Multiple races happening at once.

One of the most exciting things about IMSA is multiclass racing. Faster prototypes and production-based GT cars share the same circuit, creating constant traffic, passing opportunities and strategic decisions.

Cars compete primarily against others in their own class. A GTD car can finish behind a GTP car on the track and still win its class.

Endurance racing adds another dimension. Races can last several hours, including the iconic 24-hour race at Daytona. Drivers share cars, teams manage pit stops and fuel, and reliability is just as important as outright speed.

Fan tip: Follow the class position, not just the overall running order. There can be a battle for the lead in several classes simultaneously.

The IMSA WeatherTech SportsCar Championship is IMSA’s premier racing series, featuring purpose-built prototypes and GT race cars based on road-going models. Four classes, GTP, LMP2, GTD PRO and GTD, share the track all at once, each competing for its own win in class. Races can be as short as 100 minute sprint races to as long as full 24 hour races and everything in-between. Depending on race duration, teams may run anywhere from 2 to 4 drivers per car, with teams switching drivers during pit-stops. To win in endurance racing takes strategy, speed, teamwork, perfect execution, and the ability to navigate class traffic with grace.

Our other two premier series include the IMSA Michelin Pilot Challenge , featuring GT4 and TCR machinery, and the IMSA VP Racing SportsCar Challenge, featuring LMP3 and GT4 machinery.

Beyond our three premier series, IMSA also sanctions multiple Single-Make Series that you'll find racing with us on many IMSA race weekends in the lead-up to our premier series.

Four classes. One track. , opens in a new tab

In the IMSA WeatherTech SportsCar Championship, cars with different designs, performance characteristics and driver requirements compete simultaneously. Each class has its own competition and championship. Watch the YouTube link above to learn more!

Within the standard IMSA season, there is a championship within a championship called the Michelin Endurance Cup. This encompasses the longest and most demanding races of the year, rewarding teams that excel in extreme endurance formats. The Michelin Endurance Cup encompasses the following five races:

• Rolex 24 At Daytona: The season opener and crown jewel. A grueling 24-hour race on the high banks of Daytona International Speedway.
  
• Mobil 1 Twelve Hours of Sebring: Known as a car-breaker. The bumpy concrete runways of a former WWII airbase make this 12-hour race famously brutal.
  
• Sahlen’s Six Hours of The Glen: A high-speed, 6-hour summer classic in upstate New York at Watkins Glen International.
  
• Motul SportsCar Endurance Grand Prix: New for 2026 and beyond, this thrilling endurance challenge is set on the sprawling and historic 4-mile road course in Elkhart Lake, Wisconsin.
  
• Motul Petit Le Mans: The 10-hour season finale at Michelin Raceway Road Atlanta, where championships are decided in the dark.

It's more than just the driver. We have more than 900 each season!

IMSA brings together automotive manufacturers, independent racing teams and drivers from around the world.

Manufacturers develop and support racing programs to demonstrate performance and technology. Racing teams prepare and operate the cars, manage strategy and execute pit stops. Drivers compete across different experience levels, including professional racers and amateur-rated competitors.

In endurance races, multiple drivers share the same car, taking turns behind the wheel. Success requires teamwork, consistency and the ability to adapt to changing track conditions.

Fan tip: Pick a favorite manufacturer, car, team or driver. Following their progress throughout the season makes every race more engaging.

From racing enthusiasts to professional sports car drivers.

IMSA is more than its premier IMSA WeatherTech SportsCar Championship. Its racing ecosystem includes several series offering different types of cars, levels of competition and opportunities for driver development.

• IMSA Michelin Pilot Challenge: Production-based Grand Sport (GS) and Touring Car (TCR) race cars.

• IMSA VP Racing SportsCar Challenge: A development platform featuring prototype and GT racing.

• Single-make series: Series featuring closely matched cars from one manufacturer, including Porsche Carrera Cup, Whelen Mazda MX-5 Cup, Lamborghini Super Trofeo, McLaren Trophy America, Mustang Challenge and Ferrari Challenge.

Customer racing is an important part of this ecosystem. Manufacturers offer purpose-built race cars and support programs that allow customers and independent teams to compete.

There is no single mandatory path to the top. Drivers can develop through different championships, gain experience and progress toward higher levels of sports car racing.

The IMSA WeatherTech SportsCar Championship awards points based on class finishing position, with an emphasis on rewarding top results.

A class win is worth 350 points, second place 320 and third place 300, creating larger gaps among the leading finishers. Fourth place earns 280 points and fifth receives 260. From fifth place on back, the scale becomes more gradual, with each position separated by 10 points (250 for sixth, 240 for seventh, etc.) down to 10 points for 30th place or lower. Separate qualifying points are awarded using the same structure at 10 percent of race points, with 35 points for pole position, 32 for second and 30 for third, etc.

ALL TYPES OF POWERTRAINS

IMSA cars in the WeatherTech Championship have all different types of engine architectures. Hybrids, turbocharged, naturally aspirated, V6’s, V8’s, V10’s and V12’s all competing against each other. Because fuel consumption varies between these configurations, IMSA regulates Stint Energy instead of fuel. That’s why one standard of “fuel” measurement was needed, Stint Energy. Stint Energy is an exact measurement of how much power over time (kWh) a car can use between refuels.

STINT LENGTH IS EVERYTHING

The distance a car travels between refueling is called stint length. Keeping this equal between cars in class is essential for competitive endurance racing. The challenge is that race conditions constantly change, and so do MPG’s. A naturally aspirated V8 may get great fuel economy at race pace, but get far worse economy during yellow flag running compared to its turbocharged competitors. Stint Energy provides a more consistent way to balance performance across varying conditions.

NO FUNNY BUSINESS

Torque sensors mounted to the axles measure actual power output over time, and that data determines the Stint Energy usage. The system provides an extremely precise measurement of energy usage which helps IMSA maintain a level playing field across different manufacturers and powertrains.

STINT ENERGY

Is monitored by IMSA through the Bosch data loggers. The Stint Energy telemetry you see is a percentage of how much Energy each car has left. When cars refuel, it takes exactly 40 seconds to fill the stint energy from 0 - 100%.

ENERGY YOU CAN SEE

During pit stops, the car’s digital number panel displays the remaining Stint Energy percentage in real time.

YES — CARS CAN STILL RUN OUT OF FUEL

Bosch telemetry allows IMSA to precisely match stint energy to fuel usage. Teams need to carefully monitor both fuel loads and energy remaining, less fuel means less weight, but you don’t want to be left on track with an empty tank and 5% Stint Energy left.

Follow the action from anywhere.

IMSA offers several ways to experience sports car racing, whether you're watching at home or attending an event.

In the United States, WeatherTech Championship coverage is available through NBC Sports and Peacock, with specific coverage varying by event.

International audiences can watch IMSA racing through IMSA's official YouTube channel and IMSA.tv, subject to regional rights.

Fans can also follow live timing, live commentary, race results, race schedules and championship standings on IMSA.com. The IMSA YouTube channel offers race highlights, replays and additional content that brings fans closer to the teams and drivers.

A short reference for the terms you'll hear during a race broadcast.

Multiclass racing

Different categories of cars competing on the same track

Prototype

A purpose-built race car, rather than a race car based on a production model

GT3

A regulated category of production-based sports car racing

Stint

The period a driver or car runs between pit stops or driver changes

Full Course Yellow

A caution period affecting the entire circuit

Safety Car

A vehicle used to control the pace of the field during certain caution periods

Traffic

Cars encountering others from different classes or on different laps

Pole Position

The first starting position in a class

DNF

Did Not Finish

BoP

Balance of Performance, technical measures used to balance competition between different car models, enabling all automotive manufacturers to participate.