IMSA tweaks DPi BoP ahead of Road America

IMSA has returned some of the performance taken from its Daytona Prototype internationals for this weekend’s visit to Road America.

Consecutive wins by spec P2 teams in the WeatherTech SportsCar Championship’s Prototype class has led to new Balance of Performance freedoms for all four DPi manufacturers. Some, starting with Acura’s ARX-05 run by Team Penske, received less of a break than other models.

Power, weight, and turbocharger boost concessions were not made for the Acura, but IMSA has granted the ORECA-based DPis an extra two liters of fuel (now 71L total).

Cadillac’s DPi-V.R, run by the Action Express Racing and Wayne Taylor Racing teams, will have more power, thanks to a combined 0.9mm increase in airflow to its 5.5-liter V8 engines (now 31.6mm total opening size). To compensate for the extra power, the Dallara-based Cadillacs will have an additional four liters of fuel to burn during each stint (now 68L total).

Mazda’s RT24-P, the only DPi model without a win in 2018, has been given the greatest round of adjustments. The Riley/Multimatic-based Mazdas have been granted a 10 kilo weight reduction (now 915kgs), an increase in boost pressure throughout its 9200rpm rev range (with an emphasis on low-end and top-end power), and will have four more liter of fuel capacity to feed the 2.0-liter four-cylinder engines (now 78L total).

Tequila Patron ESM’s Nissan Onroak DPis also received four more liters of fuel (now 80L total) which will be needed, thanks to boost increases across the 7700rpm rev range with the 3.8-liter twin-turbo V6 motor installed in the back of its Ligier-based prototypes.