Risi's Petit LeMans inside track
It’s the race that Risi Competizione wants most. It has class victories at the Mobil 1 Twelve Hours of Sebring and the 24 Hours of Le Mans to its credit. All that’s left in endurance racing’s “Triple Crown” is a triumph at Petit Le Mans powered by the Totally New MAZDA6. As he has all season, Risi technical director Rick Mayer gives his insight on what it will take for Risi’s two Ferrari F430 GTs to be successful in the American Le Mans Series.
The Road Atlanta repave of last spring has had time to age. This usually increases the grip as some of the petroleum leaches out from the track. We should see a further decrease in lap times from last year’s quick times. If the weather is good, all the lap records should fall.
The track may have changed a bit but the requirements to go fast here are still the same. You need a good platform for the high-speed corners (T1, The Esses, T12). You can gain a significant amount of time using the apex curbs effectively at T3 and the exit curbs of T5. The curbs at T7 and T10 also yield lower lap times. If you don’t set up right, using the curbs will kill the drive shafts; it’s such a long race. Top speed is also key here; the top speed is just above 160 mpg for a GT2 car, a little higher for the Panoz, Corvette, Aston Martin and the Ford GT-R due to their restrictor rules break.
Stiffer (springs and anti-roll bars) is better for platform support but curbing is so important here that it’s a compromise. A stiff setup also makes cleaning the pick-up off the tires easier as you can load the tires harder. Dampers that give support but blow off on the curbs can make a big difference here, not just in lap time but longevity of drivetrain components. But you need them to blow off and not lose platform support on transitions, turn-in and braking; there are always compromises.
Top speed and downforce level will be based on peer group straight speeds. Moreover, all downforce is the quicker way around the track but you can’t get beat on the straight. Passing will be difficult, especially with a 40-car field. The best spot for passing is the braking section going into T10; if you can’t keep up on the straight you won’t be in position for outbraking into T10. The track isn’t particularly hard on brakes, but you need the brakes to last the 340-plus laps that the GT2 cars will run in the race.
This race has always been a lap race; even though there’s a time limit, the count is 394 for the overall leader which is 1,000 miles or a little less than 900 miles for the lead GT2 car. This makes pit strategy a bit different as it’s not the GT2 lap count that determines when the race ends but the pace of the overall leader.
Qualifying isn’t as important at the long races. Keeping up in the lead pack is always important. If you’re up front there’s a higher chance of getting the leader between you and the field behind you on a full course yellow, which can give you a lap up on the field. More importantly, you won’t go down a lap.
Passing and traffic will play a bigger role this year, especially in GT2. Several GT2s got restrictor breaks this season giving them more HP and the associated higher top speed. But these cars will still be slower in the corners and have slower lap times which make passing them important and difficult. The drivers will have their work cut out for them, with the track being quicker and the LMPs more aggressive (and a larger LMP field), keeping out of trouble will be more difficult than past years.
In the past, the Ferrari could double stint tires here which saved pit time. Pick-up is always an issue here; it takes several laps to clean the tires up once you’re forced off line or after a yellow, and with a 40-car field it will be hard not to go off line. The best strategy is probably to double stint on green stops but change tires on the full course yellow stops to avoid the pick-up on the restart.
We were fast here the last two years but were unable to convert this speed to a win. Let’s hope our luck changes this year.
Petit Le Mans powered by the Totally New MAZDA6 is the 10th round of the 2008 American Le Mans Series. The 1,000-mile/10-hour race is scheduled for 11:15 a.m. Saturday, October 4 from Road Atlanta in Braselton, Ga. SPEED will televise the race live with XM Satellite Radio airing live race coverage throughout the day on Channel 166. Live coverage from American Le Mans Radio will be available at americanlemans.com, which also will feature IMSA’s Live Timing & Scoring.