NASCAR vs IMSA: The Main Differences

NASCAR is one of America’s most popular racing series, but it has competition. And despite having ties to IMSA, the sports car organization is a major competitor. But new motorsport fans may wonder about the differences between NASCAR and IMSA.

NASCAR and IMSA differ in almost all respects, and everything varies between them, from the cars to the types of tracks, and from the speeds to the racing formats. IMSA also has many more manufacturers and classes present than the 3 you see in NASCAR, even though NASCAR owns IMSA. 

Below, we will outline NASCAR’s relationship to IMSA, before comparing the series’ respective cars, tracks, drivers, teams, and racing. We will also reveal which series has the faster cars, along with some characteristics the two divisions have in common.


NASCAR does own IMSA and has done since 2012. The two series are very different, but they have had ties since IMSA was created back in 1969. While NASCAR owns IMSA, they are run as two completely separate racing series.

IMSA is part of Speedweeks and if you ever heard of the Rolex 24 At Daytona, also known as the 24 Hours at Daytona, then you know of at least one IMSA race. Several NASCAR drivers have competed in the sports car race, while road course ringers like Scott Pruett and Juan Pablo Montoya have won races there. 

IMSA’s relationship with NASCAR dates back to its founding, when Bill France Sr. helped John Bishop get the series off the ground. The series ran independently from NASCAR until 2012, following a series of transitions that started in 1989 when John and Peggy Bishop decided to sell the series. Subsequent sales came in 1994 and 1996 before Don Panoz bought the series in 1999. 

Panoz sold the series to NASCAR in 2012, and the sanctioning body unified the series and the Grand-AM sports-car series. This led to the IMSA Tudor United SportsCar Championship, which debuted in 2014. Today, the series is known as the IMSA SportsCar Championship. 

In-Depth Timeline Of Events

Bill France Sr. expanded NASCAR to dominate the oval circuit scene, leading him to generate an interest in road racing. John Bishop was an employee for the Sports Car Club of America (SCCA), but clashes with management led him to seek opportunity elsewhere, and he ultimately teamed up with France. 

Following a slow start, France and Bishop managed to convince investors to buy into the new series, and by the mid-1970s, it developed into a popular racing series. Health issues starting in 1987 forced Bishop to sell to CP Ventures in 1989, headed up by Mark Cone and Jeff Parker. And in 1994, they wanted out and sold the series to Charlie Slater. 

IMSA struggled under Slater, and he sold to the International Motorsports Group (IMG), where it became known as Professional SportsCar Racing. During this time, Bishop hopped back into the road racing business, this time with Bill France Jr. They, and several others, revived the United States Road Racing Championship, giving serious competition to the series from 1998 to 1999.

Don Panoz stepped in, bought the series, and changed the name to American Le Mans. At this point, Jim France and NASCAR created the Grand-Am Series. Each series grew, and the two series finally saw their merger occur in 2012, taking on the IMSA name and a new series debuted in 2014, which has grown substantially ever since. 

NASCAR vs IMSA: The Cars

Manufacturers318 (across all 6 classes)
Horsepower510-670 HP300-600 HP
EnginesV8 NAV6-V12

When you take just one look at NASCAR and the many varieties of IMSA cars, you can tell they are different breeds. Even with NASCAR’s Next Gen car being introduced in 2022, each ride contains major differences since they are built to race on different types of tracks


NASCAR Next Gen cars look completely different from their Generation 6 predecessors. They feature 18-inch wheels, V8 naturally aspirated pushrod engines targeting 670 horsepower (510 horsepower at superspeedways and Atlanta) with 358 cubic inches (5.9 liters) of displacement. 

The Next Gen cars have an independent rear suspension with dual exhaust pipes near the doors, and five-speed sequential manual transmission. The cars also further resemble their showcase counterparts, giving them more of a stock car look. They take Sunoco Green E15 Racing Fuel, and like their predecessors, they use Goodyear tires, and a chassis featuring a steel frame and roll cage. 

The cars also have a 110-inch (279 cm) wheelbase, 193-inch (491 cm) length, 79-inch (200 cm) width, and 50-inch (128 cm) height. They vary weight-wise because of driver weight, but the baseline sits at 3,200 lb (1,450 kg) for a 180 lb (82 kg) driver without fuel or the driver, and 3,400 lb (1,540 kg) with the driver and fuel. 

The Next Gen cars also shed much of their older technologies that had been staples for much of the previous generations. The truck arms, Saginaw steering, and four-speed gearbox are gone, as are the 15-inch wheels. The Next Gen car’s wheels are aluminum instead of steel, and they require just one lug nut instead of five. 

IMSA Cars – Prototype Category

Unlike NASCAR, IMSA cars fall into one of six different classes (including the Michelin Pilot Challenge), with the Daytona Prototype International (DPi) comprising the first. Like the Next Gen cars, they are built for sportscar racing only, featuring the latest technologies. Engine designs vary by manufacturer, but they all target 600 horsepower, featuring six-speed sequential transmission. 

NOTE: The Michelin Pilot Challenge is a support series for IMSA’s higher classes

They use Michelin tires, and the DPi class can choose between hard and medium compounds. The Le Mans Prototype 2 (LMP2) clocks in beyond the DPi, and one striking difference between LMP2 and DPi is that the engines in the LMP2 class feature 4.2 liter (256 cubic inches), targeting 560 horsepower. Like DPi, these cars weigh 2,000 lb (909 kg), but they run at slower speeds. 

LMP2 cars use the same tires as DPi. LMP3 is the next one down the rung, and their Nissan V8 engines target just 455 horsepower. LMP3 is the lowest in the Prototype Category. 

IMSA Cars – Grand Touring Classes

The Grand Touring Daytona Pro (GTD Pro) is the top car in the Grand Touring Category, and like the NASCAR Next Gen, it saw its first season in 2022. This category replaced the GT Le Mans (GTLM), and its specs are identical to the lower Grand Touring Series Class, the GTD. 

The engines in both classes also come in a variety, each taken from production lines and modified. They range in displacement and between V8 and V10. However, they often target 500 hp. 

IMSA Cars – Michelin Pilot Challenge

The Pilot Challenge cars come in two forms: the Grand Sport (GS) and Street Tuner (ST) classes. The former range in cylinder setup from 6 to 12, while the ST class uses 4, 5 or 6-cylinder vehicles. These vehicles offer a range of power outputs and top speeds.

Are NASCAR Cars Faster Than IMSA Cars?

NASCAR cars are faster than some IMSA cars, but not all of them. While a NASCAR Cup car will reach a top speed of close to 200 mph, IMSA prototype cars can reach similar speeds if not faster. However, the LMP3 class in IMSA will only reach about 185 mph, with the lower classes being slower still.

One important thing to remember when comparing NASCAR cars with IMSA cars is that NASCAR’s Next Gen car did not focus on speed as much as it did to create closer racing. Next Gen cars are often slower than their predecessor, the Gen 6, so keep this in mind when we compare speeds between NASCAR and IMSA cars. 

Since IMSA races in five different classes, we also need to keep this in mind when we compare the speeds. The NASCAR Next Gen car saw its top practice speeds for the 2022 Daytona 500 clock in at a speed of 192 mph (309 kph). However, DPi cars can hit the 200 mph (322 kph) mark at larger tracks

The Generation 6 car’s top speed reached 199 mph (321 kph), putting it within striking distance of the DPi. While you will see that some cars in the lower classes rival the Next Gen, none of them match the Generation 6’s top speed. 

The Lower Classes 

LMP2 cars run around the same pace as the NASCAR cars, but slower than the DPi cars at 190 mph (306 kph). The Next Gen cars, however, can reach higher speeds with draft help at superspeedways, having reached 194 mph (312 kph) when running test sessions during Speedweeks. 

LMP3 cars are slower than the Next Gen, coming in at 185 mph (298 kph), while the Grand Touring cars are significantly slower, with top speeds hovering around 182 mph (293 kph). 

NASCAR vs IMSA: The Tracks

Track Types22 Ovals / 5 Road Courses / 1 Street Circuit10 Road Courses / 1 Street Circuit
Races36 (points)11 
Season Length10 months10 months

When you look at NASCAR’s schedule and IMSA’s schedule, you will notice dramatic differences in the tracks they race on. NASCAR has long raced on oval tracks, although they will race on the occasional road course and, starting in 2023, the Streets of Chicago. NASCAR and IMSA tracks are not as dramatically different as they used to be, but a discrepancy continues to exist. 

Some Tracks They Have In Common

However, the two series have a few tracks in common, with the most popular being the Daytona International Speedway. As part of Speedweeks, IMSA’s 24 Hours At Daytona kicks off its respective season and it is one of the most grueling endurance races in the world. However, while NASCAR races on Daytona’s oval, IMSA uses the sports car course layout

IMSA and NASCAR also both race at Watkins Glen and, until NASCAR scheduled the Chicago Street Race, Road America. The NASCAR Truck Series and ARCA share one track with IMSA: the Mid-Ohio Sports Car Course. IMSA races on road courses located all over the United States and one track in Ontario, Canada. 

NASCAR’s Tracks

In recent seasons, NASCAR has seen an influx of road courses that include the Chicago Street Course, the Sonoma Raceway, Charlotte Roval, Watkins Glen International, Indianapolis Motor Speedway Road Course, and Circuit of the Americas (COTA). 

They also predominantly race on oval tracks that vary between superspeedways, intermediate ovals, and short ovals. Daytona, Pocono, and Talladega comprise the superspeedways. Intermediate tracks comprise most of the NASCAR circuit. Pocono is not often included as a superspeedway, but NASCAR’s official website does classify the 2.5-mile (4 km) triangle as such. 

Like road courses, NASCAR’s list of short tracks is growing, with the Los Angeles Memorial Coliseum and North Wilkesboro joining or rejoining the roster for 2022 and 2023. Other short tracks include Bristol, Martinsville, and Richmond. 

NASCAR Sees More Tracks

IMSA is a lot like Formula 1 in terms of tracks, racing only on road courses and running just a fraction of the number of events that NASCAR runs. They run at just 11 tracks, compared to the NASCAR Cup Series planning to visit 28 different tracks in 2023. IMSA’s 2023 season length caps at 11 races while NASCAR runs 36 points-paying races and three non-points-paying events. 

NASCAR vs IMSA: Drivers & Teams

If there is one thing to know about IMSA, it is that they run substantially more manufacturers than NASCAR. While NASCAR only runs three: Chevrolet, Ford, and Toyota, you can see up to 20 different makes of cars at IMSA events. NASCAR also has 17 full time teams, with 36 cars with charters (meaning they are guaranteed a starting spot in the field). 

IMSA can see dozens of teams competing across the 6 classes. Since IMSA runs many endurance races, you will also notice that a team can have several drivers. For example, the winners at the 2022 Sebring race’s DPi class comprised three different drivers while the winning team at the 2022 24 Hours at Daytona had four different drivers. 

While you will see NASCAR swap drivers at special times during an event, this often is not the case since the races can be significantly shorter. However, even at shorter IMSA events, you will also see driver swaps. The shorter Grand Prix of Long Beach event saw two drivers per team, despite the race lasting for just one hour and 40 minutes. 

IMSA Teams And Drivers Go International

Many of the drivers you see in the NASCAR Cup Series also come predominantly from the United States, though there have been many exceptions in the past and present. IMSA carries more of an international flair, with five of the seven continents represented in 2022. 

The teams also come from all over the globe, with countries like Denmark, the United Kingdom, the Netherlands, Russia, Belgium, Canada, Germany, Italy, and Australia represented. Most of the variety occurs in the Grand Touring classes, though the LMP2 and LMP3 classes also see a fair share of diverse nations. 

As mentioned, IMSA also carries more manufacturers than the three you see in NASCAR. They include Acura, Cadillac, Oreca, Nissan, Porsche, Mercedes, and Lexus. If variety is something you crave when you watch auto racing, IMSA will offer it not just in their many classes, but also their manufacturers!

NASCAR vs IMSA: The Racing

NASCAR and IMSA each have dramatically different styles of racing, with variety being the name of IMSA’s game. When you look at IMSA’s schedule, you will notice they run endurance races that last between six hours (Watkins Glen) to 24 hours (Daytona). IMSA also has races that cap themselves at substantially shorter lengths, between 1 hour and 40 minutes to 2 hours and 40 minutes. 

NASCAR races last for a predetermined number of miles and they contain no real timetable. If a NASCAR race has a weather delay, the event can last for many hours, even known to persist well into the evening. Most NASCAR races that occur on oval tracks last between 300 miles (483 km) and 500 miles (805 km), but some races are much shorter or longer.

The Bristol Dirt Race lasts for 133 miles (214 km) while the Coca Cola 600, NASCAR’s version of an endurance race, goes for 600 miles (966 km). In rare cases, NASCAR will set its length to kilometers. For example, the spring Phoenix event is called the ‘Sponsor Name 500’ and is 500 km long (312 miles). 

NASCAR’s racing format has changed over the last decade with the adoption of stage racing. This implementation divides each race into three stages (four at the Coca Cola 600) and gives points to drivers who finish in the top ten at each stage. This benefits drivers who may, for one reason or another, have crashed out later in the event despite enjoying a solid run. 

One Major Difference Between NASCAR & IMSA

One huge difference between NASCAR and IMSA racing is that you will see all five classes (excludes the Pilot Challenge) racing at the same time. That would be akin to Cup Series, Xfinity, Truck, and ARCA all going at it on the same track. When you watch an IMSA race, keep in mind that there are really five classes racing all at once, so if you like controlled chaos, IMSA has it. 

You can gain a visual of what an IMSA race’s grid looks like by checking out the results of past IMSA races, where you will find five winners per race, one for each class, on the same grid. So, if the driver of an LMP3 finished the race 10th overall, they could still be a class winner if they were the first LMP3 to cross the start-finish line by the end of the event. 

In IMSA, you often see the DPi cars take the top spots in the race results, before the LMP2 cars comprise the majority of the second tier, then LMP3, and finally, the two Grand Touring classes. 

Final Thoughts

NASCAR and IMSA have some things in common, but they are primarily two very different motorsport series. Everything from the types of cars they drive to the tracks they race on is different. This is despite the fact that NASCAR owns IMSA, and has done since 2012.