2018 Chevrolet Sports Car Classic

The 2018 Chevrolet Sports Car Classic was a sports car race sanctioned by the International Motor Sports Association (IMSA). The race was held at the Raceway on Belle Isle in Detroit, Michigan on June 2, 2018. The race was the fifth round of the 2018 IMSA SportsCar Championship.

Background
Similar to the Grand Prix of Long Beach, this event was held in conjunction with the Detroit Grand Prix in the IndyCar series, with one event held on the same day as the IMSA event, and another held a day after as a double-header.

International Motor Sports Association's (IMSA) president Scott Atherton confirmed the race was part of the schedule for the 2018 IMSA SportsCar Championship (IMSA SCC) in August 2017. It was the fifth consecutive year the event was held as part of the WeatherTech SportsCar Championship, and the ninth annual running of the race, counting the period between 2007 and 2013 when it was a round of the Rolex Sports Car Series and the American Le Mans Series respectively. The 2018 Chevrolet Sports Car Classic was the fifth of twelve scheduled sports car races of 2018 by IMSA, the shortest in terms of time, and was the third round not held on the held as part of the North American Endurance Cup. The race was held at the fourteen-turn 2.350 mi Belle Isle Park on June 2, 2018. After the Sports Car Challenge of Mid-Ohio three weeks earlier, Filipe Albuquerque and João Barbosa led the Prototype Drivers' Championship with 119 points, ahead of Eric Curran and Felipe Nasr with 109 points, and Jordan Taylor and Renger van der Zande with 104 points. In GTD, the Drivers' Championship was led by Bryan Sellers and Madison Snow with 95 points, ahead of Katherine Legge and Álvaro Parente with 87 points. Cadillac and Lamborghini were leading their respective Manufacturers' Championships, while Mustang Sampling Racing and Paul Miller Racing each led their own Teams' Championships.

On May 25, 2018, IMSA released the latest technical bulletin outlining Balance of performance for the GTD class. The Lexus RC F GT3 received a 25 kilogram weight increase. The Mercedes AMG GT3 received a 10 kilogram weight break. No changes made in P.

Entries
A total of 26 cars took part in the event split across two classes. 14 cars were entered in P, and 12 in GTD. In P, Spirit of Daytona Racing made their first appearance since Sebring. Performance Tech Motorsports skipped to focus on testing before the Watkins Glen round. Harry Tincknell returned to the Mazda Team Joest No. 55 entry. GTD saw a number of driver changes. Robby Foley joined Bill Auberlen in the Turner Motorsport entry while Mario Farnbacher substituted for Álvaro Parente in the Meyer Shank Racing No. 86 entry due to a clash with the Blancpain GT Series Endurance Cup round at Circuit Paul Ricard. Bernd Schneider joined Kenny Habul in the SunEnergy1 Racing entry. Jeff Segal substituted for Alessandro Balzan in the Scuderia Corsa entry due to a medical procedure.

Practice
There were two practice sessions preceding the start of the race on Saturday, two on Friday. The first ninety-minute session was on Friday morning. The second on Friday afternoon lasted 110 minutes.

Practice 1
The first practice session took place at 8:15 am ET on Friday and ended with Ricky Taylor topping the charts for Acura Team Penske, with a lap time of 1:21.909.

Practice 2
The second and final practice session took place at 1:05 pm ET on Friday and ended with Hélio Castroneves topping the charts for Acura Team Penske, with a lap time of 1:22.363.

Qualifying
Friday afternoon's 40-minute qualifying session was divided into two groups. Both categories had 15-minute individual sessions, and regulations stipulated teams to nominate a single driver to qualify their cars. The competitors' fastest lap times determined the starting order with the grid arranged to put the Prototype cars ahead of all GTD entries.

Qualifying results
Pole positions in each class are indicated in bold and by ‡.


 * The No. 44 Magnus Racing entry was moved to the back of the GTD field for starting the race with a different driver than who qualified.
 * The No. 85 JDC-Miller MotorSports entry had its two fastest laps deleted as penalty for causing a red flag during its qualifying session.

Post-race
The result kept Albuquerque and Barbosa atop the Prototype Drivers' Championship with 144 points while Nasr and Curran tied them on points. The result kept Sellers and Snow atop the GTD Drivers' Championship with 122 points. Aschenbach and Marks advanced from sixth to fourth. Cadillac and Lamborghini continued to top their respective Manufacturers' Championships while Mustang Sampling Racing, and Paul Miller Racing kept their respective advantages in the Teams' Championships with seven rounds remaining.

Results
Class winners are denoted in bold and ‡.

Standings after the race

 * Note: Only the top five positions are included for all sets of standings.


 * Note: Only the top five positions are included for all sets of standings.


 * Note: Only the top five positions are included for all sets of standings.