IMSA released late Friday the expected final set of Balance of Performance adjustments, as well as Prototype class aerodynamic specifications for next weekend’s Mobil 1 Twelve Hours of Sebring.
Following weeks of wind tunnel testing, the sanctioning body has finalized the high downforce configurations for all of Prototype class cars, which will be run at the majority of events, including the upcoming 12-hour endurance classic.
Included in the most recent bulletin are specifications for the Corvette-bodied DPs, Ford-Riley, HPD/Dinan-Riley and P2-based prototypes.
The biggest change from Daytona comes with the addition of the IMSA-developed diffuser for DP cars, along with the allowance of additional dive planes to help offset the increase in rear downforce.
P2 cars, meanwhile, will run in full ACO specification with its high-downforce aero kits. The cars were in low-downforce, Le Mans-style trim at Daytona.
On the BoP front, Chevrolet-powered DPs will have a 0.7 mm reduction in air restrictor diameter, compared to what they ran at Daytona, along with the installation of a rev limiter set to a max of 7450 RPM.
The Ford-powered DPs, meanwhile, sees a 0.6 mm larger diameter, giving the EcoBoost engines an increase in power. It’s the same sized restrictor as the new HPD DP engine, which makes its debut next weekend with Starworks Motorsport.
Boost pressures have been adjusted for the Ford (1695 to 1765 mbar) with the HPD set to use 1844 mbar.
No changes have been made to any of the P2 powerplants, which remain in the same specification as Daytona. The same is the case for the DeltaWing.
Only minor BoP changes have been made in both production-based ranks, with the majority of GTLM cars seeing a slight reduction in fuel capacity compared to the last bulletin issued in mid February.
The Corvette C7.R sees a 7-liter reduction in fuel capacity, while both the SRT Viper GTS-R and Aston Martin Vantage V8 will be permitted two fewer liters. The Porsche 911 RSR, meanwhile, has faced a 1-liter decrease.
BMW’z Z4 GTE car, meanwhile, will be permitted to use a 10mm taller gurney, while the Aston Martin, which withdrew from Sebring, has been given a further 30kg weight break. Additionally, the Z4 will be permitted to use modified door sills
The GTD category sees a class-wide increase in fuel capacity and greater flexibility in rear wing placement.
Additionally, the Porsche 911 GT America will be permitted to use the DP specification Crawford rear wing instead of the category’s standard wing used on the majority of GTD cars at Daytona.