Pirelli World Challenge and SRO Motorsports Group have rolled out with a high altitude-specific Balance of Performance for this weekend’s round at Utah Motorsports Campus, in an effort to close the gap between normally aspirated and turbocharged cars.
A new “Category H” BoP has been established for Utah, which was previously grouped as a Category C track in SRO’s four-tier variable track-based BoP system that’s been used in PWC and other championships such as the Blancpain GT Series for the last two seasons.
According to PWC Director of Competition Marcus Haselgrove, data and analysis from last year’s race at Utah was used to formulate the new track-specific BoP.
“We did it [after] last year because all of the manufacturers said you need to do a special BoP and we agree,” Haselgrove told Sportscar365.
While a number of cars have received weight and RPM adjustments, Haselgrove said the biggest change has been with the adjusted atmospheric pressure, which has resulted in significantly reduced boost pressures for turbocharged cars.
Previously, there was no compensation made between the two different engine types, which gave an edge to the turbos, which do not lose as much power at higher altitudes as normally aspirated powerplants.
“The biggest difference you’ll see is that we’ve taken the ambient pressure as the pressure here,” Haselgrove explained.
“Instead of using everything corrected to 1010 [millibar], it’s corrected to 850 [mb]. That’s why we’ve done it, because the correction factor is huge. This is more accurate.”
Haselgrove said the Category H BoP would theoretically be used for any track 3,000 feet or above sea level, with Tooele, Utah standing at 4,500 feet.
At 7,400 feet, Autodromo Hermanos Rodriguez is the only other modern-day circuit in a higher altitude.
“Anywhere [an SRO-managed BoP series] go, where they have high altitude or extenuating circumstances, they’ll do a specific BoP,” Haselgrove said.
“There’s not many places in the world you have to do it. It’s just here for us.”
The adjustments have been made to only GT3 and GT4-spec cars competing this weekend, with GT Cup entries remaining unchanged from its base configuration.