Updated

Welcome to the next round of Gen-Six testing.

Weather permitting, dozens of NASCAR teams will put the new Gen-Six Sprint Cup cars through hours of testing at Charlotte Motor Speedway today and Friday.

Testing is scheduled from 9 a.m. to noon ET, and 1 to 4 p.m. each day.

Today’s schedule, however, could be impacted by weather. A near 100 percent chance of rain is predicted in the speedway area.

Almost 40 Cup teams tested the new cars for portions of three days last week at Daytona International Speedway.

NASCAR and many of the participating drivers expressed satisfaction with the performance of the new cars on the 2.5-mile surface, where drafting speeds approached 200 miles per hour.

Trevor Bayne had the top drafting speed of 199.650 miles per hour. Greg Biffle had the fastest single-car run at 194.936.

This week’s Charlotte tests will be dramatically different as teams attempt to fine-tune the new cars on a surface similar to many that will be on the seasonal schedule. CMS also hosted testing in December.

More than 30 cars are expected during the two-day test. Among the teams expected to participate are Earnhardt Ganassi Racing, Hendrick Motorsports, Joe Gibbs Racing, Michael Waltrip Racing, Penske Racing, Richard Childress Racing, Richard Petty Motorsports, Roush Fenway Racing and Stewart-Haas Racing.

Mike Hembree is NASCAR Editor for SPEED.com and has been covering motorsports for 31 years. He is a six-time winner of the National Motorsports Press Association Writer of the Year Award.