IMSA Takes Full Control of BoP

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IMSA has changed the Balance of Performance process for the GTD Pro & GTD classes beginning with next weekend’s Mobil 1 Twelve Hours of Sebring presented by Cadillac, largely reverting to a system based from last year but with increased manufacturer transparency.

Confirmed in a media roundtable on Friday morning, the sanctioning body, in support of the manufacturers, has re-taken control of the BoP process, following a system that was put into place ahead of the 2024 season that had manufacturers nominate its own performance expectations.

That system, which took into account data from December’s IMSA-sanctioned test at Daytona International Speedway, led to post-race penalties for both Ferrari and BMW for having “exceeded IMSA’s expectations as shared in the GT manufacturers technical working groups.”

Instead, IMSA’s technical committee will now declare BoP figures for the GT3 platform themselves, with full transparency between the manufacturers, as had previously been the case.
It was cited that the lack of a sanctioned BoP test at Sebring International Raceway prior to the event, along with manufacturer feedback, led to the reversal of its previous system.

IMSA’s senior technical director Matt Kurdock explained:
“We concluded a technical working group yesterday with the OEMs discussing the process, discussing the performance targets for Sebring and the OEMs felt that carrying on in a manner where working towards a common performance targets would prove to be difficult, particularly as there was opportunity to conduct a Sebring sanctioned test.

“IMSA has taken some of the 2023 data in combination with some of the Rolex 24 data and has since devised a BoP solution for Sebring that’s basically a combination of those sources of data available with trying to hit a common performance target for the GTD and GTD Pro classes for the Sebring event.”
Kurdock added:
“The manufacturers felt it was too difficult to work towards a common target. Having to perform the work in setting the parameters that hits a series of common targets.

“They’ve asked IMSA to retain the control going into Sebring, particularly as there’s no opportunity for a sanctioned test where we can go through in a sanctioned test and further collect imperial data whether the targets we’re devising are appropriate.
“In this case we’ve gone with a more traditional method of defining the BoP but continuing on with the increased transparency that IMSA has developed with the OEM group in providing a common forum for us to discuss it collectively.”

IMSA VP of competition Simon Hodgson indicated that the Daytona outcome led to the manufacturer’s decision to ask the sanctioning body to take the BoP back under IMSA’s own control.
“I think there’s been a realization, a recognition from the manufacturer group that the complexity in defining performance targets is difficult,” he said.
“So they’ve asked IMSA to revert to controlling the BoP process as we move forward for the rest of this year.”

IMSA released its Sebring BoP document on Thursday afternoon, featuring wholesale changes to weight, power and fuel capacity for nearly all the 11 GT3 models since January’s season-opener.
Kurdock said that the BoP parameters are independent of the penalties issued post-race at Daytona.

Adjustments have also been made to the GTP class, including the starting BoP for the new Lamborghini SC63, which will make its series debut next weekend.
Kurdock confirmed that the GTP class runs to a different BoP system from that in GTD Pro/GTD and the procedure remains unchanged amid the rollback for the production-based classes.
He added that there are no other planned sanctioned tests for the remainder of this season.

 

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From the beginning of the current-era GTP class, IMSA and FIA have used torque sensors collars on the LMDh cars’ halfshafts to measure power and energy output. For next season, in order to add to the data they already are using to set Balance of Performance, the series is considering implementing similar technology in the GT categories as well.

“In 2025, we’re looking at some significant technical regulation changes for the GTD and GTD PRO classes with the introduction of torque sensors, similar to what’s been done in LMGT3,” said Matt Kurdock, IMSA’s senior technical director, during a media roundtable discussion on the Balance of Performance process.

“I think the opportunity to not only make sure that the technology is integrated correctly with IMSA’s electronics in the car, but to also get some sample data on the cars in controlled conditions, is something that we would very much like to do. But we’re still checking on the feasibility of doing that.”

The FIA is using torque sensors on the LMGT3 cars that were introduced to the World Endurance Championship this season, and as the two series and ACO are working to implement convergence of the rules, it seemed likely that IMSA would follow.
The sensors would not only supply additional data to the series, but could also be used to implement things like virtual energy in a stint, as exists in GTP.

“That is something we’re working with the GTD manufacturer group right now, is pushing forward to work on updating the technical regulations with that equipment,” Kurdock explained. “I think we’ve had a very positive experience with it in GTP not only in the ability to control power, with a common methodology and a common measurement, but also to implement things like virtual energy, which allows for, we believe, better competitive equivalency between the different power train architectures and the ability to basically get more equivalency on giving up pace for gaining stint length.”