Following two wins in a row and a season-long podium streak by the #31 Action Express Cadillac, the V-Series.R received a 21-kilogram weight penalty that dominated the headlines when released last week.
However, as usual, we need to take a closer look at the BoP sheets to see how much of a disadvantage the naturally aspirated V8-powered LMDh is carrying into the inaugural 6-hour race at Road America.
The legendary circuit near Elkhart Lake is a very different playground when compared to The Glen, where the GTP class held its last race. Road America features three long flat-out sections mixed with a large number of 2nd to 3rd gear corners – unlike Watkins Glen International with its faster, sweeping turns.
A weight penalty always hits hard, but nowhere harder than in fast corners. That’s why the Porsche 963 received a weight break for Watkins Glen after its 1,100-kilogram outings on the street circuits of Long Beach and Detroit, though it wasn’t any more competitive still being the heaviest GTP car.
Still, Road America features the long Carousel and the ultra-fast Turn 1 where additional weight hurts. Yet, there are many sections where lateral grip counts, making Road America such an iconic circuit with a variety of corners.
Below 230 kph (143 mph)
As usual, we’ll take a look at the power-to-weight ratios first:
- Aston Martin Valkyrie — 1.962 kg/kW
- BMW M Hybrid V8 — 1.981
- Acura ARX-06 — 2.030
- Cadillac V-Series.R — 2.068
- Porsche 963 old — 2.099
- Porsche 963 — 2.124
The hybrid-less Aston Martin Valkyrie still boasts the best power-to-weight ratio, but it is expected to suffer from its top speed deficit on the long straights. For the first time in 2026, Cadillac’s power-to-weight ratio is significantly worse than Acura’s, after being rated more favorably at the beginning of the year and sitting on roughly the same level since Detroit.
Notably, the gap between the BMW M Hybrid V8—which scored the final RLL-run victory at Elkhart Lake last year thanks to a clever strategy—and Acura/Cadillac has also increased significantly.
This becomes especially evident when comparing the power-to-weight ratios to Watkins Glen:
- BMW M Hybrid V8 -0.024 kg/kW
- Porsche 963 -0.018
- Acura ARX-06 -0.014
- Aston Martin Valkyrie +-0.000
- Cadillac V-Series.R +0.025
- Porsche 963 old +0.064
BMW, having already enjoyed a relatively favorable power-to-weight ratio since Detroit, received the biggest break. On the other hand, the Cadillac V-Series.R, after starting the season with the most favorable power-to-weight ratio of all cars, is now only surpassed by the two Porsche models.
Ever since Long Beach, the factory Porsches have been paying a high price for their major successes at the start of the year, but they are slowly gliding back into the pack BoP-wise. Meanwhile, the private JDC-Miller Porsche received the biggest hit in terms of BoP compared to Watkins Glen.
However, when comparing the values to Road America 2025, the picture changes completely:
- Porsche 963 old -0.081 kg/kW
- BMW M Hybrid V8 -0.067
- Porsche 963 -0.056
- Acura ARX-06 -0.030
- Aston Martin Valkyrie -0.019
- Cadillac V-Series.R -0.012
First of all, every car receives a break in terms of BoP. However, keep in mind that all four LMDh models received technical updates over the winter, whereas only the 2025-spec Porsche of JDC-Miller and the Aston Martin Valkyrie (built under LMH regulations) are running in last year’s specification.
Here, it is the 2025-spec Porsche that receives the biggest break. This is largely down to Porsche having to run the 2025 season with very low power below 230 kph. The 963 is still heavier than in 2025, but both models have received a massive power boost.
Again, the BMW M Hybrid V8 gets a massive BoP break. Acura, despite setting the two fastest laps in the 2025 race, also received a medium boost. Aston Martin, having run at 1,030 kg and 520 kW back in 2025, didn’t have much room for improvement as the Cadillac gets a slight break because it runs only 3 kilograms heavier than in 2025. Nevertheless, it is the smallest gain of all cars.
Above 240 kph/149 mph
Road America is one of the few tracks on the calendar where the high-speed range really matters. With three extensive flat-out sections, cars spend a significant percentage of a lap above 240 kph in a (more or less) straight line.
The power-to-weight ratio standings look as follows:
- Aston Martin Valkyrie — 1.962 kg/kW
- Acura ARX-06 — 2.010
- BMW M Hybrid V8 — 2.011
- Cadillac V-Series.R — 2.033
- Porsche 963 old — 2.063
- Porsche 963 — 2.067
The rather draggy Aston Martin still leads the chart, but the other cars have closed the gap a bit since Watkins Glen. This is expected to show much more at Road America thanks to the aforementioned circuit characteristics.
Compared to Watkins Glen, the changes are relatively minor:
- BMW M Hybrid V8 -0.033 kg/kW
- Porsche 963 old -0.028
- Acura ARX-06 -0.008
- Aston Martin Valkyrie +-0.000
- Porsche 963 +0.003
- Cadillac V-Series.R +0.028
Here, Cadillac receives the biggest hit by a considerable margin because, unlike in the lower-speed range, the higher weight isn’t compensated for by a higher power output. The only other car to receive a worse power-to-weight ratio is the 2026-spec Porsche, though its BoP remains far better than it was at Long Beach, Laguna Seca, and Detroit.
Again, the BMW M Hybrid V8 emerges as the big winner, while the 2025-spec Porsche receives a more favorable high-speed power-to-weight ratio than its 2026-spec sister car for the first time since Laguna Seca.
Compared to Elkhart Lake 2025, the adjustments are mostly minor again:
- BMW M Hybrid V8 -0.048 kg/kW
- Aston Martin Valkyrie -0.019
- Porsche 963 old -0.010
- Porsche 963 -0.006
- Acura ARX-06 -0.006
- Cadillac V-Series.R +0.006
The only exception is BMW, which receives a massive break compared to last year, leaving Cadillac once again at the bottom of the table. Unlike in the sub-230 kph range, Porsche doesn’t get a major break compared to the previous year and stays at its relatively unfavorable rating—albeit with more power and more weight compared to 2025.
Conclusion
Given the numbers, it should be BMW’s race to lose. But we said that back at Detroit and Watkins Glen as well. Nevertheless, BMW could have won on both occasions, just as it has done twice in the FIA WEC now.
Looking strictly at the data, BMW must be considered the favorite, but keep an eye on Acura. Meyer Shank Racing was in a prime position to win the race in 2025 before BMW pipped everyone with a clever strategy, anticipating the final caution.
It will be tough for Action Express to keep their podium streak going based purely on the numbers. Additionally, the #31 had a rare uncompetitive outing at Road America in 2025. On the other side, Wayne Taylor Racing looked very competitive until an incident with one of the factory Porsches put it out of contention.
It will still be fascinating to watch the evolving characteristics of the Porsche 963, which is undergoing a transformation similar to Watkins Glen with far more power and weight compared to 2025. And Aston Martin? The Valkyrie is still awaiting its upgrades over the upcoming winter. We don’t expect it to be any stronger than at The Glen prior to its unfortunate accident under Full Course Yellow.
Of course, you need the speed, but as 2025 showed, a clever strategy in IMSA GTP racing can more than make up for the last tenth of a second on the road.
BoP 2026 Motul SportsCar Endurance Grand Prix
(Differences to Watkins Glen 2026 / Road America 2025 in parentheses)
Acura ARX-06
Min. Weight: 1,045 kg (+0 kg / +7 kg)
Max. Power <230 kph: 514.80 kW (+3.64 kW / +10.92 kW); 690 hp
Max. Power >240 kph: 520.00 kW (+2.08 kW / +5.20 kW); 697 hp
Max. Engine Speed: 9,512 rpm
Max. Energy per Stint: 912 MJ (+1 MJ / +5 MJ)
Fuel Replenishment: 22.800 MJ/sec (+0.025 MJ/sec / +0.125 MJ/sec)
Aston Martin Valkyrie
Min. Weight: 1,020 kg (+0 kg / -10 kg)
Max. Power <230 kph: 520.00 kW (+0.00 kW / +0.00 kW); 697 hp
Max. Power >240 kph: 520.00 kW (+0.00 kW / +0.00 kW); 697 hp
Max. Engine Speed: 8,400 rpm
Max. Energy per Stint: 912 MJ (-2 MJ / +2 MJ)
Fuel Replenishment: 22.800 MJ/sec (-0.050 MJ/sec / +0.050 MJ/sec)
BMW M Hybrid V8
Min. Weight: 1,030 kg (+0 kg / -3 kg)
Max. Power <230 kph: 512.20 kW (-1.56 kW / +9.36 kW); 687 hp
Max. Power >240 kph: 520.00 kW (+16.12 kW / +19.76 kW); 697 hp
Max. Engine Speed: 8,000 rpm
Max. Energy per Stint: 906 MJ (+5 MJ / +16 MJ)
Fuel Replenishment: 22.650 MJ/sec (+0.125 MJ/sec / +0.400 MJ/sec)
Cadillac V-Series.R
Min. Weight: 1,053 kg (+21 kg / +3 kg)
Max. Power <230 kph: 509.08 kW (+4.16 kW / +4.16 kW); 683 hp
Max. Power >240 kph: 517.92 kW (+3.12 kW / +0.00 kW); 695 hp
Max. Engine Speed: 8,800 rpm
Max. Energy per Stint: 908 MJ (+5 MJ / +1 MJ)
Fuel Replenishment: 22.700 MJ/sec (+0.125 MJ/sec / +0.025 MJ/sec)
Porsche 963 (2025 Homologation)
Min. Weight: 1,062 kg (+4 kg / +11 kg)
Max. Power <230 kph: 505.96 kW (-14.04 kW / +23.92 kW); 679 hp
Max. Power >240 kph: 514.80 kW (+8.84 kW / +7.80 kW); 690 hp
Max. Engine Speed: 8,158 rpm
Max. Energy per Stint: 906 MJ (-3 MJ / +10 MJ)
Fuel Replenishment: 22.650 MJ/sec (-0.075 MJ/sec / +0.250 MJ/sec)
Porsche 963 (2026 Homologation)
Min. Weight: 1,066 kg (-7 kg / +15 kg)
Max. Power <230 kph: 501.80 kW (+1.04 kW / +19.76 kW); 673 hp
Max. Power >240 kph: 515.84 kW (-4.16 kW / +8.84 kW); 692 hp
Max. Engine Speed: 8,158 rpm
Max. Energy per Stint: 907 MJ (-6 MJ / +11 MJ)
Fuel Replenishment: 22.675 MJ/sec (-0.150 MJ/sec / +0.275 MJ/sec)
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