The American Le Mans series pitched its tent alongside the Champ Car contingent earlier this year to participate for the first time in the annual star-studded bacchanal that is the Long Beach Grand Prix. This year's grand marshals included filmmaker George Lucas and Playboy impresario Hugh Hefner, but the unofficial stars were alcohol and the merriment it invariably induces.
Toyota, the lead sponsor of the race, has long understood the PR value in having its name associated with Southern California's largest sporting event. (Attendance this year topped 175,000 on each of the race's three days.) By joining in the fun for '07, the ALMS hoped to garner more of the public exposure it needs to build its own series.
The LBGP started in 1975 as a Formula 5000 race, served as the West Coast home of the Formula 1 series from 1976-1983, and, since 1984, has played host to the Indy Car/CART/CHAMP car series. The race is played out on 1.968 miles of surface streets in downtown Long Beach. For 2007, the LBGP enticed 25 ALMS entries to test their mettle on the tricky road course.
Unfortunately, the ALMS teams were afforded precious little time to get acquainted with the unique problems posed by the street circuit. Setup was scheduled for the Thursday before the race, with no track time allotted. Friday provided a 40-minute practice in the morning and a 40-minute qualifying session in the afternoon, splitting the entries into two groups given 20 minutes each to make their best time for grid position. That left only a 20-minute warm-up Saturday morning, with the 100-minute race scheduled for 4:00 in the afternoon.
Severe wind conditions, coupled with an ever-shifting layer of dirt and sand that had blown onto the track surface Friday, made for tricky handling at race time. Getting even slightly off-line produced severe understeer, and the teams were forced to scramble to stay abreast of the changing conditions.
Nonetheless, the race got off to a clean start, and all escaped the opening Turn 1 melee that typifies Long Beach. There is a huge straight before this turn, and speeds are at a maximum coming in. It is not uncommon for one or more racers to overestimate their cars' stopping ability in an attempt to establish an early lead.
Corvette Racing had no competition in its class at Long Beach, as the lone Aston team from Sebring decided to sit out the series and wait for Le Mans. Aston Martin itself had recently been sold to a Dubai-based group fronted by David Richards of Britain's Prodrive. (As of this writing, the new company had just taken over full control of the automaker, prompting speculation that the factory-backed DBR9s would rejoin the ALMS series full time at some point after June's 24 Hours of Le Mans.)
Lacking GT1 competition, Corvette Racing team members used the LBGP to hone their driving, pit-stop, and car-prep skills in preparation for Le Mans. But with the Long Beach course offering no runoff, and hard concrete walls standing sentinel at the track's edge, drivers were forced to play the difficult game of pushing the cars to their limits-without surpassing them. Having to replace a fully-developed C6.R so soon before Le Mans could have spelled disaster.
Within 30 minutes of the start, there was an accident that brought out a long, full-course yellow. Many of the teams embroiled in battles for prominence within their respective classes were forced to make pit-stop decisions and strategy adjustments. Corvette Racing, with its focus on team development, rather than blistering race times, kept its drivers out to complete their planned full stints behind the wheel.
The race eventually completed its required time allotment in uneventful fashion. The final standings found the P2 Porsches of Penske racing dealing the dominant, diesel-powered P1 Audi R10s their first overall defeat. Corvette Racing, meanwhile, grabbed uncontested First and Second Places in class.
With Long Beach in the books, Corvette Racing looked forward to two more "tune-up" races-Houston and Salt Lake-leading up to the 24 Hours of Le Mans. Given the heavy Aston presence expected in Sarthe, the C6.R contingent would need to make the most of both of them.
Evolution of the Species
Thanks to the C6.Rs' brilliant performance in last year's ALMS series, this year's cars are largely carry-overs in the mechanical sense. Some rule changes have been enacted for the new season, however, forcing the Corvette Racing team to respond accordingly.
For 2007, ALMS regulations require that the gasoline used in competition be laced with 10 percent ethanol. The change required the GM Powertrain staff at Katech, under the direction of Roger Allen, to reach back into their computers and come up with an alternate mapping plan for the C6.R's engine-management system. According to GM engineers, if series officials decide to increase the ethanol content-to, say, 15 percent-an extensive (and costly) engine-hardware makeover will be required. Fortunately for the team, there appear to be no plans to proceed in that direction.
The other effect of the ethanol mandate is that power output has increased, as compared with the '06 fuel prescription. The tradeoff is an accompanying decrease in fuel mileage, an important factor in endurance racing. By spending untold hours in the computer lab prior to the season, GM engineers were able to achieve an operating envelope similar to that of last year's configuration, despite the fueling changes.
Another big factor in engine function and output this year is the use of a 5mm-larger air intake. The Automobile Club de l'Ouest (ACO), the sanctioning body for the European Le Mans series, is attempting to improve driver conditions by offering the larger intake size to teams running closed cars equipped with full (not suit- or helmet-contained) air-conditioning systems. The larger air-intake aperture should more than make up for any performance degradation caused by the additional weight of the A/C system and the increased load of powering an auxiliary system.
The C6.R's A/C system was designed by the GM HVAC group at Corvette Engineering, utilizing hardware virtually identical to that used in the third-row seating area of the Cadillac SRX sport-utility vehicle. The compressor and ducting systems are basically off-the-shelf parts from the GM parts bin. Fresh air is picked up from a filtered duct in the right-hand door, then sent through a finned condenser mounted in the tail of the car and into the passenger compartment.
The drivers receive cold air in several ways. There is a cabin outlet, just like in the SRX, mounted at shoulder height to the right of the driver. Air is also fed to the driver's helmet and to his back by additional ducting. All of these ducted outlets are augmented with their own fans, which force the air through the system. The system's compressor is mounted in the tail section and powered by the transaxle in tandem with the alternator.
As you might imagine, one of the potential problems with an A/C system is that the car's cabin essentially must be sealed in order to maximize the effect of the cool-air input. Because of this, a system failure is likely to be murderous on the drivers. After all, the only thing worse than driving in high-heat conditions is doing so in a closed up car with no flow-through air.
While the engineers are still working out the bugs that are inherent to any new system, the improvements in cabin comfort are already being felt and appreciated by the drivers. It's yet another way Corvette Racing is further refining the already formidable C6.R.