GRAND AM DP
to strive for, and ranges of downforce and drag to provide for its teams. ‘We did a lot of work ahead of time and a lot of analysis working towards targets around where the current cars are at,’ explained Louth. ‘That was surprisingly effective considering the new cars are night and day different to last year’s cars.’
The nose shape of the Corvette bodywork caused a few headaches for Dallara who previously used a front-mounted ‘snout-like’ radiator
COMPETITIVE BALANCE With the Corvette DP body ready for testing and tuning, the series scheduled three 12-hour shifts at Windshear’s full-scale facility in North Carolina, and multiple tests at Daytona International
“GM looks
likely to have the next
generation
body market to itself for 2012”
Teams took delivery of the DPG3 Corvettes ahead of the open test at Daytona in February. Performance on track was very close to expectations
As the new cars will compete with the old cars in the upcoming season, much work went into balancing the aero package between the two
DPs using wide, front-mount water radiators positioned at shallow angles, the Corvette nose and inlet / outlet ducting was a simple task to fit, compared to the Dallara, which has used a tall and narrow, snout-like radiator since its introduction to the class. The Italian firm was therefore forced to move away from its unique layout in favour of a shared solution. Beyond tailoring the cooling and ducting across the three chassis to fit the needs of the Corvette
body and V8 engine, the other mechanical aspects of the cars went largely unchanged. Louth: ‘The development between the chassis manufacturers is really relegated to mechanical suspension, dampers, springs and other related systems, but the body is pretty much fixed.’ While Grand-Am did not
mandate specific aerodynamic targets for Pratt & Miller to hit with the Corvette DP, it did provide a close framework of what lift-to-drag (L/D) ratio
14
www.racecar-engineering.com • February 2012
Speedway in the lead up to the 50th running of the 24 Hours of Daytona in 2012, and Louth says he is confident a competitive balance can be achieved before the landmark event. ‘We’re working with Grand-Am on various rules and aerodynamic elements to achieve aero performance targets that are as good or better than the current cars, with the understanding that in the first year there would be both new and old cars, and there would be a balancing process to make sure all cars can compete on a level playing field. ‘We were in the wind tunnel
with Grand-Am looking at aero balance mechanisms between the new and old cars. Our design engineers had a full kit of spoilers, front under wing insets, wickers, blockers, tunnel fillers and things like that, which we could apply to the car depending on what we found. When we finally got to the track, we saw the cars aren’t that far apart, just a few miles an hour here and there. ‘After the two days on track
at Daytona we had a more complete understanding of the car that was at the tunnel test. And everybody kind of
TECH SPEC Daytona Prototype Generation 3
Chassis: tubular frame by Dallara, Coyote or Riley Technologies Wheelbase: 108-110in
Suspension: double wishbone with pushrod-actuated dampers
Steering: power-assisted rack and pinion
Transmission: Xtrac 386 or EMCO six-speed sequential (five-speed if using a 5.0-litre V8)
Brakes: maximum of six-piston calipers, multiple manufacturers
Engines: six or eight cylinders, fuel-injected engines from GM, Lexus, BMW, Porsche (two options), Ford, Infiniti and Honda. All approx 500bhp, maximum 5.0-litres
Fuel capacity: 24 US gallons
Weight: 4.0-litre and above: 1032kg Up to 4.0-litres: 1010kg
Cost: $400,000-$500,000
breathed a sigh of relief that the differences were in no way insurmountable, using relatively simple tuning devices or balance adjustment mechanisms. Whether it’s mandatory wickers, wicker heights, maximum wing angle of attack or so on. It was a lot closer than I thought it might’ve been.’ Whether the arduous task of outfitting three different chassis with the Corvette DP body will pay off with a championship win in 2012 is unknown but, from a marketing standpoint, the relatively limited costs involved to generate a custom DP body – said to be between $750,000 (£481,000) to $2.5 million (£1,603,415) – makes GM’s choice to green light the Corvette DP a winner as, with Ford and BMW sticking with its pre- existing plans to supply engines, it looks likely to have the next generation body market to itself for the coming year. For all of the engineering resources it required and races it might win, it’s hard to deny that in the performance category that matters most to US car manufacturers, the Corvette DP has a firm lead over its rivals in the race to the showroom floor.
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100