How To Watch IMSA

The International Motor Sports Association came about in 2014 as a merge of the GRAND-AM series and the ALMS series. Originally, the series was started by the executive director of the Sports Car Club of America, John Bishop, his wife Peggy, and with help from Sr. of NASCAR Bill France in 1969. IMSA is the governing body of the WeatherTech SportsCar Championship as well as other smaller Championships. One of the biggest IMSA events is the Rolex 24 at Daytona, which kick-starts the WeatherTech SportsCar Championship every year.


With the 55th Rolex 24 at Daytona under a week away, here is everything you need to know about IMSA and the WeatherTech SportsCar Championship to get you ready to enjoy one of the most anticipated 24-hour races of the year.

IMSA Series

IMSA is the governing body for a few American-based sports car series, the pinnacle of which is the WeatherTech SportsCar Championship. The WeatherTech SportsCar Championship consists of racing at 12 of North America’s leading sports car venues, including Daytona International Speedway – the World Centre of Racing – Sebring, Watkins Glen, Road Atlanta, Long Beach, and Road America. The Championship holds four classes of cars: Prototype, Prototype Challenge, GT Le Mans, and GT Daytona.

Alongside the WeatherTech SportsCar Championship, smaller series run inside the governing body of IMSA as support series to the WeatherTech SportsCar Championship. The Continental Tire SportsCar Challenge is one that runs in tandem with the WeatherTech SportsCar Championship; they share ten rounds. The cars that race in the Continental Tire SportsCar Challenge are “showroom to speedway” cars, meaning that modifications are limited to the areas of safety and competition. The series showcases the latest in American-made and imported high-performance sports cars, coupes, and sedans. Two classes of cars participate in this series: Grand Sport and Street Tuner.

The IMSA Prototype Challenge presented by Mazda sees open cockpit ELAN prototypes with Mazda power go head to head on the racetrack. The series allows for semi-professional drivers to compete in a world-class environment, giving them an experience of the pressure racing on a world stage with Lites 1 and Lites 2 classes. Some of the rounds of the IMSA Prototype Challenge presented by Mazda are raced with the WeatherTech SportsCar Championship.

The rest of the series within IMSA are ran by manufacturers in an attempt to give up and coming drivers some experience in their sports cars and sports car racing before they progress into the higher series like WeatherTech SportsCar Championship. The Porsche GT3 Cup Challenge USA by Yokohama was put together so young and upcoming drivers and veteran semi-professionals could race together. This allows the younger drivers to take on the experience and knowledge of their older competitors. They race iconic Porsche 911 GT3 Cup car for the entire series, competing in the Platinum or Gold Cup. A Master Championship is also raced for those drivers who are over the age of 45, but they may also compete in the Platinum Cup. Each of the eight weekends in the series contains two 45-minute races on North American circuits.

The Porsche GT3 Cup Challenge Canada runs by the exact same rules as it’s American counterpart (above). Instead of being hosted on North American race circuits it allows those drivers based in Canada the chance to compete on some of the best Canadian sports car racetracks. This too consists of eight race weekends of two 45-minute races.

One of the three Super Trofeo North American series, Lamborghini Super Turbo, is also governed by IMSA. It gives race experience to rookie professional and amateur drivers in 620-HP Huracan Super Trofeo LP 620-2, the first purpose-built racing Lamborghini. There is six race meets in a season of Lamborghini Super Turbo, with each meet consisting of two 50-minute races.

Finally, IMSA has the Ferrari Challenge. This is a single model championship for Ferrari clients with a passion for racing. The series started in 1993 in a way to allow those customers of Ferrari to race against each other. The series has Gentlemen drivers rather than professional race drivers and is not usually a feeder series into higher IMSA series.

For 2017, the WeatherTech SportsCar Championship has 12 rounds, starting at the end of January and ending at the beginning of October. Half of the rounds have a duration of 2h40m, making this the standard race duration in the series. Two events have a shorter time of 1h40m, whilst the other four rounds stand out as special events with much longer race durations. The longest race is the Rolex 24 at Daytona, which is also the opening race of the series.

There are four test sessions in the season, with three of those focusing on the Rolex 24 at Daytona. Every class of car participates in each of the tests, apart from the Prototype Challenge, which does not appear in the second test at Daytona International Speedway. Below is the full season calendar for the 2017 WeatherTech SportsCar Championship, including the four test sessions.





November 15/16 2016


Daytona International Speedway


December 13/14 2016


Daytona International Speedway


January 6-8 2017

Roar Before Rolex 24

Daytona International Speedway


January 26-29 2017

Rolex 24 at Daytona

Daytona International Speedway

24 Hours

February 23/24 2017


Sebring International Raceway


March 15-18 2017

Mobil 1 12 Hours of Sebring

Sebring International Raceway

12 Hours

April 7-8 2017

BUBBA Burger SportsCar Grand Prix

Long Beach Street Circuit


May 5-7 2017

Circuit of the Americas

Circuit of the Americas


June 2-3 2017

Chevrolet Belle Isle Detroit Grand Prix

Raceway at Belle Isle Park


June 30 – July 2 2017

Sahlen’s 6 Hours of The Glen

Watkins Glen International

6 Hours

July 7-9 2017

Mobil 1 SportsCar Grand Prix

Canadian Tire Motorsport Park


July 21/21 2017

IMSA WeatherTech Northeast Grand Prix

Lime Rock Park


August 4-6 2017

Continental Tire Road Race Showcase

Road America


August 25-27 2017

Michelin GT Challenge

Virginia International Raceway


September 22-24 2017

Continental Tire Monterey Grand Prix

Mazda Raceway Laguna Seca


October 5-7 2017

Petit Le Mans

Road Atlanta

10 Hours


Race Format

The races see the grid complete formation laps before a rolling start. All four classes race on the track together but for some of the rounds, only a selection of the classes participates. Only the GT Le Mans and GT Daytona classes race IMSA WeatherTech Northeast Grand Prix and the Michelin GT Challenge. The Prototype Challenge class does not take part in the BUBBA Burger SportsCar Grand Prix or the Continental Tire Monterey Grand Prix, meaning this class’s season is only eight races long. Only the GT Daytona class completes a full 12-race season as the GT Le Mans cars do not take part in the Chevrolet Belle Isle Detroit Grand Prix.

Qualifying takes place in four 15-minute blocks, with each class having the track to themselves during their qualifying session. Only one driver qualifies for the car, with the fastest in each class taking the class pole position. The grid is organised class by class; Prototypes lead the field as Prototype Challenge, GT Le Mans, and GT Daytona line up behind them.

The Championship

In the WeatherTech SportsCar Championship, there are three titles for each team to fight for. Both a Driver’s title and a Team title is available in every class, with a manufacturers title also available for the Prototype, GT Le Mans, and GT Daytona classes. Last year, the Prototype Driver Championship was taken by Dane Cameron and Eric Curran; an all-American line-up for Action Express Racing in a Coyote Corvette DP Chevrolet 5.5l V8. They did the double by also taking the Team Championship for Action Express Racing. The pair return again to try and retain their title, but with the Daytona Prototype regulations changes, this year they will be fielding a Dallara-based Cadillac Dpi-VR 6.2L V8. Chevrolet took the Manufacturers Championship for the Prototype Class, beating Honda by 14 points.

In the Prototype Challenge, it was Alex Popow and Renger van de Zande who took the 2016 Drivers Championship. They fielded a Starworks Motorsport ORECA FLM 09 powered by a Chevrolet SL3 6.2L V8 that also took the Team Championship. This year, Zande progresses up to the Prototype class and will race a full season for VISIT FLORIDA alongside Marc Goossens whilst Popow stays another season with Starworks Motorsport.

GT Le Mans saw Oliver Gavin and Tommy Milner take the Driver Championship, driving in a Chevrolet Corvette C7.R 5.5L V8 whilst also taking the Team Championship for the #4 Corvette Racing. Chevrolet claimed two of the three Manufacturer’s Titles by also taking the GT Le Mans Manufacturer’s Championship. Gavin and Milner continue on as a winning pairing for Corvette Racing in GT Le Mans this year and hope to retain their 2016 Titles.

It was Alessandro Balzan and Christina Nielsen who took the Drivers Championship for GT Daytona. They raced the Scuderia Corsa #63 Ferrari 458 GT3 and also won the Team Championship for them. Both drivers stay on for Scuderia Corsa in 2017 and are joined by Sam Bird and Matteo Cressoni for the Rolex 24 at Daytona. However, it was Audi who took the Manufacturer’s title in the GT Daytona Class. Chevrolet, who won the other two Manufacturer’s Title, were not competing in this class.


Points are scored at the finish of each race for all cars that classify. The points system can be seen below; with all cars up to position 30 receiving points for finish the race. On top of this, ‘starting points’ are awarded to drivers and teams that start the race.


For drivers, points are only awarded if they complete the minimum required drive time that is assigned at the beginning of each race. All drivers to successfully complete their minimum driver time receive full points depending on where they finish, as well as a ‘starting point’.

For the Teams Championship, the points are handed out in the same way as they are for the Drivers Championship. The top 30 in each class gets points assigned as above and every car gets a ‘starting point’. The Team Championships sees each car as a separate competitor even if there are two cars racing for the same team.

Manufacturer’s points are assigned differently. There are no ‘starting points’ assigned for the Manufacturer’s Championships, only the point scoring system indicated above. For the Manufacturers Championship, the manufacturer only scores points from their highest finishing car. For example, if an Audi finishes first, third, and fifth, Audi will only take points for their first-place car. This means that potentially, a manufacturer can have their highest car finish fourth but still get second-place points in the Manufacturer’s Championship because the top three are all from the same manufacturer.

Pit Stops

The rules of a pit stop in IMSA and WeatherTech SportsCar events are consistent irrelevant to where the race is taking place. No mechanics or crew are allowed over the wall until the car comes to a complete stop. Once the pit stop begins, four mechanics are allowed to the car to work on refueling the cars and changing the tyres. Damage repair, changing brake pads and rotors, and wing adjustments are also done inside pit stops for the longer endurance races. The 60kph speed limit down the pit lane is enforced strictly and any drivers caught speeding down the pit lane will be handed a drive-through penalty.

Car Classes

Four classes of cars race in the WeatherTech SportsCar Championship: Prototype, Prototype Challenge, GT Le Mans and GT Daytona. For full season entry, most teams run a two driver line-up, with additional drivers joining the teams for the longer endurance races like the Rolex 24 at Daytona. At least two drivers must be in every car for every event to be allowed to compete.



The Prototype class has taken on a big regulations change for this year, with the 14-year running Daytona Prototypes being replaced with the Daytona Prototype Internationals (DPi). Along with the DPis, LMP2 cars from the World Endurance Championship can take part in this class. This class features the most technologically advanced and fastest cars in North America. These cars are designed for track racing and look a lot different to road cars.

Cars in this class have a top speed of 200mph with 600 brake horsepower. Racing in this class will be Mazda DPi, Cadillac DPi, Nissan DPi, Ligier LMP2, Multimatic-Riley LMP2, Oreca LMP2, and Dallara LMP2, powered by either a Gibson V8, Mazda 4-cylinder turbo, Cadillac 6.2L V8, or a Nissan V6 Turbo.

Prototype Challenge


In the Prototype Challenge class, every entry races the same car. This year, the car will be an ORECA FLM09 chassis powered by a Chevrolet LS3. The cars are open cockpit with a top speed of 185mph and 485 brake horsepower. Five cars have confirmed to be racing in this category for the Rolex 24 at Daytona, with only two of those signing up, so far, to complete the full season.

GT Le Mans


The cars in GT Le Mans are based on production models and modified to extract ultimate performance. Because of this, they are the fastest GTs available on the track. These are of the specification as the GTLM cars that race in the World Endurance Championship. Last year saw the #98 Aston Martin take part in the first two WeatherTech SportsCar Championship rounds as well as a full season of WEC. GT Le Mans is a good proving ground for manufacturers to trial their new GT cars directly competing against their sales rivals.

With a top speed of 180mph and 500 brake horsepower, the GT Le Mans have the same speed as the GT Daytona cars (see below) so the two categories could be racing close together in race sessions. The cars available to teams in this category are: Aston Martin Vantage V8 with an Aston Martin V8, BMW M6 GTLM powered by a BMW V8 Turbo, Corvette C7.R GTE running a 5.5L Chevrolet Pushrod 2-Valve, Ferrari 488 GTE with a Ferrari V8 Turbo, Ford GT GTE powered by a Ford EcoBoost Turbo, or Porsche 911 RSR GTE running a Porsche Flat 6.

GT Daytona


This class of cars has enhanced technology on board. Although very similar, the GTDs are not as powerful or aerodynamically advanced as the GTLM cars. These cars can have up to 500 brake horsepower but not exceeding but still run the same top speed as the GTLMs. In this class, the cars are all of an FIA-GT3 specifications regulation.

The cars on this field will consist of: Acura NSX GT3s, Aston Martin Vantage GT3s, Audi R8 LMS GT3s, BMW M6 GT3s, Ferrari 488 GT3s, Lamborghini Huracan GT3s, Lexus RF GT3s, Mercedes AMG-GT3s, Nissan GT3-Rs, and Porsche 911 GT3-Rs. The corresponding engines will be used in each make of car: Acura V6 Turbo, Aston Martin V12, Audi 5.2L V10, BMW V8 Turbo, Ferrari V8 Turbo, Lamborghini 5.2L V10, Lexus 5.0L V8, Mercedes 6.2L V8, and Porsche 4.0L Flat 6.

Number System

The number system on the cars allows fans to easily determine whether the driver line-up is a Pro line up or a Pro-Am one. It also lets spectators see where the cars are in their respective classes. A Pro line up usually consists of only professional race drivers, whereas Pro-Am is a professional and an amateur combination.

The position of a car in their respective class is indicated with a LED number at the rear of the car. This will change throughout the race so fans car see what the position of the car is within its class. The colour of the LED number on the cars corresponds with the type of driver line up racing. A red number indicates a Pro line up whilst green is for Pro-Am. These colours also appear on the wing mirrors, race number panel, windscreen banner, rear wing end plate, and the class decal.