IMSA is the American sister of the WEC — and in many ways its rougher, older brother. Sebring since 1952, Daytona since 1962, Watkins Glen since the 1960s. IMSA holds the longer unbroken history in sports car racing.
What it is
- Around 11 races per season on American and Canadian circuits
- Four classes: GTP, LMP2, GTD Pro, GTD
- Highlights: Daytona 24 Hours (January), Sebring 12 Hours (March), Petit Le Mans (October)
- Rules convergence with the WEC — many Hypercar/GTP machines are technically identical
The classes
GTP. The American counterpart to Hypercar. LMDh cars with hybrid power (Porsche 963, Cadillac V-Series.R, BMW M Hybrid V8, Acura ARX-06, Lamborghini SC63 — and from 2027 Ford).
LMP2. Spec prototypes, just like in the WEC.
GTD Pro. GT3 rules with professional drivers.
GTD. GT3 rules with a pro-am mix.
Why it matters
- Daytona. The Daytona 24 Hours in January opens the season — one of the must-watch events
- Sebring. Twelve hours on a former airfield, with the harshest asphalt in the world. One of the most honest tests of machinery in motorsport
- Petit Le Mans. Ten hours at Road Atlanta — a shorter, technically demanding take on the endurance idea
- Factory involvement. As in the WEC, the GTP field is deep and stacked
The ABXK take
IMSA is the second endurance series alongside the WEC that ABXK readers should know. If you watch Le Mans, you should watch Sebring too. Anyone following the WEC season will find many of the same drivers and similar cars in IMSA — but different circuits, a different culture, different stories.
In the 2026 calendar: Watkins Glen Six Hours, Petit Le Mans — the must-watch weekends.
IMSA in detail
In-depth articles on the rules, strategy and the Porsche programs in the series:
All champions since 2014
The complete IMSA champions list (top class) from 2014 to 2025.