IMSA - Detroit

The Detroit IMSA race returns to the streets of downtown Detroit as part of the Chevrolet Detroit Grand Prix presented by Lear. This street circuit event brings the IMSA WeatherTech SportsCar Championship to a 1.7-mile, nine-turn course that winds through the city. The Detroit Street Circuit features well-traveled downtown roads and provides a challenging urban racing environment for multiple prototype and GT classes.

Detroit Street Circuit Layout

The Detroit Street Circuit measures 1.7 miles and contains nine turns. The track uses Jefferson Avenue, Bates Street, Atwater Street, St. Antoine, Franklin Street, and Rivard. Cars navigate elevation changes throughout the lap, creating a demanding test of driver skill and car setup.

The circuit features a long 0.7-mile front stretch on Jefferson Avenue where cars reach high speeds before braking for turn one. Turn three presents a wide hairpin that challenges drivers to find the optimal line. Bates Street drops down toward the Detroit River, creating a fast downhill section. The backstretch runs along Atwater Street with a sweeping left-hand corner. Franklin Street contains a unique double-sided pit lane configuration. Rivard provides a narrow, uphill challenge as drivers complete the lap.

IMSA WeatherTech SportsCar Championship Race

The IMSA race at Detroit runs for 100 minutes. Four classes compete together on track: Grand Touring Prototype (GTP), GT Daytona Pro (GTD PRO), Le Mans Prototype 2 (LMP2), and GT Daytona (GTD). Each class battles for position while managing traffic from faster and slower categories.

Competition Classes

The GTP class features the fastest cars with LMDh specifications. These hybrid prototypes from manufacturers like Acura, Cadillac, Porsche, and BMW represent the top level of IMSA competition. GTD PRO teams field professional driver lineups in GT3-specification cars from Ford, Corvette, Porsche, and other manufacturers. The LMP2 class runs spec chassis from Oreca and other approved constructors. GTD allows a mix of professional and amateur drivers in the same GT3 machinery used in GTD PRO.

Teams and Drivers

Major IMSA teams compete at Detroit. Wayne Taylor Racing Andretti, Porsche Penske Motorsport, Meyer Shank Racing, and Ford Multimatic Motorsports field entries across multiple classes. The driver roster includes experienced sports car racers who understand the demands of street circuit racing.

Teams must adapt their setups for the Detroit Street Circuit. The concrete walls leave no margin for error. Brake wear becomes critical over the race distance. Suspension settings must balance the need for kerb riding with the demands of elevation changes. Tire management plays a key role as the abrasive street surface creates degradation.

Technical Regulations

IMSA enforces strict technical regulations for the WeatherTech SportsCar Championship. The rules include the "Short FCY" protocol for managing caution periods. Bronze-rated drivers in GTP and GTD PRO must meet minimum drive time requirements similar to those in LMP2 and GTD. IMSA publishes Technical Bulletins to modify regulations as needed throughout the season.

LMDh cars follow specific technical rules that balance performance across different manufacturer chassis and engine combinations. Michelin provides tires for all competitors. Teams may need to share tire performance data with IMSA officials. These regulations ensure close competition across all classes.

History of Racing in Detroit

Detroit has a long history of street circuit racing. The original Detroit Grand Prix street circuit opened in 1982 and measured 2.5 miles. Formula One raced there from 1982 through 1988, then CART took over from 1989 to 1991. That circuit was known for punishing brakes and gearboxes. Drivers like John Watson, Ayrton Senna, Emerson Fittipaldi, and Michael Andretti won races on Detroit streets.

The Grand Prix moved to Belle Isle Park in 1992 and remained there for decades. The event returned to downtown streets in 2023 on a new circuit layout. This brought racing back to the urban core and created new opportunities for fan access.

Event Impact and Atmosphere

The Detroit Grand Prix generates significant economic activity. The three-day weekend attracts over 150,000 people to downtown Detroit. Regional spending associated with the event exceeds $100 million annually. The race weekend includes the IMSA WeatherTech SportsCar Championship alongside the NTT IndyCar Series and Indy NXT by Firestone.

The downtown location provides fans with close access to the action. Temporary grandstands line the circuit at key viewing locations. Fans can walk the paddock area and see teams prepare the cars. The urban setting creates a festival atmosphere throughout the race weekend. The event has a contract to remain downtown through 2028, securing its place on the calendar.

What Makes Detroit Special

Street circuits present unique challenges compared to permanent road courses. The Detroit Street Circuit offers no runoff areas. Drivers must commit fully to each corner knowing that contact with a wall ends their race. The varying grip levels on street surfaces require constant adaptation. Morning sessions see lower grip that improves as rubber builds up throughout the weekend.

The 100-minute race duration creates strategic decisions. Teams must choose between fuel saving and pushing for position. Yellow flags can shuffle the running order and change strategy calculations. The multi-class format means GTP leaders navigate through GT traffic while GTD cars battle among themselves while being overtaken by faster prototypes.

Detroit represents one of the few true street circuits on the IMSA calendar. The combination of high speeds on Jefferson Avenue and tight sections on Rivard tests every aspect of car performance. Teams that optimize their setup for this unique venue can gain a competitive advantage. The race rewards precision driving and smart race management over raw speed alone.