Acura and Cadillac shine, BMW and Porsche falter at the Rolex 24

Acura and Cadillac shine, BMW and Porsche falter at the Rolex 24
Feb 2023

DAYTONA BEACH, FLA.--With just one race on the books, it's probably too soon to declare this the dawn of a new golden era in racing, but that thought was on many minds at last weekend's spectator-packed Rolex 24 at Daytona. The grueling 24-hour race is the season-opening event for the WeatherTech Sportscar Championship, and 2023 saw the introduction of a new class of hybrid prototype race cars called GTP (for Grand Touring Prototype).
The crowds were heavier than ever, buoyed by the debut of the new machines, which put on a good show. And the complicated new energy-based pit stop formula didn't appear to present anyone any trouble.
The same can't be said for the race itself. Twenty-four-hour racing is hard--I speak from some experience--and making it to the end should be, and is, a challenge. A 24-hour race as the first race of the year for all-new cars is even more difficult, despite the thousands of miles each car covered in testing over the past few months. As such, some feared we might be in for a repeat of 2003; that year saw a new prototype class introduced, the best of which finished 24 laps behind the winning car, a racing version of a Porsche 911.

But GTP proved more reliable than expected--six of the nine GTP cars finished the race without significant problems, with four still on the lead lap. It was a better weekend for some than others, though, with at least two cars requiring a change of their lithium-ion traction battery--no quick job.
It was LMDh--now it's GTP
The new class of cars allows for much more road car-like styling, which, combined with a mandatory hybrid system, has resulted in strong interest from automakers. This year, we saw cars from Acura, BMW, Cadillac, and Porsche, with Lamborghini and maybe Alpine joining the fun next year. IMSA, the sport's organizer, has even found a convergence formula with the organizers of the 24 Hours of Le Mans, opening up the prospect of even more new prototypes joining in next year from Ferrari, Peugeot, Toyota, and others.
But the development of these new GTP cars--also known as LMDh, or Le Mans Daytona hybrids--was not entirely smooth. The past two years have seen many supply chain disruptions and shortages, a fact that has delayed Porsche from building additional GTP cars for customers in addition to the cars it's running with the Penske team.

A GTP car starts with a carbon fiber chassis (sometimes called a spine) from one of four approved manufacturers (Dallara, Oreca, Multimatic, and Ligier), and each car uses a standard transmission from Xtrac, a standard electric motor-generator unit from Bosch, and a standard 1.35 kWh lithium-ion traction battery made by WAE. To this, a car manufacturer adds its own bodywork and styling--and, of course, a gasoline engine.
That's where we see the most diversity between the four different makes. All the cars look suitably different, with recognizable cues to each brand's road cars, and they all sound distinct thanks to different engine choices--Acura uses a twin-turbo V6, Porsche and BMW both went for twin-turbo V8s, and Cadillac opted for a naturally aspirated V8.

Acura and Cadillac shine, BMW and Porsche falter at the Rolex 24

Porsche was the first to begin testing in early 2022, and as such, the German OEM did a lot of the lead work integrating the different hybrid components and sharing notes with the other three manufacturers despite being ostensible rivals. By late summer, Acura, Cadillac, and BMW were also racking up hours of testing, but with tens of thousands more miles on the cars than the others, Porsche had to be considered the favorite going into the race.
Talk of spare parts shortages added an extra frisson of excitement. A wreck in one of the practice sessions could have spelled disaster but thankfully did not--some held their breath when Nick Tandy got caught by a gust of wind during qualifying and went into a tire barrier, but the damage was only cosmetic.