With the Roar Before the 24 only three weeks away, IMSA is in the process of finalizing the Balance of Performance for cars competing in next month’s TUDOR United SportsCar Championship season-opening Rolex 24 at Daytona.
As Scot Elkins, IMSA’s Managing Director of Technical Regulations, explains to Sportscar365, the sanctioning body has implemented a more thorough BoP process for 2015 that takes into account new data points collected through off-season wind tunnel and dyno testing.
“It mainly gives us information so we can address what we call sensitivities,” Elkins told Sportscar365. “If we know what the downforce is, it helps us on restrictor and weight adjustments and helps us make those changes that we have at our disposal a little bit more intelligently.”
The Rolex 24 will feature unique technical configurations for three of the four categories, including the Prototype class, which sees new P2 machinery with the Ligier JS P2 and HPD ARX-04b making their respective Daytona debuts.
Elkins said both of the new closed-top prototypes will be put through the wind tunnel next month to gain further data for the BoP process.
The P2 cars will run at the Roar in a provisional configuration based off the adjusted air restrictor and weight numbers used in the final two races of 2014, which showed improved pace for the Le Mans style prototypes.
“We started working at the end of [this year] increasing the restrictor and added weight to the P2 to try and get the tires up to temperature a little bit faster,” Elkins said. “We’ll just keep looking at that.”
Both the P2 and DP cars will continue to share the same Continental tire, with IMSA not in a position to have a P2-specific tire at this point, according to Elkins.
No significant changes are expected for either prototype platform, with P2 cars again required to use the Le Mans low-drag aero kit at Daytona and DPs to run without its diffuser for the opening round as well.
Elkins said there may be minor tweaks in the BoP between the Corvette DP and Riley-Ford, depending on the wind tunnel results of the new C7-inspired bodywork that will debut next month.
On the GT Le Mans front, cars will not run in the Le Mans-specific low downforce kits as originally proposed, with tweaks to instead be made to individual current aero packages.
“The manufacturers were kind of split 50/50 on whether they wanted to use the Le Mans kit or not,” Elkins said. “So we’re going to use the basic kit but making a few tweaks like removing some wickers and things like that to help specific manufacturers to run at Daytona a little better than they did last year.
“We’re working with the BMW and we’re working with the Aston and the Corvette guys and looking at a few things to try and help better the situation from last year, without going to the full Le Mans kit. The specifications of our cars are actually quite different than the WEC when it comes to aero.”
One of the biggest off-season overhauls has come in GT Daytona, with IMSA having dynoed engines and wind tunnel tested cars from each manufacturer in order to gather detailed data on how each car reacts to specific BoP adjustments.
“We were trying to do a little bit of a matrix to give ourselves an idea of how effective the changes are that we make,” Elkins explained. “We also got a baseline number on downforce and drag for every car.
“We looked at them exactly how they came off the track at Petit Le Mans and then we looked at them as they’d be configured for Daytona to give ourselves a better idea of those two configurations.”
While Elkins said the initial BoP tables for GTLM and GTD will be released prior to the Roar, he doesn’t necessarily expect the Prototypes to be in their final configuration during the three-day official test.
“I think we need to see how some of the prototypes behave at Daytona,” he said. “We haven’t run there yet with the new restrictor and the weight and all of that. Ideally, we don’t want to make too many adjustments between the Roar and the race.
“In terms of GT, we want to have that fixed going into there. And we want to be clear that the performance level that we see at the Roar is going to be the performance level we expect at the race, especially in regards to sandbagging.
“We want to keep an eye on that and have that locked down and not make changes between the test and the race.”
As was the case in 2014, IMSA will limit the number of BoP adjustments to a total of four over the course of the season, including one between Daytona and the Twelve Hours of Sebring.
With a full year under their belts, Elkins and the IMSA technical staff feel confident of delivering a competitive platform to teams, manufacturers and fans in 2015.
“The thing we want people talking about is the great racing and we had that [in 2014],” Elkins said. “I think that’s what we want everyone to talk about, not the AoP changes, but that it’s been great racing on the track.”