IMSA’s Kurdock Explains Evolution in GTP BoP Process

Photo: Jake Galstad/IMSA

“Demonstrative performance” has been incorporated into this year’s Balance of Performance process for the GTP class, which has added further data points according to IMSA senior technical director Matt Kurdock.

The sanctioning body clarified the evolutionary change to the BoP process during a media roundtable ahead of this weekend’s Mobil 1 Twelve Hours of Sebring presented by Cadillac.

The new-for-2023 GTP class, which featured all cars built to LMDh technical regulations, saw minor BoP tweaks throughout its first season, with IMSA utilizing simulation data for each track.

It has since expanded its data bank to include on-track performance, in a change for this year.

“Working collectively with the GTP manufacturers in a common forum, much like we’ve done with the GTD manufacturer group, we talked about an evolution of the GTP BoP process going into Daytona and Sebring,” Kurdock said.

“We felt like it was necessary to capture some of the demonstrative performance from last year, particularly towards the end of last season, as cars were more well developed, and incorporating that into the BoP process.

“The changes you see for Sebring are incorporating some of the end-of-season performance as well as adjusting for performance observed at Daytona.

“We certainly learned a lot from Daytona, particularly in the ability for cars to compete over the course of a stint and some of the adjustments you see in Sebring are reflective of us considering that Daytona performance as well.”

The BoP for Sebring sees several weight swings compared to the cars’ configurations run at January’s season-opening Rolex 24 at Daytona, with the Cadillac V-Series.R the heaviest hit with a 30 kg increase since Daytona and 22 kgs heavier than last year’s configuration at Sebring.

The Acura ARX-06, meanwhile, has been given a a 17 kg weight break since Daytona, while the BMW M Hybrid V8 and Rolex 24-winning Porsche 963 have shedded 1 kg and 2 kgs, respectively.

In terms of power, Porsche has a 11 kW (14 hp) reduction compared to Daytona, which is 9 kW less than its configuration at last year’s race on the Florida airfield circuit.

The Cadillac’s weight increase has been offset with a 10 kW (13 hp) increase in power from Daytona, while the Acura and BMW have both lost 8 kW (11 hp).

Figures for maximum stint energy and stint energy replenishment rate have also been adjusted, in an effort to equalize stint lengths.

Lamborghini’s SC63, which will make its WeatherTech SportsCar Championship debut this weekend, will weigh in at 1044 kg, as the second-lightest GTP class car, along with 513 kW of maximum power and with 908 MJ of maximum stint energy.

IMSA’s senior performance and simulation engineer Bill Pearson explained that they were unable to use the SC63’s data from its run in December’s sanctioned test at Daytona for BoP purposes.

“When we saw the data that we got at the test in December, if we’re going to look at that car’s data, we have to look at all the other cars’ data at that test as well,” he explained.

“And obviously, when people are testing, they’re doing different things.

“The sanctioned test that we put in place for the GTD process was very, very rigorous in terms of what we controlled. We controlled so many parameters and put so many people and so much investment in that that we felt we could trust that data.

“The same can’t be said of the data that we see when we were testing and we’re not controlling in the same way.

“Whilst of course we’ve got one eye on what’s happening, we are very much, the process that we’re putting in place for GTP this year does not include that test data.

“So for the Lamborghini, we’re not able to use their use that data because we’re not using it for anybody else.”

John Dagys

John Dagys is the founder and Editor-in-Chief of Sportscar365. Dagys spent eight years as a motorsports correspondent for FOXSports.com and SPEED Channel and has contributed to numerous other motorsports publications worldwide. Contact John