The fourth round of the IMSA WeatherTech SportsCar Championship headlines the action Friday through Sunday at Road America, the 4.048-mile road course in Elkhart Lake.

Also on track are the IMSA Protytype Challenge, Porsche GT3 Cup and Michelin Pilot Challenge. The Midwest Council of Sports Car Clubs has a Spec Miata test day Thursday and concludes the weekend with its race Sunday.

RELATED: Weekend schedule

Here’s what you need to know about the IMSA SportsCar Weekend main event:

Nuts and bolts

When: 11:05 a.m. Sunday. Qualifying is from 1:50-2:55 p.m. Saturday in three 15-minute sessions by class.

Broadcasts: Live on NBC television, Sirius satellite radio channel 219, XM 202.

Length:  2 hours 40 minutes timed.

2019 winners: DPi – Jonathan Bomarito/Harry Tincknell, No. 55 Team Joest Mazda; LMP2 – Matt McMurry / Patrick Kelly, No. 52 PR1/Mathiasen Motorsports ORECA; GTLM – Ryan Briscoe / Richard Westbrook, No. 67 Ford GT; GTD – Matt Campbell / Zacharie Robichon, No. 9 Pfaff Motorsports Porsche 911 GT3 R.

Five storylines

Feel-good story: A little case of COVID-19 couldn’t keep Felipe Nasr down for long. After missing the July 4 race due to his positive coronavirus test, he returned for the most recent race two weeks ago and teamed with Pipo Derani for the overall victory in Sebring, Florida.

Same winner, different division: Ryan Briscoe is going for three straight victories at the track but technically isn’t a defending winner, given his 2018 and ’19 victories came in a different class (GT Le Mans) with a team that no longer exists (Chip Ganassi’s factory Ford program). On the other hand, Briscoe is in the fight for the overall race win these days. He and Renger van der Zande lead the DPi standings for Wayne Taylor Racing on the strength of a Daytona 24 Hours victory and Sebring…