Corvette C6.R GT
The Chevrolet Corvette C6.R GT (also known as the Corvette C6.R ZR1) was the race-going equivalent of the Chevrolet Corvette C6 ZR1. The C6.R GT was constructed by Pratt & Miller and ran by Corvette Racing to compete in the GT2 class (later renamed GT in ALMS and GTE Pro at Le Mans) of the American Le Mans Series and the 24 Hours of Le Mans. The GT2 version of the C6.R was built in 2009 and made its debut half way through the ALMS season. With the global financial crisis affecting the automotive industry hard, the GT2 class was a cheaper and more competitive option for Corvette Racing, especially seeming the competition in the GT1 class had diminished. The GT2 C6.R showed good pace in its debut however the rules would restrain it from being as dominate as its GT1 counterpart.
In 2009 the unthinkable would happen when General Motors as one of the worlds largest and most powerful automotive companies, declared bankruptcy on June 1st. With $82 billion in assets and $173 billion in liabilities it would become on of the largest industrial bankruptcy in history. This left a lot of questions of what would happen to the Corvette Racing program and the Corvette brand. Corvette sales had dropped by 52 % from 2008 and with most companies freezing all credit, leasing being suspended, sales worldwide were down which led to a reduction in price for Corvette.
The automotive industry was struggling in the financial crisis, which ultimately was affecting motorsports. This left a lot of car manufactures in a difficult position due to the huge financial investment of motorsports that returns global reputation, advertisement and brand recognition. The governing body of most of the major motorsport series the Federation Internationale de l’Automobile (FIA) made some changes to keep competition alive along with the reduction of costs. The sanctioning body of Le Mans, the Automobile Club de l’Ouest (ACO) decided to eliminate the more expensive GT1 class by 2011, requiring any GT cars to be built to the cheaper GT2 specifications. The support amongst manufactures for the GT2 class was still strong with some of the worlds largest brands such as factory efforts from Ferrari, Porsche and BMW.
The GT1 class in the ALMS had shown a decrease in competition from 2007, with Corvette Racing only facing two other competitors during the 2007 ALMS season and one competitor in 2008. The C6.R had become a dominant GT race car and Corvette Racing had become one of the most successful GT racing teams in the world. This was part to blame of the demise of the GT1 class as the manufactures didn’t want to be embarrassed anymore. The lack of competition had led to very little air time on television for Corvette Racing in 2008, which combined with the expense of GT1, led to the decision for Corvette Racing to transition to GT2.
The 2009 season started with Corvette Racing using last years GT1 chassis of C6R-007 and C6R-008 as the team wanted one last go at a GT1 win at Le Mans to end the program on a high. This would lead to the new GT2 equivalent C6.R to debut at round six of the ALMS season at Mid-Ohio.
For the GT2 C6.R, it wasn’t as simple as lowering the hp output and changing the aero package, Pratt & Miller had to construct a completely new car. The GT2 class rules require a much closer production specification race car compared to GT1. Although the GT1 version of the C6.R was based on the Z06, the aluminum chassis of the Z06 was decided against with the steel uniframe of the base C6 Corvette being used instead. For GT2, the aero package was heavily restricted compared to the GT1 rules. This left Pratt & Miller to make up for the loss of downforce with the increase in mechanical grip, therefore the the decision was made to use the stiffer aluminum frame used on the production Corvette Z06 and ZR1.
To help Corvette Racing transition quickly to the GT2 class, the Katech developed LS7.R of the GT1 C6.R was permitted but was forced to reduce its displacement from 7.0L to 6.0L. Katech would continue to build and maintain the LS7.Rs of the C6.R up to the end of the 2009 season. GM would take over from 2010 with in-house developed race engines based on the LS7.
The new GT2 C6.R made great impressions within its first few race. In its debut the GT2 C6.R was able to finish second in class behind the Flying Lizard Porsche. In its second race the team accomplished another class podium, crossing the finish line in third place. It would only take three races for the new GT2 C6.R to take a class win, which happened at round eight of the ALMS season at Mosport.
The switch to GT2 for Corvette Racing not only allows for lower costs, but the high global use of GT2 specification race cars, opened a bigger market for Pratt & Miller to sell used GT2 C6.Rs to privateer teams. Overall the transition to GT2 for GM, was a far safer financial move.
The next two seasons would be a struggle for Corvette Racing, leading to some of the worst results in Corvette Racing history. The attitude and persistence of Corvette Racing eventually led to the team returning to the podium, allowing them to collect championships in 2012 and 2013.
The previous GT1 C6.R was based on the production Z06, which featured a new aluminum frame. Despite the advantages of the use of an aluminum frame, Pratt & Miller decided for safety reasons to use the steel frame from the base model C6. The GT2 class rules enforced a lot more use of production based components. This included the use of the factory floor plan, transmission tunnel, firewall, windshield frame, B-pillar halo, and the door hinge pillars. The ACO and FIA required that GT2 cars had to maintain the primary production structure of the chassis. In contrast, the GT1 rules allowed for those same components to be modified, including trimming down or even completely remove them altogether.
The aluminum frame did pose challenges for Pratt & Miller when it came to mating it to a steel roll cage. Safety has always maintained a priority over performance for Corvette Racing. Safety equipment that was not mandatory had featured on the GT1 C6.R, despite the extra weight it added. The team was concerned by the potentially weaker welds between the steel and aluminum materials, but after physical testing and analysis of the structural components, the results proved that the GT2 C6.R was the safest GT car on the track. Pratt & Miller carried over from the GT1 car the drivers side energy absorbing crash box, the door bar structure, the energy absorbing panels, and the right side window net despite the GT2 rules did not require them.
The ZR1 chassis really impressed the team with its on track performance. The GT1 category allowed the use of a large aero package to capitalize on downforce. For GT2, the FIA required the use of a much smaller front splitter, a lower and shorter rear wing and a more simple rear diffuser. This put more pressure on a constructor to utilize mechanical grip, which is generated from the chassis, suspension and tires. The use of the ZR1 chassis in the GT2 C6.R was much stiffer therefore it created a big increase in mechanical grip over the previous GT1 steel chassis. After initial testing, the team announced that the GT2 C6.R produced the most mechanical grip than any other race cars they had previously built.
Katech had been the engine builder for Corvette Racing from the beginning. Their engines had performed flawlessly with the LS7.R in the C6.R collecting the award of Global Motorsport Engine of Year 2006. Katech remained the engine builder for the GT2 car in its debut season in 2009, but due to the pursuit of keeping costs down, GM took over in 2010 with a in-house operation.
The LS7.R used during the 2009 ALMS season met the GT2 regulations by Katech reducing the displacement from 7.0L to 6.0L. Katech achieved the decrease in displacement by shortening the stroke of the crankshaft from 3.875 inches to 3.32 inches. The smaller displacement alone did not reduce the power output enough to meet the GT2 regulations, therefore the mandatory 30.6mm air restrictors were reduced to 28.6mm limiting performance. The result to the changes of the LS7.R was the original 590hp output was reduced to 470hp and the torque figures saw a reduction from 640lb-ft to 535lb-ft.
Although the GT2 spec C6.R was based on the C6 ZR1, the supercharged LS9 was not permitted by the FIA. The GT2 engine regulations changed in 2010, enforcing the maximum size of 5.5 liters for naturally aspirated engines or 4.0 liters for forced induction engines. After a decade of Katech building the Corvette Racing engines, GM took over in 2010 as an in-house engine building operation. The 5.5L GM V8 engines were built at the Wixom Performance Build Center, the same location the factory Corvette engines are built. The smaller 5.5L V8 was built from the LS7 platform and despite lessons learnt from Katech, it did not have an easy introduction. During its first 24 hour race at the 2010 Le Mans 24 Hours both cars suffered engine failure forcing the first full retirement at Le Mans for Corvette Racing.
The 2010 5.5L GM V8 differed from the 2009 6.0L Katech engine by reducing the crankshaft stroke to 3.185 inches allowing for the reduction in displacement, however in 2012 the air restrictors saw an increase from 28.6mm to 29.2mm. Overall the 5.5L GM V8 created a power output of 491hp and 485lb-ft of torque. The GT2 rules allowed for higher rev limiters so the GT2 C6.R saw an increased shift point of 6,400rpm compared to the 5,700rpm of the GT1 C6.R.
The 2009 GT2 C6.R continued to use the same Xtrac six-speed sequential transmission from the previous GT1 car. This was controlled by a single lever located in the same slot of the transmission tunnel where the regular Corvette C6 gear lever would be located. The sequential shifter was made by Hurst, which was longer than a standard shifter and tilted to the left towards the driver. This made for better ergonomics as it was shorter distance for the drivers right hand to travel from the steering wheel to the shifter. A simple pull back on the shifter engaged an upshift and a push forward on the stick allowed for downshifts.
In 2011 the FIA changed the rules making paddle shift operated transmissions legal in the GT class. Pratt & Miller started testing the paddle shifters at Road Atlanta in late 2010 for the upcoming season. The move to paddle shifters was not overlooked for Corvette Racing as it allowed for slightly quicker gear changes but also when set up properly, helped minimize wear and tear on the drivetrain.
The move to paddle shifters created new technological challenges for the Pratt & Miller engineers. The electronics of the C6.R had to be programmed for gear changes to allow for fuel cut and spark cut with precise timing. During downshifts the electronics also matched speeds, essentially eliminating the need of the heel and toe braking technique. The paddle shifters were far more accurate and almost completely removed the risk of human error within gear changes.
The sequential transmission used between 2009 -2010 required the use of the clutch pedal and or the use of manual rev matching during downshifts. The transition to paddle shifters meant the use of clutch pedal was only required for moving from a stand still. This freed up the drivers left foot to be dedicated to the brake pedal only, which allowed for the preferable left foot braking technique. With the correct use of left foot braking faster lap times can be achieved as the delay of the right foot moving from the throttle pedal to brake pedal is eliminated. This opens up the option for the left foot to be applied to the brake pedal at the precise moment the throttle is released. The left foot braking technique can also be used to control body roll under heavy braking via the use of simultaneous pressure applied between the brake and throttle, which decreases the weight transfer to the front axle. Overall paddle shifters on a race car feature the most benefits over the use of any other style of transmission.
The overall dimensions between the GT1 and GT2 C6.R differed more visually than the specific measurements. Like the GT1 class a production chassis was used therefore the wheelbase remained unchanged at 105.7 inches. However with the GT2 class requiring a much closer production foundation over the GT1 specifications, so the overall length of the GT2 car decreased by 2.5 inches. This was due to the much smaller aero package of the GT2 car with the front splitter of the GT2 car being almost identical to the one used on the production Corvette C6 ZR1. This front splitter was far smaller than the GT1 splitter. This shorter overall length of the GT2 C6.R matched the same overall length of the production Corvette ZR1 at 176.2 inches.
The width of the GT1 C6.R was 78.6 inches, which was an increase of 2.8 inches over the production Z06 it was based upon. The GT2 C6.R saw a decrease in width by only 0.1 inches purely due to the use of aggressive flared fenders. The body of the GT2 car was identical to the production ZR1, minus the 2.7 inch flared fenders. This differed a lot from the previous GT1 C6.R that had a bespoke body that was built to simply resemble the Z06.
Finally the overall height of the GT2 C6.R sits a whole 2.8 inches lower than the production ZR1. This height remained identical to the height of the GT1 C6.R. The fully adjustable suspension allowed for the ride height to be increased or lowered per wheel to meet demands of the diverse tracks on the ALMS calendar.
The Corvette C6 ZR1 tipped the scales at 3,353 pounds (1,521 kg). Despite the use of a lot of carbon fiber the supercharger and intercooler added over 200 pounds to the ZR1s weight over the Z06. The GT2 C6.R sheds a whole 608 pounds (275.8 kg) from the weight of the production ZR1. This is created by the elimination of a lot luxuries the road car has that has no purpose on a race car, such as the leather / heated seats, sound deadening, heat shielding, entertainment and sound system. The body of the race car is made of carbon fiber and kevlar with the side and rear window being made of lightweight polycarbonate.
Despite the much lower weight of the GT2 race car over its road going equivalent, the GT2 C6.R increases in weight by 165 pounds (74.8 kg) from the previous GT1 car. The increase in weight is made up by the GT2 rules requiring the use of the production laminated glass for the front windshield in contrast to the polycarbonate windshield used on the GT1 car. Along with the heavier windshield, weight was added due to the wheels no longer being allowed to be constructed from magnesium as the rules enforced the use of heavier aluminium wheels instead. The steel brake rotors of the GT2 class also added weight over the carbon ceramic brakes equipped to GT1 C6.R.
The C6.R GT2 weighs in at 2,745 lbs (1,245 kg) including driver and fluids. Overall the increase in weight, lower power output and decrease in downforce made the GT2 spec C6.R an average of a 4.8 seconds a lap slower than the GT1 predecessor.
The most noticeable difference between the GT1 and the GT2 C6.R was the aesthetics of the bodywork. The original GT1 car was based on the Z06 road car, however the GT2 version was homologated on the ZR1 road car. Where the GT1 car resembled the Z06, the GT2 rules require the use of the production-type fenders with simple fender flares accommodating wider tires. This made for a much more production looking race car.
The GT1 rules allowed for Pratt & Miller to section and widen the fenders. The result of this was the overall design of the GT1 C6.R was much wider than any other Corvette. The wide design of the GT1 C6.R threw off the proportions of the factory parts such as lights and grille. This led to Pratt & Miller constructing their own headlights that were simply based on the factory C6 design but were much larger. The size of the front grille was increased along with the fog lights. On the rear fascia the gaps between the taillights was much larger helping maintain a factory look.
When it came to Pratt & Miller deciding on which model of Corvette to base the GT2 car on, they looked at the base Corvette coupe with the steel chassis and narrow bodywork as well as the Z06 and ZR1 variants with their aluminum chassis and wider bodies. The team ran a number of simulations and CFD (Computational Fluid Dynamic) studies, which compared the difference between the wide and narrow bodies. The designs also allowed the team to observe benefits of the various track width options with the end results proving the data favoured the wider car.
The team saw benefits of the ZR1 design as it featured a unique high-speed aero package unlike any other model of Corvette. The ZR1 road car was designed to exceed 200 mph therefore within its development Corvette chief engineer Tom Wallace and Tadge Juechter worked with the Corvette Racing engineers. The engineers were able to obtain CFD simulations and track data from the race cars and together an effective and balanced aero package for the production ZR1 was developed. The final aero design of the ZR1 featured a package unlike any other Corvette model, including a carbon fiber front splitter, carbon fiber side skirts and a full width unique rear spoiler. The ZR1s wide carbon fiber front fenders with dual vents along with the aero package enhanced the high-speed stability and the on track performance. This led to the decision for Pratt & Miller to use the ZR1 as the GT2 platform as its design overall enhanced the C6.Rs aerodynamic performance.
The GT2 C6.R was unable to have a wind tunnel model due to the limited timescale and smaller budget therefore CFD became the primary tool to develop the aero package. Corvette Racing engineering director Doug Louth explained that the team performed high-speed straight-line tests and conducted a full-scale rolling-road wind tunnel test during the validation phase. They carried out all the aerodynamic tuning options at the track, which resulted in the baseline aero settings meeting all their performance targets. As the aero package was developed, the team went through a number of reviews with the Corvette design group as they were interested in what could be taken away for future Corvette models. This created a two-way exchange of concepts and ideas, which proved to be a very rewarding relationship.
The GT2 rules mandated a much stricter aero package compared to GT1. The large 80mm (3.1 inch) front splitter of the GT1 car was not allowed in GT2, therefore the GT2 C6.R utilized the design of the production 25mm (1 inch) ZR1 front splitter. The front fenders of the GT1 car featured full length louvers designed to reduce front end lift, but the GT2 rules did not permit the use of fender louvers. The rear wing had to be mounted much lower than the GT1 wing and featured a shorter distance from the leading to trailing edge known as chord width. In comparison to the GT2 wing was reduced by 25% over the GT1 wing, an overall reduction from 400mm (15.7 inches) to 300mm (11.8 inches). Finally the complex design of the GT1 rear diffuser had to be simplified and shortened to meet the GT2 regulations. The previous GT1 diffuser started at the rear axle centerline and featured side walls with strakes that created 14 venturi tunnels. The GT2 diffuser had to be shortened, starting at the back of rear wheel opening and was completely flat with no strakes nor side walls.
The restricted GT2 aero package produced a loss of total downforce over the GT1 car, however Corvette Racing program manager Doug Fehan reported that the GT2 was more predictable over a wide range of speeds. The GT1 car produced a tremendous amount of downforce, but the level of downforce was directly proportional to the speed. In slow corners the downforce was low making the car behave differently than it did in high speed corners with more air traveling over it. This forced the drivers to adjust their driving styles depending on the level of grip they had at various speeds. The GT2 aero package including the productions style front splitter did not require a large rear wing to produce aerodynamic balance therefore the car behaved with much more predictability at all speeds.
The previous GT1 car used carbon ceramic brake rotors and pads clamped down by AP Racing six-piston monoblock calipers on the front and four-piston in the rear. To keep costs down the GT2 regulations did not permit the use of carbon ceramic brake rotors, therefore the GT2 C6.R was equipped with slotted and grooved steel rotors. The calipers on the GT2 car remained AP Racing six piston monoblocks on the front and four piston on the rear, which both featuring ceramic composite pads.
The production ZR1 Corvette, came equipped with Brembo carbon ceramic brakes as standard that featured phenomenal stopping power with zero brake fade at the track. With the front diameter of the factory rotors being 15.5 inch (394mm) and rear diameter of 15 inch (380mm) these brakes became the largest most powerful brakes ever equipped to a factory Corvette. Doug Fehan mentioned they would have loved to used the production ZR1 brakes on the race car if the rules allowed for it. Later at a media test in 2010 Jan Magnussen ran both the GT2 C6.R and factory ZR1 around Miller Motorsports Park in Utah. Magnussen was astounded that the braking points on the track were the same between the race car and road car despite the 608 lb weight difference.
Despite the concerns of Corvette Racing switching to steel brake rotors, they did have previous experience. When the C5-R competed in the Rolex 24 at Daytona in 1999 the use of carbon ceramic brakes was illegal, therefore the team ran steel brakes for that event. The team also received data from AP Racing and input from other GM racing programs that used steel brakes. After initial testing the team was surprised with the impressive performance of the steel brakes. Doug Louth mentioned how the steel brakes did not produce the same absolute stopping power of the previous carbon brakes, however the braking performance, repeatability, consistency and driver feel met all their targets.
The suspension setup between GT1 and GT2 cars remained unchanged. The rules mandate the suspension must use production foundations but allows for aftermarket components to be used for full adjustability. The GT1 C6.R suspension was supplied by Moton with the use of Eibach springs. This suspension setup worked flawlessly on the GT1 car therefore this setup was carried across to the GT2 C6.R.
The suspension of the race car used the production ZR1 mountings however the ZR1s composite leaf spring and magnetic dampers were removed. Pratt & Miller replaced the factory suspension with short/long double wishbones with fabricated steel upper & lower control arms and machined aluminum knuckles. The setup also included multi-adjustable shock absorbers and dampers with Eibach coil over springs. The bespoke anti-roll bars was also carried across from the GT1 car.
This allowed Corvette Racing to go into the GT2 category with a small advantage due to a library of suspension setups for the different race circuits on the ALMS calendar. These setups would need adjustments due to the increase in weight and lower downforce levels of the GT2 car, but the team could build upon existing data.
The suspension of the race car was fully adjustable from damper settings such as rebound, bump including fast and slow bump settings. The spring settings could be fully adjusted to control spring rates to maximize tire contact. The ride height could be independently adjusted to reduce drag, avoid bottoming out, or create different rake angles to aid the aero balance. Finally the anti roll bars were fully adjustable allowing the team to control different levels of body roll.
The suspension along with the stiffer chassis of the ZR1 surprised the team during initial testing due to the increase in mechanical grip over the GT1 predecessor. This made up for the loss in downforce and overall created a more predictable and fun handling race car.
Corvette Racing switched to Michelin in 2004 after the performance of their previous Goodyears tires were no match to the Michelins of the rival Prodrive Ferrari at the 2003 Le Mans 24 hours. Prodrive were able to double stint their Michelins that also produced higher levels of grip. Corvette Racing were limited to changing their Goodyears at ever pitstop. After the team switched to Michelin the following year they saw a six second faster lap time at Le Mans and have never looked back since.
The Michelin Pilot radials of the GT2 car do not differ from the ones used on the GT1 version. The tire size and compound is restricted to the FIA and ACO rules with the front tire being 300/33-R18 and the rear tire size being 310/41-R18. Due to the wide tires and bespoke suspension the wheels protrude further from the chassis making for a wider axle track. This was housed under noticeable flared fenders making the GT2 car 4.7 inches (119.4mm) wider than the production ZR1 road car.
Although the tire and wheel size remains the same as the GT1 car the GT2 rules do not allow the use of the magnesium BBS wheels the GT1 car used. Pratt & Miller would continue using BBS as their wheel supplier and the six spoke with split end design carried across, however the GT2 wheel had to be constructed of aluminium. This added sprung weight to the car and added to the overall increase in weight of the GT2 car over its GT1 variant.
The GT1 rules allowed for real time telemetry, therefore the GT1 C6.R was equipped with almost 100 individual sensors that monitored anything from engine oil pressure, tire pressures and even transmission temperatures. This information was directly relayed to the pits, where a team of engineers and technicians could observe the status of car including foreseeing potential issues. The GT2 rules did not allow the use of real time telemetry, therefore during each pitstop a member of the pit crew would hook up a laptop to download the data from a connector located in the A pillar.
The ban of telemetry was decision made by the FIA to help keep costs down, however the argument for the use of real time telemetry could save money overall. This is because telemetry enables teams to catch and avoid catastrophic failures such as a blown engine, transmission seizure, or a tire blow out can cause accidents potentially causing injury.
With the team unable to monetize the telemetry in real time, it created more responsibility on the drivers to try catch minor problems before they became major. With the limited visibility, g-force and controlling a race car at high speed, the driver is far less effective at monitoring the data from within the car as technicians are in pit lane looking at their computer screens. Pratt & Miller decided to work on smarter dashboard alarm system that alerted the driver if an issue arose. This system was designed not to distract the driver under normal racing conditions allowing the driver to focus on the main task at hand.
Approximately 70% of the car remained yellow but the rear of the car was painted black, which broke across the car from the rear wheels via multiple splinters. Some of the splinters on the rear quarter panels featured a thin silver highlight. Towards the top of the car was painted black, which carried across the hood cowl and finished in the hood waterfall. The headlights bezels remained black along with the black BBS wheels. The ZR1 style front splitter was also painted black unlike the exposed carbon fiber of the production version.
The main sponsor remained Compuware and the two cars featured identical paint schemes. This resorted to the team continuing the tradition of using a red Corvette window banner, color coded yellow side mirrors and rear wing end plates for the #3 car. The #4 was separated from the sister car via the use of a black Corvette window banner, black side mirrors and rear wing end plates.
Between 2009 and 2013 Corvette Racing would debut a completely new livery each season, which was something they hadn’t done before and yet to do again since. Despite the changes in livery design, yellow always remained the primary color.
The debut of the GT2 C6.R was unlike the previous race cars of Corvette Racing. In 2008 Corvette Racing had announced that they would be building a car to compete in the GT2 ALMS category for 2009, however the car would not debut until later in the year. This would automatically break the eight consecutive ALMS Manufactures Championships as the team had decided not to fight for a championship in 2009 due to being a limited season. This decision was made due to the GT2 car would not be finished in time for the start of the 2009 season and also Corvette Racing wanted to have one last run at Le Mans in GT1.
Corvette Racing in 2004 had become rivals with Prodrive. This rivalry grew further in 2005 when both teams debuted their new cars with the Corvette C6.R from Pratt & Miller and the Aston Martin DBR9 from Prodrive. Prodrive being a British based constructor only ran a few races in the ALMS with 2006 being the only full season participation. This created the rivalry to really peak between the two teams at Le Mans. Corvette Racing won the GT1 class at the Le Mans 24 Hours in 2005 and 2006 with Prodrive winning in 2007 and 2008 making the score an even two a piece. This motivated Corvette Racing to run the GT1 C6.R at the 2009 Le Mans 24 Hours one last time to take the crown as greatest Le Mans GT1 team.
At the 2009 season opener at Sebring Corvette Racing brought back chassis C6R-007 and C6R-008 from the previous season sporting a new livery. The GT1 Championship Edition paint scheme GM introduced in 2009 for the Z06 was in celebration of the success Corvette Racing had in the GT1 category. The original plan was for the team to run just Sebring in March and Le Mans in June before the introduction of the GT2 car in August. However this plan was altered with the team running the two GT1 C6.Rs at round three of the ALMS at the Long Beach street circuit. This decision was made due to the main sponsor of Corvette Racing; Compuware being based in Long Beach, California.
Unfortunately the final Le Mans GT1 battle between Prodrive and Pratt & Miller would never happen as Prodrive decided to aim for an overall win at the 2009 Le Mans 24 Hours. This saw Prodrive build in conjunction with Lola the Aston Martin DBR1-2 B09/60 LMP1 car that finished fourth overall. This left the competition in GT1 an easy feat for Corvette Racing with the #63 car winning the GT1 class at the 2009 Le Mans 24 Hours. It was almost a perfect finish with a Corvette GT1 podium lockout but unfortunately the #64 suffered transmission failure with only a couple of hours remaining. This handed the #63 C6.R the win with a Luc Alphand Aventures C6.R following in second and the Jetalliance Aston Martin DBR9 taking final spot of the podium in third. The GT1 car was officially retired from Corvette Racing in spectacular fashion closing the GT1 chapter on a major high.
Upon their return to the USA, Corvette Racing missed two more rounds of the American Le Mans Series and came through on their promise of debuting the new GT2 car at round six of the season at Mid-Ohio. The ACO required the maximum engine displacement of a GT2 to be 5.5L, however seeming the 2009 Le Mans had passed, the organizers of the ALMS allowed Pratt & Miller to use the LS7.R from the GT1 car as long as it was reduced to a displacement of 6.0L making for an easier transition to GT2. The GT2 engine along with its smaller displacement featured smaller air restrictors to meet the 490hp power limit of the GT2 regulations.
There was a total of 10 entries in the GT2 class at Mid-Ohio with factory entries from Ferrari, Porsche and BMW. This roster included a single entry from Robertson Racing, LLC with a Ford GT they had constructed themselves to GT2 regulations named the Ford GT-R MK. 7. The other manufacturer was from the Panoz Team PTG with a single Panoz Esperante GTLM. The large roster for GT2 would become the most competition Corvette Racing had faced in years and directly correspond with their goal of displaying the potential of the Corvette brand versus the rest of the worlds best. The new GT2 C6.R immediately impressed the media and fans alike in its debut race finishing second in class behind the Flying Lizard Porsche.
The next round took place at Road America for round seven of the 2009 ALMS season. The GT2 class featured 11 entries due to the old rival of Corvette Racing, the Dodge Viper, rejoining the series ran under Primetime Race Group. Road America had been the main test track for GT2 C6.R during its development due to its combination of tight turns, elevation changes, fast kinks and long straights. Due to fast pace nature of the course it favoured the less restricted BMW M3 E92 from BMW Rahal Letterman Racing Team. Due to the saloon design of the BMW M3 in comparison to the sports car/ supercar designs of the rest of the GT2 field, the organizers had been a lot more generous to the BMW team. They had allowed BMW to have a larger splitter and rear wing that generating more downforce than the rest of the field as well as larger air restrictors to increase the power output of the motor. BMW took first and second place in GT2 with the #3 Corvette C6.R taking third.
Round eight of the ALMS series took place at Mosport International Raceway in Canada. After two hours and 45 minutes of hard battling, Corvette Racing took their first ever GT2 class win in only their third race in the category. The team were not surprised as they had all the confidence in the new GT2 car, however Ferrari, Porsche and BMW were not happy as they did not want to see a repeat of what happened in the GT1 class, where Corvette Racing chased away the competition from their shear dominance. This led to some Balance Of Performance (BOP) changes to slow the C6.R for the remainder of the 2009 ALMS season.
Round nine of the ALMS headed to Road Atlanta for the first endurance race for the GT2 C6.R at the Petit Le Mans. A total of 14 entries in the GT2 class including another Corvette built and entered by LG Motorsports and a Jaguar XKR from RSR. Corvette Racing missed the podium for the first time in GT2 and the first time in the ALMS since the Miami in 2003. The #4 C6.R took fourth in class with the #3 car taking sixth.
The season finale of the 2009 ALMS season was the four hour race at Laguna Seca. The end of the race would prove rememberable as well as controversial. Jan Magnussen in the #3 C6.R was battling for first place in class behind the #45 Flying Lizard Porsche 911 driven by Jörg Bergmeister. With only 10 minutes remaining in the race, Magnussen had closed on the rear of the class leading Porsche. Magnussen made a couple of attempts for a pass into turn one to pass Bergmeister, including an impressive moment when Magnussen went three wide whilst lapping the Ford GT-R and simultaneously attempting to overtake the Porsche. Each pass attempt by Magnussen was on the outside of turn one, which Bergmeister simply forced Magnussen off the track at the exit of the turn. Eventually a frustrated Magnussen went for an aggressive overtake on the inside of the front straight but due to Bergmeister closing the gap, Magnussen was pushed into the exit of pitlane. Magnussen decided to use the extra tarmac to complete the overtake to the delight of the crowd and the Corvette Racing crew. Magnussen immediately started to build a large gap from the Porsche, however the officials deemed the overtake illegal due to the use of pit exit, therefore Magnussen was forced to let Bergmeister pass back into the lead. With the race leading prototypes forcing an extra lap, it left Magnussen only two laps to make another attempt. This came down to the last turn on the final lap, where Magnussen bumped the rear of the Bergmeister, upsetting the balance of the Porsche. This opened a small gap for Magnussen to pull into the inside of the turn, which created a side by side drag race with the Porsche. to the finish line. The Corvette was slightly edging ahead of the Porsche when Bergmeister decided to turned into the side of Corvette, making heavy contact. Bergmeister persisted to bang the side of the Corvette forcing Magnussen up against the pitwall and as Magnussen had almost completed the pass, Bergmeister braked and turned hard into the right rear of the Corvette forcing Magnussen into a spin. Magnussen was a passenger as his Corvette was forced into head on collision with the opposite side wall. The Corvette hit hard only a few feet before the finish line as the Porsche passed by in the background taking the victory. The C6.R slid across the finish line in second place and was heavily damaged and despite the dangerous driving of Jörg Bergmeister, the result stood giving Flying Lizard Motorsports the GT2 class win. Magnussen sustained a broken tailbone in the accident, which lead to Pratt & Miller redesigning the seat in that area to avoid a future injury. The injury was fairly minor due to the car registering an impact of 50G, which displayed the integrity of the safety features of the C6.R.
Overall the debut of the GT2 C6.R proved to be a successful one as the car demonstrated a lot of pace, accomplishing four podiums in five races. Corvette Racing and Pratt & Miller had yet again built a phenomenal GT race car, beating the best the rest of the world had to offer.
Chassis C6 RGT-001
The first GT2/GT specification Corvette race car built by Pratt & Miller for Corvette Racing. During the 2008 season Corvette Racing announced they would be building a race car to compete in the GT2 class for the upcoming American Le Mans Season. The perfect storm of the global financial crisis and the demise of competition created the elimination of the GT1 class. The more cost effective GT2 class became the popular choice for a lot of big car manufacturers.
Pratt & Miller had to construct a completely new car for the GT2 regulations. The GT2 rulebook mandated a much higher use of production based components including the complete factory chassis and floor plan. Pratt & Miller would test the three available bodies and two different frames of the production Corvette models available at the time, but in the end the data favouring the new ZR1 Corvette setup.
The stiffer and lighter aluminum hydroformed frame of the ZR1 became the backbone of the car, which overall supplied a much higher level of mechanical grip. Many changes had to be made from the previous GT1 car, including a whole new body, using the production ZR1 panels featuring large fender flares for the wider axle track. The aero package was much smaller than the previous GT1 car therefore Pratt & Miller would capitalized on the unique aero design of the production ZR1. The overall downforce levels of the GT2 aero was much lower, however the increase in mechanical grip and more predictable handling was greatly received by the drivers.
Due to the short timeframe and limited budget the C6.R GT2 was built upon, the ALMS allowed for Pratt & Miller to use a detuned version of the LS7.R from the previous GT1 car. With a shorter crankshaft stroke, the displacement was reduced form 7.0L to 6.0L and to bring the power output down from the original 590 hp, smaller air restrictors were added as the decrease in displacement wasn’t enough to meet the 490 hp limit of the GT2 class. The LS7.R was only used in the GT2 C6.R for 2009 as the team switched to GM in-house operation with a 5.5L engine built to meet the FIA and ACO regulations.
The GT2 rules did not allow the use of the carbon ceramic brake rotors, therefore Pratt & Miller had to switch to steel rotors. Due to other GM racing platforms and data from AP Racing, Corvette Racing were able to make an easy transition to the steel brakes. After initial testing the team and were impressed with the overall performance of the steel brake rotors.
The GT2 C6.R had an impressive debut in 2009, with chassis C6 RGT-001 finishing second in class in its debut race, third in class in its second race and collecting the first GT2 class win for Corvette Racing in only its third race.
C6 RGT-001 was involved in a heavy crash at the finish line at the 2009 season finale at Laguna Seca. Jörg Bergmeister in the Flying Lizard Porsche spun out Jan Magnussen in the Corvette at the finish line handing the class win to Flying Lizard with the Corvette crossing the finish line second in class after a head on collision with the wall.
C6 RGT-001 was used for the full 2010 season, which underwent a few changes. Due to the elimination of the GT1 class the American Le Mans Series decided to rename the GT2 class to GT. For FIA and ACO events such as Le Mans the class remained GT2 upto 2011 when it was renamed to GTE. The aero package of the car was slightly altered in 2010 with a redesigned side skirts that featured a new exhaust outlet that pointed at a slight downward angle. The new exhaust helped create a minor increase in downforce due to the flow of the gases. The front fenders incorporated a cut out in the lower rear section that allowed for a better extraction of turbulent air created by the rotation of the wheels at high speed. The turbulent air created front end lift, which was previously extracted via fender louvers on the GT1 car but due to the GT class rules enforcing the use of production fenders, it ended the use of fender louvers.
2010 saw the introduction of the in-house GM built race engine. Corvette Racing had used a Katech developed engine since the inception in 1999 with an almost flawless record. To help lower the overall costs of the Corvette Racing team, GM decided to build their own race engines, which incorporated the 5.5L displacement limit for the GT class rules. The new engine dubbed the LS5.5-R took lessons learnt from GMs partnership with Katech, however at the 2010 Le Mans 24 Hours, both engines suffered catastrophic failure. This would become the first full team retirement for Corvette Racing at the legendary race.
Corvette Racing set big goals for the GT2 car in 2010, but unfortunately under the new GT2/GT regulations and the strict Balance of Performance limitations, Corvette Racing ended the 2010 season with their worst performance at the time with C6 RGT-001 accomplished only two podiums.
C6 RGT-001 was sold to the French team of Larbre Competition at the end of 2010. At the hands of Larbre Competition, C6 RGT-001 accomplished the 2011 ILMC GTE Am Championship, the GTE Am class win at the Le Mans 24 Hours in 2011 and 2012, and the FIA WEC GTE Am team Championship in 2012.
The sister car of C6 RGT-001 featuring an identical setup, also made its debut at round six of the ALMS at Mid-Ohio. C6 RGT-002 accomplished its first class podium in its third race at Mosport, where the sister car accomplished the first GT2 class win for Corvette Racing.
In the 2010 season C6 RGT-002 had more success than the sister car accomplishing four class podiums and one class win. The team’s only win came at the 2010 Petit Le Mans when the class leading #62 Risi Competizione Ferrari ran out of fuel on the final lap handing Corvette Racing the GT2 class win.
The team had set major goals for year with Gary Pratt aiming for the 2010 ALMS GT class championship and the GT2 class win at the 2010 Le Mans 24 Hours. Despite the better results of C6 RGT-002 the 2010 season would go down at the time as the worst full season for Corvette Racing.
The 2010 cars featured a new livery with a primarily Velocity Yellow front with the rear portion of the car painted black. The black was separated from the yellow via a silver razor wire style design that started at the front lower portion of the sideskirts and finished around the rear Corvette emblem. Due to both C6.Rs using identical liveries the tradition of the #4 car using a black Corvette window banner with black side mirrors and rear wing endplates continued. The #3 car used a red Corvette window banner with yellow side mirrors and rear wing end plates.
For the 2010 season both C6 RGT-001 and C6 RGT-002 switched from using E85 Ethanol flex fuel to VP Racing fuel.
After the 2010 season with Corvette Racing, C6 RGT-002 was sold to Selleslagh Racing Team (SRT). Under SRT, C6 RGT-002 competed in the 2014 International GT Open where it accomplished seven wins and later in the 2016 Blancpain GT Series where it took back to back, third place finishes.
C6GT-003 made its debut at the 59th Annual Mobil 1 Twelve Hours of Sebring on the 19th of March 2011. After 2010 saw Corvette Racing produce their least competitive season, Pratt & Miller had incorporated more changes to the GT spec C6.R.
For 2011 the FIA allowed the use of paddle operated transmissions in the GT/GTE class therefore in late 2010 Pratt & Miller tested the new transmission at Road Atlanta. The paddle operated Xtrac six-speed transmission required Pratt & Miller to tune the electronics of the C6.R to allow for accurate spark and fuel cut as well as speed matching downshifting. The use of the paddle shifters was not mandatory in the GT/GTE class but was popular due the increase in performance due to faster gear changes along with added benefit of less wear and tear on the drivetrain.
Along with the new transmission the aero package saw an upgrade on C6GT-003. The rules had allowed for a slight increase in the angle of the rear diffuser, which Pratt & Miller immediately capitalized on. C6GT-003 saw new cut outs behind the rear wheels similar to the ones found on the front fenders. The angle of the redesigned diffuser was steeper creating a greater use of the Bernoulli effect, which forces the high pressure air to increase in speed towards the low pressure air. The steeper angle of the rear diffuser along with the rear wheel lower cutouts allowed for a cleaner air flow under the car, overall increasing the rear grip.
The 2011 upgrades made the C6.R more competitive, C6GT-003 accomplished two podiums in 2011 with a third place in class at the 12 Hours of Sebring and the GTE Pro class win at the 24 Hours Le Mans. The win at Le Mans was a big accomplishment for the team, especially after the double retirement the previous year. This was the first win for Corvette Racing at Le Mans outside the GTS/GT1 class.
C6GT-003 was sold to Larbre Competition at the end of 2011. Larbre Competition competed in the Intercontinental Le Mans Cup ran by the ACO. In 2011 the ACO renamed the GT2 class to GT Endurance (GTE), which was separated into two subclasses named GTE Pro and GTE Am. The Pro (Professional) class was for factory teams using a full professional driver roster. The Am (Amateur) class was designed to help encourage lower cost endurance racing. This class was exclusively for privateer teams with a driver roster only allowing the use of one professional driver with strict seat time. This was to ensure the professional driver was not used primarily over the amateur drivers. The GTE Am class requires that teams use ex-factory GT race cars that were at least one year old. Under Larbre Competition C6GT-003 accomplished the GTE Am class win at the 2012 Le Mans 24 Hours, first in class at the Six Hours of Fuji and first in class at the Six Hours of Shanghai.
The Intercontinental Le Mans Cup was rebranded as the World Endurance Championship (WEC) in 2013. Larbre Competition used C6GT-003 in the 2013 WEC where it accomplished back to back podiums in the GTE Am class at the first two rounds of the season.
C6GT-004 was the sister car to C6GT-003 featuring an identical setup that debuted on March 19th 2011 at the Twelve Hours. of Sebring. During the 2011 ALMS season C6GT-004 produced better results than the sister car by accomplishing four podiums including a class win at Mosport. The success of C6GT-004 put Corvette Racing as runner up in the ALMS GT Manufacturers Championship behind BMW Team RLL. Oliver Gavin and Jan Magnussen would finish second in the GT Drivers Championship standings behind Joey Hand and Dirk Müller of BMW Team RLL.
Both C6.Rs featured a new livery for the 2011 season. Velocity Yellow remained the primary color with the rear of the car painted black. The black paint featured horizontal blades with silver shards incorporated into it. The #3 and #4 car featured identical liveries so the traditional separation continued in 2011 with the #3 car using a red Corvette window banner with yellow side mirrors and rear wing end plates. The #4 car in contrast used a black Corvette window banner with black side mirrors and rear wing end plates.
The mandatory air conditioner was further adapted in 2011, becoming more effective as well as efficient. The compressor of the A/C unit was powered by a jackshaft off the transaxle. This setup only cost three horsepower, a very low loss of power compared to traditional air conditioners found in cars.
The 2011 ALMS regulations required every car to be equipped with a mandatory roof camera, which also slightly altered the appearance of the 2011 car over its predecessors.
C6GT-005 was one of the last GT spec C6.R Corvettes built. It was used for two seasons with Corvette Racing before the introduction of the seventh generation Corvette race car dubbed the C7.R in 2014.
The rules in 2012 for the GT class had changed, allowing teams to increase the overall width of the cars and adapt the aero package. Pratt & Miller unhappy with the results over the last two seasons wasted no time making improvements to the C6.R to ensure C6GT-005 and C6GT-006 was ready for their debut on March 17th 2012 at Sebring International Raceway.
Corvette Racing’s competitor, Risi Competizione, introduced the Ferrari 458 Italia GT2 to the ALMS in 2011, which featured a wider axle track over the rest of the grid. This caused the organizers to allow the rest of the GT roster to increase the width of their cars by 50mm (1.969 Inches) to eliminate any advantages the Ferrari may have. To meet the 50mm increase in width Pratt & Miller had to extend the front control arms and increase the rear wheels offset.
During the off-season Pratt & Miller worked very closely with Michelin to develop a better tire package for the upcoming 2012 season. Michelin optimized their tires for the new chassis configuration due to the wider car transferring less load under cornering. The setup created more lateral capacity and involved CFD analysis, surface optimization and wind tunnel testing. The longer front control arms produced different loads that required Pratt & Miller to look at new fatigue calculations, leading to durability testing, and packaging studies.
To accommodate the wider track of C6GT-005, the fender flares were increased giving the car a more muscular appearance over the previous model. Pratt & Miller had visited the wind tunnel in Charlotte leading to an improved aero package. The 2012 rule changes allowed for an increase in height of the rear wing, therefore C6GT-005 mounted its rear wing 75mm (2.9 inches) higher than the wing used the previous year. The higher location of the rear wing helped increase the rear downforce but in conjunction removed pressure from the front axle. To balance the aero package Pratt & Miller added canards/dive planes to the front fascia along with a larger front splitter. The lower fender cutouts located behind the front wheels were redesigned due to the 2 inch wider fender flares. These cutouts were made deeper and merged into the redesigned rocker panels and side skirts to help control air flow. Due to the new design of the rocker panels the side exit exhausts was redesigned, which helped create a better control of side force air flow. The lower rear wheel cutouts almost doubled in size over the previous year, aiding more airflow to the rear diffuser. To complete the new aero package, the side mirrors featured a new bespoke Pratt & Miller design. The previous Pratt & Miller Corvette race cars had simply used the factory Corvette side mirrors with minor modifications such as a drilled hole for cabin air flow. For C6GT-005 the side mirrors featured a slim long neck from its mounting on the door and incorporated a steeper angle. The location of the actual mirror was closer to the driver increasing the visibility over the previous mirrors that saw a small obstruction by a section of the roll cage.
The engineers at the Wixom Performance Build Center made improvements to the LS5.5-R engine. With a power increasement, improvement in driveability, better throttle response and fuel economy all derived by a new intake manifold. The 2012 GT regulations allowed the twin 28.6mm air intakes to be increased to 29.2mm, which also created a bump in performance. Finally the calibration of the paddle operated transmission was revised to improve its overall functionality allowing for better durability.
C6GT-005 during the 2012 ALMS season accomplished five podiums and was far more competitive than the previous GT spec C6.Rs. The success of the C6GT-005 landed Corvette Racing their first ALMS GT Manufactures Championship. This would add to a ninth manufactures championship overall for the team. C6GT-005 was also used for the 2013 season, which became the last season for the sixth generation Corvette under Corvette Racing. In the 2013 season, C6GT-005 accomplished five podiums, including class wins at Laguna Seca, Baltimore and the Circuit of the Americas at Austin, Texas. These wins captured C6GT-005 the 2013 ALMS Drivers Championship for Jan Magnussen and Antonio Garcia. The success of C6GT-005 during the 2013 season handed Corvette Racing their second consecutive ALMS GT Manufactures Championship adding to a total of 10 manufacture championships for Corvette Racing.
C6GT-006 was the final sixth generation Corvette race car built by Pratt & Miller for Corvette Racing. It was the sister car to C6GT-005 and featured an identical setup. C6GT-006 made its debut on March 17th 2012 at the Twelve Hours of Sebring. C6GT-006 like the sister car was used for two seasons by Corvette Racing between 2012 and 2013.
Due to the GT regulation changes in 2012, C6GT-006 featured the same upgrades as the sister car. During initial testing, Oliver Gavin reported the changes made to the new car along with the wider track improved the overall balance. He compared the improvements of the 2012 car to the handling of the previous GT1 C6.R. He was amazed by the work done by the team of engineers to improve the aerodynamic development and technology of the 2012 car.
During the 2012 ALMS season, C6GT-006 accomplished seven GT class podiums including four GT class wins. The success of C6GT-006 led Oliver Gavin and Tommy Milner to the 2012 ALMS GT Drivers Championship, which handed Corvette Racing their first ALMS GT Manufactures Championship. This would be Corvette Racing’s first championship after a two year drought and became their ninth manufactures championship overall.
During the 2013 ALMS season C6GT-006 accomplished three GT class podiums including wins at the 12 Hours of Sebring and Mosport. The win at Sebring became the sole GT class victory for Corvette Racing at the 12 Hours of Sebring since they transitioned from GT1.
C6GT-006 along with the sister car used two liveries between 2012 and 2013. The 2012 livery was predominantly Velocity Yellow with a black tribal design that started from the rear and tapered down the sides towards the front. Incorporated into the black tribal pattern between the door and quarter panel was the ‘Jake Skull’ featuring silver colored eyes/flags.
For the 2013 livery, Velocity Yellow remained the primary color but the black tribal design featured a cleaner look and silver accents. 2013 was the 60th anniversary for the Corvette brand, therefore the race livery featured a new look to celebrate the milestone. This celebration paint scheme replaced the ‘Jake Skull’ from the 2012 livery with the Corvette 60th anniversary logo. This logo was made up of a black and yellow C6 Corvette emblem decal with the number 60 above it. For both the 2012 and 2013 seasons the two cars were separated by the tradition of the #3 car using a red Corvette window banner with yellow side mirrors and rear wing end plates and in contrast the #4 car used a black Corvette window banner with black side mirrors and rear wing end plates.
At the end of the 2013 season, C6GT-006 was sold to Selleslagh Racing Team (SRT) where it competed in the 2014 International GT Open season. During the 2014 season, C6GT-006 collected nine podiums including race wins at the Nürburgring, Algarve, and Spa Francorchamps.
In 2015 Selleslagh Racing Team (SRT) prepared C6GT-006 for their affiliate team, V8 Racing, for the 24H Series powered by Hankook. C6GT-006 competed in the 24H Series between 2015 and 2019.
|Model:||Chevrolet Corvette C6.R ZR1|
|Body Style:||Two-door coupe hatchback|
|Layout:||Front engine, longitudinal powertrain placement|
|Driveline:||Rear wheel drive|
|Steering:||Power-assisted rack and pinion|
|Steering Column:||Production Corvette with tilt|
|Rear View Display:||Intel|
|Headlights:||Hella 15 Volts|
|Safety Equipment:||Willans six-point harness, drivers side crash box, window net, roll cage|
|Manufacturing Location:||Pratt & Miller, New Hudson, Michigan, USA|
|Displacement (cu in / cc):||366.1 / 6000||335.2 / 5493||335.2 / 5493|
|Engine V-angle:||90° cylinder angle||90° cylinder angle||90° cylinder angle|
|Valvetrain:||16-valve, pushrod with overhead titanium valves, two valves per cylinder||16-valve, pushrod with overhead titanium valves, two valves per cylinder||16-valve, pushrod with overhead titanium valves, two valves per cylinder|
|Air Intake Restrictor Size (mm / In):||28.6 / 1.125||28.8 / 1.134||29.2 / 1.15|
|Bore (mm / In):||106.2 / 4.18||103.89 / 4.090||103.89 / 4.090|
|Stroke (mm / In):||84.33 / 3.32||80.90 / 3.185||80.90 / 3.185|
|Cylinder Case Material:||Aluminum||Aluminum||Aluminum|
|Cylinder Head Material:||Aluminum, CNC Ported||Aluminum, CNC Ported||Aluminum, CNC Ported|
|Throttle Systems:||Individual runners with carbon fiber proprietary butterflies||Individual runners with carbon fiber proprietary butterflies||Individual runners with carbon fiber proprietary butterflies|
|Fuel:||E85R||VP Racing Fuel||VP Racing Fuel|
|Fuel Delivery:||Kinser sequential multi-point electronic indirect fuel injection||Kinser sequential multi-point electronic indirect fuel injection||Kinser sequential multi-point electronic indirect fuel injection|
|Lubrication:||Mobil 1, Dry Sump||Mobil 1, Dry Sump||Mobil 1, Dry Sump|
|Horsepower (hp / kW @rpm):||470 / 350.5 @ 4800 rpm||485 / 361.6 @ 6000 rpm||491 / 366.1 @ 5800 rpm|
|Torque (lb ft / Nm @ rpm):||535 / 725 @ 4500 rpm||479 / 649 @ 4500 rpm||485 / 657 @ 4800 rpm|
|Transmission:||Xtrac 6-speed sequential||Xtrac 6-speed sequential||Xtrac 6-speed sequential|
|Clutch:||AP Racing Multi-plate carbon fiber||AP Racing Multi-plate carbon fiber||AP Racing Multi-plate carbon fiber|
|Differential:||AP Racing adjustable mechanical limited-slip differential||AP Racing adjustable mechanical limited-slip differential||AP Racing adjustable mechanical limited-slip differential|
|Front:||Moton independent, short/long double wishbone, fabricated steel upper & lower control arms, machined aluminum knuckles, coil-over multi-adjustable shock absorbers, anti-roll bar|
|Rear:||Moton independent, short/long double wishbone, fabricated steel upper & lower control arms, machined aluminum knuckles, coil-over multi-adjustable shock absorbers, anti-roll bar|
|Shock Absorber Kits:||Moton|
|Front Rotors (in / mm):||Steel vented and slotted (15.35 / 389.9)|
|Rear Rotors (in / mm):||Steel vented and slotted (14.0 / 355.6)|
|Front Calipers:||AP Racing six-piston monoblock with composite pads|
|Rear Calipers:||AP Racing four-piston monoblock with composite pads|
|Brake Fluid:||Mobil 1 DOT 4|
|Tire:||Michelin Pilot Radial|
|Tire Compound:||Soft, Medium, Hard and Grooved Wet|
|Wheels:||BBS aluminum, single center locking wheel nut|
|Front wheel size (Inches):||12.5 x 18|
|Rear wheel size (Inches):||13 x 18|
|Front tire size:||300 / 32 – R18|
|Rear wheel size:||310 / 41 – R18|
|Wheelbase (in / mm):||105.7 / 2684.8||105.7 / 2684.8||105.7 / 2684.8|
|Overall length (in / mm):||176.2 / 4475.5||176.2 / 4475.5||176.2 / 4475.5|
|Overall width (in / mm):||78.6 / 1996.4||78.6 / 1996.4||80.1 / 2034.5|
|Overall height (in / mm):||45.9 / 1165.9||45.9 / 1165.9||45.9 / 1165.9|
|Weight (pounds / kg):||2745 / 1245||2745 / 1245||2745 / 1245|
|Fuel Capacity (gal / liter):||29 / 131.8||26.4 / 120||26.4 / 120|
|Wing Chord (in / mm):||11.81 / 300||11.81 / 300||11.81 / 300|
|Splitter (in / mm):||1.0 / 25||1.0 / 25||1.0 / 25|
GT1 C6.R vs GT2 C6.R & GT C6.R
|2009 C6.R GT1||2009 C6.R GT2||2012 C6.R GT|
|Model:||Chevrolet Corvette C6.R GT1||Chevrolet Corvette C6.R GT2||Chevrolet Corvette C6.R ZR1|
|Homologation Model:||Chevrolet Corvette Z06||Chevrolet Corvette ZR1||Chevrolet Corvette ZR1|
|Chassis:||Hydroformed Steel||Hydroformed Aluminum||Hydroformed Aluminum|
|Engine:||Katech LS7.R||Same||GM LS5.5-R|
|Displacement (cu in / cc):||427 / 6997||366.1 / 6000 (-60.9 / -997)||335.2 / 5493 (-91.8 / -1504)|
|Engine V-angle:||90° cylinder angle||Same||Same|
|Valvetrain:||16-valve, pushrod with overhead titanium valves, two valves per cylinder||Same||Same|
|Air Intake Restrictor Size (mm / In):||30.6 / 1.2||28.6 / 1.125 (-2.0 / -0.075)||29.2 / 1.15 (-1.4 / -0.05)|
|Bore (mm / In):||106.2 / 4.18||106.2 / 4.18||103.89 / 4.090 (-2.31 / -0.09)|
|Stroke (mm / In):||98.42 / 3.875||84.33 / 3.32 (-14.09 / -0.555)||80.90 / 3.185 (-17.52 / -0.69)|
|Cylinder Case Material:||Aluminum||Same||Same|
|Cylinder Head Materiel:||Aluminum, CNC Ported||Same||Same|
|Throttle Systems:||Individual runners with carbon fiber proprietary butterflies||Same||Same|
|Fuel:||E85R||Same||VP Racing Fuel|
|Fuel Delivery:||Kinser sequential multi-point electronic indirect fuel injection||Same||Same|
|Lubrication:||Mobil 1, Dry Sump||Same||Same|
|Horsepower (hp / kW @rpm):||590 / 440 @ 5400 rpm||470 / 350.5 @ 4800 rpm (-120 / -89.5)||491 / 366.1 @ 5800 rpm (-99 / -73.9)|
|Torque (lb ft / Nm @ rpm):||640 / 868 @ 4600 rpm||535 / 725 @ 4500 rpm (-105 / -143)||485 / 657 @ 4800 rpm (-155 / -211)|
|Transmission:||Xtrac 6-speed sequential||Same||Xtrac paddle operated 6-speed sequential|
|Front Suspension:||Moton independent, short/long double wishbone, fabricated steel upper & lower control arms, machined aluminum knuckles, coil-over multi-adjustable shock absorbers, anti-roll bar||Same||Same|
|Front Brake Rotors (in / mm):||Hitco carbon ceramic (14.9 / 380)||Steel vented and slotted (15.35 / 389.9)||Steel vented and slotted (15.35 / 389.9)|
|Rear Brake Rotors (in / mm):||Hitco carbon ceramic (13.97 x 1.25 / 355 x 32)||Steel vented and slotted (14.0 / 355.6)||Steel vented and slotted (14.0 / 355.6)|
|Front Calipers:||AP Racing six-piston monoblock||AP Racing six-piston monoblock with composite pads||AP Racing six-piston monoblock with composite pads|
|Rear Calipers:||AP Racing four-piston monoblock||AP Racing four-piston monoblock with composite pads||AP Racing four-piston monoblock with composite pads|
|Wheels:||BBS forged magnesium, single center locking wheel nut||BBS aluminum, single center locking wheel nut||BBS aluminum, single center locking wheel nut|
|Front wheel size (Inches):||12.5 x 18||Same||Same|
|Rear wheel size (Inches):||13 x 18||Same||Same|
|Front tire size:||290 / 33 – R18||300 / 32 – R18||300 / 32 – R18|
|Rear wheel size:||310 / 41 – R18||Same||Same|
|Wheelbase (in / mm):||105.7 / 2684.8||Same||Same|
|Overall length (in / mm):||177.6 / 4511||176.2 / 4475.5 (-0.4 / -36)||176.2 / 4475.5 (-0.4 / -36)|
|Overall width (in / mm):||78.7 / 1999||78.6 / 1996.4 (-0.1 / -2.6)||80.6 / 2047.24 (+1.9/ +48.24)|
|Overall height (in / mm):||45.8 / 1163||45.9 / 1165.9 (+0.1 / +2.9)||45.9 / 1165.9 (+0.1 / +2.9)|
|Weight (pounds / kg):||2425 / 1100||2745 / 1245 (+320 / +145)||2745 / 1245 (+320 / +145)|
|Wing Chord (in / mm):||15.74 / 400||11.81 / 300 (-3.93 / -100)||11.81 / 300 (-3.93 / -100)|
|Splitter (in / mm):||3.15 / 80||1.0 / 25 (-2.15 / -55)||1.0 / 25 (-2.15 / -55)|
|Canards / Diveplanes:||None||None||Yes|
|Diffuser:||Leading edge at rear axle centerline, with sideplates and longitudinal fences||Leading edge at rear most point of wheel opening, no side plates or fences||Leading edge at rear most point of wheel opening, no side plates or fences|
|Windshield:||Polycarbonate||Production Laminated Glass||Production Laminated Glass|