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Updates to the current rules package aimed at reducing both downforce and side force will be in place this weekend when NASCAR Sprint Cup Series teams travel to Charlotte Motor Speedway to compete in the Sprint Showdown and Sprint All-Star race.
According to Gene Stefanyshyn, senior vice president of innovation and racing development for the sanctioning body, three areas have been addressed with the updates. They involve truck trailing arm and crossmember assembly, electric fans used for cooling purposes on the cars and rear wheel toe alignment.
The trailing arm issue was actually addressed previously with a change put into place before the series competed earlier this month at Kansas Speedway. Teams must now weld truck trailing arm mounting brackets (and mounting tabs, if used) to prevent movement. That change will remain in place for the remainder of the 2016 season.
Stefanyshyn said the decision to reduce the number of fans was made after it was determined that some of the units "have actually been creating downforce on the car."
RELATED: Explaining the low downforce package
Limiting the number of cooling fans will provide "a good efficiency improvement as far as managing or attenuating some costs … and it also gave us a downforce reduction,” he said. "So it was a win-win. Some of those fans were driving things like bigger fans, bigger alternators, bigger batteries … that kind of thing."
Rear toe alignment changes will decrease the amount of skew (slant) allowed in a car's setup.
"We currently allow them to set up the car with some skew that provides not only a turning advantage but also a side force advantage," he said. "Usually the way a team would set that up is on the right side they take 0.6 degrees of toe out and on the left side they do about 0.3 degrees of toe in. We're going to change the specifications so it's going to be neutral; it will be zero setup. That will take some of the skew out of the car, which will take some of the side force off the car."
It is also expected to reduce corner speeds approximately 3 mph at a track such as Charlotte.
The rear toe change will be in place only for this weekend's all-star events.
"We want to see what the effect of it is," Stefanyshyn said. "The fans … we know directionally (that's) downforce off. And we know the (teams) made some back, so taking it off puts us in a good spot. Plus it's a good cost (savings). So everybody feels comfortable."
The changes are part of the evolution of the lower downforce package that debuted in mid-2015 where it was used for races at Kentucky Speedway and Darlington Raceway. It was implemented full time for the 2016 season on all tracks except Daytona International Speedway and Talladega Superspeedway.
Downforce is the pressure created across the surface of a vehicle at speed. Likewise, side force is generated by the flow of air along the sides of the vehicle.
Although teams continue to work to recover the loss of downforce with the current rules package, Stefanyshyn estimated that any gains teams have made have likely been relatively small.
"We took over 900 pounds of downforce off for this year. Some … are saying 'Well, they've gotten it all back,' " he said. "We don't believe that it's been that drastic, that they've gotten all 900 back. We're thinking it's maybe 100-200, something like that," he said.
Because the Sprint All-Star Race is a non-points event, it provides officials and teams the opportunity to observe the impact of the changes without the fear of upsetting the integrity of the regular season.
And officials at Charlotte have been behind the decision to roll out the changes during the all-star weekend.
"We really need to thank Marcus Smith here because when we do some of these things we want to make sure the tracks know the package is coming, they're supportive," Stefanyshyn said. "Marcus has been very open-minded to help us try some of these things.
"Everybody plays an important position here; we all want everybody together."
Four teams are scheduled to take part in a one-day Goodyear tire test Tuesday at Michigan International Speedway, and are expected to have the latest changes in place while also looking at possible changes to the aerodynamic package for 2017.
The 2-mile track was the site of a high downforce test last year.
Austin Dillon (Richard Childress Racing), Kyle Larson (Chip Ganassi Racing), Aric Almirola (Richard Petty Motorsports) and Martin Truex Jr. (Furniture Row Racing) are slated to participate in Tuesday's test.
"A lot of stuff we've done have not been with aero pieces on the car but they do have an aero effect," Stefanyshyn said of the latest changes. "But we are looking at other things, working on other things. We've been working on this for the last two or three years and the question on it is how do you implement it in a way that's friendly, cost-effective and all that?
"Depending on how the journey goes and what we find out, that could be something we could consider for '17. The good thing is now that we're all working closely together, we're further ahead quite a ways. So if we get to the point where we decide we want to implement, I think we do it in a very structured and calm way, not hectic … so that everybody feels comfortable."
The Sprint All-Star Race weekend includes Friday's Sprint Showdown, a 50-lap qualifying race for teams not already in the main event. Segment winners (the race consists of two 20-lap segments and a final 10-lap dash) earn a berth in Saturday night's All-Star Race.
Now in its 32nd season, the All-Star Race itself consists of two 50-lap segments and a final 13-lap segment.
A Sprint Fan Vote winner will also make the Saturday night main event.
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