NASCAR’s new high drag package gets its second shakedown of the season this weekend as Sprint Cup Series teams return to Michigan International Speedway for Sunday’s running of the Pure Michigan 400.

The rules configuration debuted last month at Indianapolis Motor Speedway and produced mixed results. While much data was accumulated, the competition on the relatively flat, 2.5-mile track appeared to be generally unaffected by the changes.

Changes included a 9-inch spoiler on the rear deck (increased from six inches) with a 1-inch wicker bill; a rear fascia extension panel similar to those used for superspeedway events, a 2-inch leading edge on the splitter and a 43-inch splitter extension panel (radiator pan).

“The original (aero) package … was for Michigan; we had built this package specifically for Michigan and then worked to implement it into Indianapolis,” Steve O’Donnell, Executive Vice President and Chief Racing Development Officer for NASCAR, told NASCAR.com on Tuesday. “We feel comfortable with the package we have set up … but we certainly learned some things at Indy.

“If we can improve the car in a more efficient manner, then we’re going to do that. We’ve talked to teams about what gear ratio should be implemented, and we’ll have some adjustments potentially for Michigan, and then that dialogue will continue Friday (at the track).”

Four-time Sprint Cup Series champion Jeff Gordon expects the combination of speed and less front-end downforce on a trailing car, created by the taller spoiler on the lead car, to create excitement as well as uncertainty.

“I can promise you if you get in the corner behind somebody it’s going to be a white knuckle experience,” the Hendrick Motorsports driver said. “It was at Indy so I know it’s really going to be one at Michigan. You are going to be really searching for clean air.”

Gordon called the aero package “great if you are in a straight line.”

“It offers some really cool drafting opportunities and if you have some momentum that you carry off the corner it’s really cool,” he said. “As soon as you get behind a car and you need downforce, it takes it all away.

“A big wide track like Michigan, as long as we can get away from the cars in the corners I think that it has the potential to create that big draft and momentum down the straightaways which is what we are all hoping for.”

Former series champ Brad Keselowski said cars will need to be “staggered” to run different racing grooves through the turns at MIS “to try to keep your downforce in the corner when you need it to keep the car going through the corner as fast as possible.”

“At Indy,” the Team Penske driver said, “you don’t have a lot of width to really pull that off, but at Michigan I think there’s quite a bit more width to the track, especially down in Turns 3 and 4 to where you could possibly pull that maneuver off.”

Ray Evernham, the former crew chief who helped guide Gordon to three of his four titles, said the narrow racing groove and tighter corner radius at Indy led to more off throttle time but presented less room to make a move. At Michigan, “it’s multiple grooves and pretty wide.

“So I think they’ll get more of the passing they’re looking for,” he said.

Evernham said he doesn’t believe the current configuration is a “fix-all” as officials seek to dial in different aero packages for several venues hosting Sprint Cup Series events.

“I understand they have to have drag to keep the cars from running 200-plus mph and flying through the air, but I think if you take enough downforce off them they’re not going to be going that fast anyway no matter how big or how fast the motors are,” he said.

“You’ve got to have drag. I get that. But, if you can’t get to that throttle, you’re not going to use that … horsepower. I would like to see them continue to take more out. I think these guys are spending a lot of time and I know a lot of money doing nothing but wind tunnel and CFD and I just don’t think that’s healthy for the sport.”

NASCAR also debuted a low downforce package earlier this month at Kentucky Speedway. That package is scheduled to be used once more this year — when the Sprint Cup Series travels to Darlington (S.C.) Raceway for next month’s BoJangles’ Southern 500.

Neither the high drag nor new low downforce package is currently scheduled for use in any of this season’s final 10 races that make up the Chase for the Sprint Cup.

Goodyear: Same for Cup but NCWTS gets a tweak

Goodyear officials say the same tire combination used earlier this year at MIS will be used this weekend in the Sprint Cup Series. It will be just the second time this particular right-side tire has been provided at the 2-mile track.

Competitors in the Camping World Truck Series will see a change in the right-side tire, which should improve wear. It is the same combination used earlier this season at Kansas Speedway.

At Mid-Ohio, site of the Nationwide Children’s Hospital 200, XFINITY Series teams will use the same build of tire used there since 2013. The tire was also used this past weekend at Watkins Glen and will be used when the series travels to Road America later this month.

Wet weather tires will also be provided in case of inclement weather at Mid-Ohio, one of three road-course venues on which XFINITY Series teams will be competing during a four-week span.