12 Hours of Sebring new BoP

December 7-8, 2023 we relayed the IMSA-sanctioned test at Daytona which aim was to establish Balance of Performance (BoP) tables for the 2024 season. Different tests were asked to the teams during those two days: short and long stints, little petrol, new tires, PRO drivers while driving , etc… in order to recover as much data as possible to establish the most equitable BoP possible.

Since the 24 hours of Daytona, a working group, with all relevant parties, worked on a new version to give the most perfect copy as possible to the 72nd running of the Mobil 1 Twelve Hours of Sebring, the second round of the IMSA championship.

📷 © Luc Warnotte at Sebring. Pipo Derani and Cadillac count 4 victories at the 12 Hours of Daytona since 2016. A Cadillac won the two last edition of the second race of the IMSA Championship: Cadillac Racing #01 in 2022 (bottom) and Whelen Cadillac Racing #31 (above) in 2023.

The IMSA Balance of Performance (BoP) for the 12 Hours of Sebring event was released through IMSA TECHNICAL BULLETIN IWSC #24-34.

Those figures are set through a highly sophisticated program, linked to the configuration of the track, the simulations carried out in wind tunnel, the engines on the test benches, tests at Daytona, data from previous races and number of meetings/adjustments made in collaboration between IMSA and manufacturers engineers. We make some factual comparisons between type of cars in GTP and GTD (PRO) classes.

Grand Touring Prototype (GTP) entries

We copy the original BoP table for GTP entries in table 4 at bottom of this news.

In table 1, we compare the numbers versus a base line: the BMW M Hybrid V8 which happens to be the lowest for each metric. Table 2 gives you a comparison between last year numbers and the actual ones.

Table 1: GTP BoP differences with BMW M Hybrid V8 as base line

Comparing to the BMW M Hybrid V8 as base line, the Cadillac V-Series.R will be 30 kg heavier, when the Acura ARX-06, Lamborghini SC63 or the Porsche 963 will be respectively 25, 14 and 19 kg heavier.

As a compensation, the V-Series.R wins 14 kW, when the ARX-06, the SC63 and the 963 win 6, 7 and 2 kW respectively.

Also of importance, the maximum energy consumption per stint: obviously this metric is correlated to the maximum power as the V-Series.R wins 20 MJ, when the ARX-06, the SC63 and the 963 have 12, 10 and 6 MJ respectively more than the BMW M Hybrid V8.

Table 2: GTP BoP differences between 2023 and 2024.

Last year champion Cadillac V-Series.R will be 22 kg heavier and gain 7kW in maximum power as well as 13 MJ as maximum stint energy.

Both Acura ARX-06 and Porsche 963 gain a little kg in weight but see their maximum power reduce by 8 and 9 kW respectively as well as their maximum sting energy is reduced respectively by 7 and 8 MJ respectively.

The BMW M Hybrid V8 will be 10kg lighter but get a maximum power and maximum stint energy reduced by 7 (kW and MJ).

The premier GTP category sees the debut of the #63 Lamborghini SC63, hence no comparison is possible for that car.

Grand Touring Daytona (GTD PRO and GTD)

As one might expect since BMW M GT3 and Ferrari 296 GT3 lost their championships points at Daytona (and a 25.000 $ penalty) after using a performance level beyond the data provided before the 24 Hours of Daytona, both are penalised in terms of average power (respectively -9,1 and -9,0 kW).

The Ford Mustang GT3 was already the lightest car (1.315 kg) and will get its weight reduced by 15 kg which is 105 kg lighter the the heavier car in class: the Mercedes AMG GT3.

The ROLEX 24 at Daytona winner is penalised with a 35 kg ballast still receiving the highest average power delta… which, on its own, is not relevant as we don’t know what the base line is comparing to the other cars.

Any conclusion based on those numbers would be hazardous! The least one could say is that the BoP evolves, produces the fairest possible races, enables to point the “cheaters” and will get better with time.

Table 3: BoP Grand Touring Daytona (GTD PRO and GTD) published

Source: IMSA

IMSA TECHNICAL BULLETIN IWSC #24-34 BoP GTP table

Table 4: BoP Grand Touring Prototype (GTP) published

Source: IMSA

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📷 © Luc Warnotte at Lusail (Qatar). 2024 Twelve Hours of Sebring entry list analysis

📷 © Luc Warnotte at Daytona 2024. Reigning GTP champion Derani previews Sebring.

📷 © Luc Warnotte at Daytona 2024. Porsche wins Rolex 24

📷 © Luc Warnotte at Daytona 2024. Cadillac on top of ROLEX Thursday practices.