived similar lives that brought them to the same point in time and space where their respective dimensions overlapped through a temporal rift or a man-made portal. At some point, the two opposites must battle it out to save or enslave humanity. Generally the good guy wins, but who says our perception of the universe works in every dimension?
In a blistering hot Southern California Canyon we let two polar opposites like this duke it out for superiority. Both cars are examples of GMG Racing's WC Tuning program. Running a three-car team in World Challenge Racing has led GMG to develop its racing parts for use on customer cars. Everything from suspension to exhaust has made the transition from the track to serious street performance.
GMG focuses the majority of its attention on suspension tuning. On the track, adjustability and consistency are key to fast lap times. Adjustability is obtained by replacing Porsche's fixed-length linkages with fully adjustable pieces that allow for both static and kinematic geometry tuning. For consistency, GMG replaces all the soft rubber bushings with spherical steel bearings. Ridding the suspension of deflection ensures that everything stays were it was intended to be under heavy loads.
The black GT2 uses factory springs and dampers, while the white GT3 has attained the next level with Eibach springs and Moton adjustable dampers valved to GMG specs. Both cars use GMG anti-roll bars front and rear that allow fine-tuning the handling balance. The GT3 also uses Porsche Motorsport uprights used on Rolex Series cars. The recalibrated units alter the suspension's roll-center, changing lateral weight transfer for more aggressive cornering.
Readers should be warned that most of the suspension parts found on these cars aren't for the average guy just looking to blow some money to impress his neighbors. These are race grade parts that require professional install, set-up and maintenance. If you spend as much time sitting on the Starbucks patio staring at your 911 sipping your Dopio Machiato as you do driving it, these parts aren't for you.
Something everyone can appreciate, however, is exhaust modifications. The GT3 uses GMG's sport center section that not only adds a few horsepower but shaves 12 pounds of weight. It is completely emissions legal and even works in conjunction with the car's Sport button. The GT2 is a little more involved, the exhaust manifolds replaced with free-flowing 3-into-1 headers using F1-style merge collectors in front of the turbos. Downstream is GMG's WC titanium sport exhaust, which uses a proprietary crossover section. GMG is currently trying to patent this novel design. Both systems add a noticeable amount of anger to the cars' voices without overpowering the passengers inside.
For the real power bump, GMG worked with GIAC to develop software that works in tandem with the other mods. The GT3 gains a modest but noticeable 18 hp and 21 lb-ft of torque. The monster GT2, on the other hand, rips off 680-hp and 700-lb-ft runs on the dyno. Apparently the car was able to run up to 695 hp and 720 lb-ft, but in the interest of mechanical preservation it was dialed back slightly to keep the engine internals where they belong-inside the engine.
It may sound like these two cars have similar manners. Sure, the GT2 has more power and the GT3 seems a little more developed in the suspension department, but only incrementally. Kind of like two fighters, one being slightly bigger and the other having better technique. Both have their strengths, but neither a clear advantage.
In the canyon arena we learned the true story. Both cars lived up to their appearance. The GT2, dripping evil with deep black paint, aggressive wing and huge rear tires looks as if it should be carrying a battle-axe in the rear window. The GT3, shining in bright-white paintwork, huge Brembo brakes and more balanced tire package looks lithe and agile, a martial artist. The GT2 strikes right out of the gate with huge power. It shoots down straights like a leopard jumping point to point. The turbos spool quickly and power surges in huge impulse waves. It wears 235mm tires on the front and 335s on the rear, a hint that this car is all about acceleration. It uses all the rear tires coming out of turns, to the point that you don't want to get on the throttle too early for fear of flight. The question is whether you will be flying forward or backwards.
The GT3 wears 265s in front and 305s out back. The front fenders are custom carbon-fiber panels that allow the fitment of a 10-inch-wide wheel. That much tire allows for the massive force of the Brembo GTR F1 brakes to be fully exercised. At the same time, it equates to a car that is extremely well balanced, where turn-in is sharp and mid-corner balance is neutral. Power delivery is smooth and predictable; it doesn't feel as binary as the GT2. Power can be fed in slowly and evenly. The GT3 is so supple, and communication so intense, the driver feels as though he's micromanaging each tire, giving specific instructions to each tread block. The GT2 is more battle-axe swung with two hands in giant circular swathes; the GT3 is a Samurai's katana gliding through the medium without resistance. The difference is astounding and fascinating all at the same time.
The GT3 feels like it would be at home on tight, technical tracks, snipping apexes down to the millimeter. It wants to run all day, never barking rubber and never going out of shape, just surgical precision and preservation. The GT2 wants room to run, big straights where it can pound other cars into submission. It wants long, sweeping turns, increasing radii to power out of, a sprint race where it can chew up tires and competitors alike.
The two cars are an amalgamation of everything GMG has learned on track. GMG's World Challenge Race Drivers, James Sofronas, Dino Crescentini and Sean Allen, have been the ultimate development team. Hours on the track have allowed them to take the brute power of the GT2 and build an untamed barbarian. The GT3 is the White Knight, cultured and refined yet still thoroughly capable.
Which side are you on?
2008 GMG WC Porsche 911 GT3
Longitudinal rear engine, rear-wheel drive
3.6-liter flat six, dohc, 24-valve.GIAC software with custom calibration for use with exhaust mods, 91/93/100 octane programs. GMG sports exhaust center section with 3.5-inch tips.
Six-speed manual with GMG WC limited-slip differential upgrades
GMG/Moton two-way adjustable dampers, Eibach ERS Springs, GMG World Challenge anti-roll bar set (front and rear), Porsche Motorsport Rolex uprights, adjustable rear control arms, GMG GT Dog Bone kit, GMG toe steer kit rear, GMG bump steer kit (front), GMG adjustable thrust arm bushing kit
Brembo GTR F1 eight-piston front calipers, 15-inch rotors and hats with titanium hardware, Brembo GTR F1 rear four-piston calipers, 15-inch rear rotors
*Wheels And Tires
BBS Motorsport three-piece racing alloys (as used on the GMG World Challenge Cup cars), 10x19 (f), 12x19 (r)Michelin Pilot Sport Cup, 265/30 (f), 305/30 (r)
GMG World Challenge carbon front fenders, carbon wing blade, 15mm rear wicker, GMG World Challenge front radiator exhaust vent grille, carbon mirrors, Motorsport GT3 Cup front chin spoiler, flat panel undertray with integrated NACA ducts
Carrera GT carbon seats, GMG GT Cup harness bar, carbon interior package, Sparco competition harnesses
2008 GMG WC Porsche 911 GT2
Longitudinal rear engine, rear-wheel drive
3.6-liter flat six, dohc, 24-valve. Twin turbocharged, custom GIAC software with stock/91/93/100-octane and valet modes and GIAC handheld switcher, GMG WC-GT sport exhaust with four-inch tips, proprietary crossover center section, WC-GT sport exhaust manifolds with F1 collector, GMG WC intercooler set with boost hoses
GMG WC sport anti-roll bar set, GMG WC Dog Bone kit, GMG thrust arm bushing kit, GMG toe steer kit, GMG bump steer kit, Porsche Motorsport rear adjustable control arms, Competition alignment and corner balance, ride height set to European specifications 10mm lower.
*Wheels And Tires
BBS Motorsport three-piece racing alloys, 9x19 (f), 12.5x19 (r)Michelin Pilot Sport Cup, 235/35 (f), 335/30 (r)
GMG WC Rear carbon replacement wing blade, WC replacement carbon chin spoiler
GMG WC-GT harness bar