Both Specs of Porsche 963s Get Weight Increases for Detroit

Photo: Jurgen Tap/Porsche

Both versions of the Porsche 963 will contest next weekend’s Chevrolet Detroit Sports Car Classic with additional weight, with the 2026-spec Porsche Penske Motorsport entries returning to its 1,100 kg weight from Long Beach.

Released Thursday by IMSA, the Balance of Performance for the 100-minute street race sees all but the Aston Martin Valkyrie adjusted, which remains at the baseline 1030 kg minimum weight and maximum 520 kW of power at both stages.

However, the BMW M Hybrid V8 has been adjusted down to the minimum weight as well, shedding 12 kg since the most recent round at WeatherTech Raceway Laguna Seca.

Both the Acura ARX-06 and Cadillac V-Series.Rs have both lost 5 kgs.

However, the factory Porsches will run with 16 kg of additional weight, with the Laguna Seca-winning JDC-Miller Motorsports 963, which runs in 2025-specification, getting a significant 30 kg weight increase.

It is slightly offset with a 2.7 percent increase in power at speeds less than 190 km/h, and a 1 percent increase in Stage 2 power.

By comparison, the 2026-spec Porsches get a 1.5 percent increase in Stage 1 and remain unchanged, at the 520 kW maximum, in Stage 2.

The BMW has the biggest power swing, losing 1.5 percent and 3.1 percent, respectively, of power, likely to counter the  notable weight break.

The Acura, meanwhile, gets 2.1 percent of additional power at the low-end, but will face a 1.1 percent reduction in the second stage, while the Cadillac is relatively unchanged, with no adjustment at Stage 1 and just a 0.2 percent decrease in Stage 2.

Weight Additions for Majority of GTD Pro Entries

All but two GT3 models competing in GTD Pro next weekend have received weight increases, while second stage power levels have mostly been reduced across the board.

The Chevrolet Corvette Z06 GT3.R (+10 kg) as well as the Ford Mustang GT3 EVO and Porsche 911 GT3 R Evo (both +11 kg) are the heaviest hit in the weight department, while the BMW M4 GT3 EVO (+4 kg) and McLaren 720S GT3 Evo (+3 kg) being less affected.

Both the Lamborghini Temerario GT3 and Lexus RC F GT3, however, will remain at the same weights it ran at Laguna Seca.

The new-for-2026 Temerario GT3, however, will face its first power reduction, in the form of a 2.5 percent decrease in the first stage and 1.7 percent at Stage 2.

Both the BMW (-4.6 percent) and Lexus (-4.2 percent) have the largest power reductions at the second stage, while the Porsche gets a 4.5 percent decrease in Stage 1 but 1.6 percent increase in Stage 2.

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