IMSA has unveiled a comprehensive set of revised Balance of Performance (BoP) figures for both the GTP and GTD classes, setting the stage for an intensely competitive Monterey SportsCar Championship at WeatherTech Raceway Laguna Seca.
These adjustments, released just days before the event, reflect IMSA’s ongoing commitment to parity among diverse manufacturer entries, addressing performance disparities observed in earlier rounds like the Rolex 24 at Daytona, the 12 Hours of Sebring, and the streets of Long Beach.
The GTP category, featuring the pinnacle of hybrid-powered prototypes from Acura, Aston Martin, BMW, Cadillac and Porsche sees nuanced tweaks that reflect data gathered from previous rounds.
The Acura ARX-06 receives a modest minimum weight reduction to 1,056 kg, a -3 kg shift following its recent Long Beach victory in the hands of Renger van der Zande and Nick Yelloly.
Meanwhile, the Aston Martin Valkyrie maintains its minimum weight at 1,030 kg with no alterations, preserving the advantage it has held since Sebring and positioning it as the benchmark for power-to-weight efficiency at 2.259 seconds in low-speed sectors.
The Cadillac V-Series.R receives a 15 kg weight reduction, while the 2026 and 2025-spec Porsche 963s drop 16 kg and 8 kg, respectively. The Porsche Penske Motorsport entries remain to be the heaviest in GTP at 1084 kg.
In terms of power output, the Valkyrie still holds the maximum power at 520 kW, while Acura has received the biggest adjustment, a 1.5 percent increase in Stage 1 but a much less 0.3 percent boost at Stage 2 for speeds over 200 km/h.
BMW holds a 0.5 percent increase in Stage 1 and 1.5 percent reduction in Stage 2, with the Cadillac also gaining 0.2 percent in the first stage and 1.1 percent reduction in the second stage.
The 2026-spec Porsche maintains same power levels it ran at Long Beach, albeit the JDC-Miller Motorsports Porsche gets a 1.3 percent increase in Stage 2 levels.
In a notable shift for the GTD ranks, the Aston Martin Vantage GT3 Evo, which currently leads the GTD class standings, has been granted a substantial 41 kg minimum weight reduction.
The Ford Mustang GT3 EVO follows at -15 kgs, the BMW M4 GT3 EVO at -12 kg and Porsche 911 GT3 R Evo at -11 kg. Meanwhile, the Ferrari 296 GT3 Evo has received a 10 kg weight increase, with the Corvette also gaining 4 kg.
In terms of power changes, the biggest movers are the Porsche has received the biggest power adjustment at 7.6 percent increase in Stage 1 and 4.3 percent decrease in Stage 2.
IMSA Laguna Seca BoP 2026
GTP Class (vs. Long Beach)
| Car Model | Min Weight (kg) | PWR (kg/kW) – S1 | PWR (kg/kW) – S2 | Max Power (kW) – S1 | Max Power (kW) – S2 | Max RPM | Max Stint Energy (MJ) | Energy Replenishment Rate (MJ/sec) |
|---|---|---|---|---|---|---|---|---|
| Acura ARX-06 | 1,056 (-3) | 2.079 (-0.038) | 2.087 (-0.010) | 508.04 (+7.80) | 505.96 (+1.04) | 9512 | 904 (+3) | 22.600 (+0.075) |
| Porsche 963 (2025) | 1,052 (-8) | 2.107 (-0.033) | 2.079 (-0.044) | 499.20 | 505.96 (+6.76) | 8158 | 895 (-11) | 22.375 (-0.275) |
| Porsche 963 (2026) | 1,084 (-16) | 2.259 (-0.016) | 2.085 (-0.031) | 479.96 | 520.00 | 8158 | 891 (-22) | 22.275 (-0.550) |
| Cadillac V-Series.R | 1,043 (-15) | 2.045 (-0.025) | 2.089 (-0.006) | 510.12 (-1.04) | 499.20 (-5.72) | 8800 | 901 (-5) | 22.525 (-0.125) |
| BMW M Hybrid V8 | 1,042 (-17) | 2.034 (-0.023) | 2.100 (-0.001) | 512.20 (-2.60) | 496.08 (-7.80) | 8000 | 902 (-6) | 22.550 (-0.150) |
| Aston Martin Valkyrie | 1,030 | 1.981 | 1.981 | 520.00 | 520.00 | 8400 | 913 | 22.825 |
PWR – Power-to-Weight Ratio, S1 – Stage 1 <190 kph, S2 – Stage 2 >200 kph
GTD Class
| Car Model | Min Weight (kg) | Max RPM | Max Power (%) – S1 | Max Power (%) – S2 | Max Stint Energy (MJ) | Energy Replenishment Rate (MJ/sec) |
|---|---|---|---|---|---|---|
| Lamborghini Huracán GT3 EVO2 | 1342 | 8300 | 89 | 89.2 | 889 | 22.225 |
| Lamborghini Temerario GT3 | 1337 | 8000 | 90.4 | 89.7 | 893 | 22.325 |
| Ferrari 296 GT3 EVO | 1350 | 7750 | 85.1 | 90.7 | 862 | 21.550 |
| Mercedes-AMG GT3 | 1356 | 7900 | 91.6 | 87.5 | 898 | 22.450 |
| Porsche 911 GT3 R (992) | 1373 | 8950 | 97.2 | 95.7 | 867 | 21.675 |
| Corvette Z06 GT3.R | 1360 | 8000 | 97.5 | 98.7 | 885 | 22.125 |
| Lexus RC F GT3 | 1356 | 7200 | 96.1 | 100.0 | 920 | 23.000 |
| McLaren 720S GT3 EVO | 1327 | 8100 | 94.5 | 90.7 | 880 | 22.000 |
| Aston Martin Vantage GT3 EVO | 1287 | 7000 | 85.9 | 83.4 | 833 | 20.825 |
PWR – Power-to-Weight Ratio, S1 – Stage 1 <170 kph, S2 – Stage 2 >180 kph
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