The 2010 Carrera Cup season looms and Porsche has readied their latest weapon for the race season, the 911 GT3 Cup Car. Porsche is unique in that it has integrated its Motorsport division into its R&D and production facility. So with the introduction of the latest 997 cars earlier this year, it is not surprising to find the Cup Car being introduced as well.
The new 2010 911 GT3 Cup car is now about 0.3 seconds per km quicker than the outgoing one and at Hockenheim is worth around 1.5 seconds each lap. This is achieved by improvements in three key areas, engine, aerodynamics and handling.
Porsche has focused its efforts on the new 3.8-litre flat-six derived from the current GT3 RS, tweaked to produce 450 bhp. It is still using port injection at this time and the Motorsport division is looking hard at Direct Injection as a solution for the next gen race car. The key to better performance is not so much the increase in horsepower but the wide spread of torque. With the Carrera Cup regulations mandating a fixed set of gear ratios it is likely one will not have the optimum set of gear ratios for every track. Having a wide spread of torque allows the driver to get out of corners in a taller ratio and not be much slower.
Porsche has also fitted as standard a catalytic converter to protect the environment. The exhaust system is fairly quiet as far as race cars go but ensconced inside the cabin you would be none the wiser. Not because it is quiet but the tremendous cacophony of sounds from the race tyres, rose-jointed suspension and straight cut gears of the sequential gearbox drowns out the exhaust noise and conspires to deafen you even with the race-helmet on. There is no respite from the noise because despite the aural over-stimulation your body refuses to get out of the OMP carbon-fibre race seat. Of course you tell yourself it is because the 5-point harness is far too tight to unhook by oneself but you know addiction has set in and you would like another ten laps.
If one is addicted to high g-forces the new Cup Car supplies that in shiploads. The on-board telemetry indicates it delivers nearly 1.5g during braking and cornering which does not adequately describe the sensation of one and a half times your weight squashing your rib cage and hip bone into the side of the unyielding carbon fibre race seat. One really needs to be fit for this sort of activity or suffer the painful consequences.
With sticky Michelin slicks it is indeed fortunate that the steering is sufficiently assisted so piloting this cup car a breeze until you realize a normal three point turn requires five or six attempts instead because the turning circle is huge. This also effects one's ability to collect the car once it spins so it is best not to let it get too far out of shape before catching it.
Remarkably it is genuinely difficult to make this 911 want to spin as the engineers have nailed down what it needs to keep the pendulum weight of the engine from wanting to swap ends with the front. The level of tactility from being strapped into the center of a deep bucket seat is just marvelous as you truly become one with the car in its every movement. With the steel rose-jointed suspension mounts every nuance is fed so clearly to the driver through not just the seat of his pants but one's entire body as well.
With the half-inch wider rims up front and the one-inch wider rims at the back the tyre sidewalls are stretched to assume a more vertical or in this case more than vertical profile that makes the sidewalls behave as if much stiffer without any additional inflation pressure which can then be kept at a race-temp 2.0 bar. This optimizes the contact patch of the Michelin race rubber which happens to be exactly the same as last year's.
The weight of the Cup car in race trim is just 1200 kg and with the Supercup spec PCCB (Porsche Carbon-Ceramic Brakes) the weight is a lithe 1180 kg. This next Cup car has gained 50-kg mainly because of the new 44mm wider bodyshell based on the new GT3 RS but is more than mitigated by the better dynamics a wider chassis brings. Just point the car and it literally jumps into position without yaw nor roll, that is how responsive this lightweight racer is. Even more remarkable is the stopping ability of these endurance-regulation large-diameter steel disc brakes. They use the floating disc design and they are fade free even at race pace, negating the thermal advantage of the hugely expensive PCCB items except for the 20-kg unsprung weight savings.
Braking is this car's forte and it is almost ridiculous just how late one can leave the braking and still get away with it. Having the weight of the engine hanging out the back certainly isn't helpful during a spin but is perfect during braking, making the rear brakes work as hard as the front ones delivering nearly 50% more stopping power over a FWD car.
Brake bias is near perfect and is fixed by Porsche for the Carrera Cup regulations as are items like brake pad material, damper settings, spring rates, gear ratios and engine power. This ensures every competitor gets the same car and hence is mostly through the effort of the driver should he win a race.
There are things open to him to tweak in the suspension and aerodynamic areas. The suspension is fully adjustable for toe, castor, camber, ride height and corner weight balance. Even roll stiffness is adjustable via a seven position blade type end on both sides of each roll bar. And of course so is the tyre inflation pressure to fine tune handling.
The new 24mm wider rear aerofoil is rake adjustable to balance overall downforce that has increased some 15% over the previous car which is interesting as the front does not appear to have been altered that much. Just two items produce the added front downforce, a front spoiler lip extended 15mm closer to the ground and a pair of carbon fibre gurney flaps just before the wheel arches help alter airflow around the wheels without increasing overall drag.
There is no doubt grip levels are phenomenal but the new Cup car also serves up more benign handling, It was an area that Motorsport Engineer Owen Hayes proudly proclaims as an achievement because combining easier-handling with better lap times is not an easy task. However this was done to make it easier for newbies to get comfortable with the Cup car so as to quickly match the existing lap times and at the same time still thrill the existing jaded Cup Car clients, all with the intention of fostering closer racing.
Handling is quite neutral and presents a fairly broad region where the car seems to get into a groove, where the steering stops fighting you, where the yaw rate seems equal to the bend and the car seems to flow through the corners. The first few times you reach this point will give you the willies because it is the usual sensation just before a spin. However the GT3 Cup car is extremely faithful in its response and communication and so one learns not just to live on but to seek out this fine edge. After ten familiarization laps, it took me a further three hot laps to get my best laps out of this car. It is by no means an easy feat but is most certainly a rewarding one.
CAPACITY : 3456cc
CYLINDER LAYOUT : V6
VALVES : 24 valves
BORE X STROKE : 94x83mm
COMPRESSION RATIO : 10:1
MAXIMUM POWER : 280 PS at 6400 rpm
MAXIMUM TORQUE : 350 Nm at 4700 rpm
TYPE : 6-speed manual
DRIVEN WHEELS : Rear
TOP SPEED : 261 km/h
0-100KM/H : 5.1 seconds
FRONT : Double wishbones
REAR : Double wishbones
FRONT : Ventilated Discs
REAR : Solid Discs