Q&A: Answering questions about the NASCAR Xfinity Series composite body – Autoweek


In the name of cost containment and improved competition, NASCAR is set to debut a new flange-fit composite body next weekend for the Xfinity Series race at Richmond Raceway.

This is the first of a three-event optional rollout this season that will also include the races at Dover International Raceway and Phoenix Raceway. The new body will be optional for every race except those at Daytona International Speedway and Talladega Superspeedway next season before becoming mandatory in 2019.

The project goes back to 2015 when a composite body was first introduced to the ARCA Racing Series and NASCAR K&N Pro Series. This is an evolution of that body with NASCAR, Xfinity teams and Five Star Bodies working in tandem to produce something that works for the entire industry.

So here’s everything you need to know about the new Xfinity Series composite body:

Put it bluntly: Why is NASCAR doing this?

NASCAR and Xfinity Series teams are trying to limit costs and increase parity. I explain how below.

Is this just for the NASCAR Xfinity Series?

For now, yes.

Brett Bodine, senior director of NASCAR R&D says conversations have started with Cup and Truck Series teams, but the industry is going to monitor the Xfinity Series rollout before making such a decision at the highest level.

Current bodies are steel sheet metal but the new composites are made from fibrous materials including fiberglass, kevlar, and carbon fiber. The exactly blend is a Five Star Bodies trade secret.

When will the new bodies be used?

NASCAR allowed Xfinity Series teams to decide how the new bodies would be rolled out. They opted for Richmond, Dover and Phoenix this season. They also decided to approve them for every race EXCEPT Daytona and Talladega. The composite bodies will be MANDATORY in 2019.

“The rollout schedule was a collaboration by all three parties — the teams, OEMs and the sanctioning body,” Bodine told Autoweek on Thursday. “The teams decided the timeline… We gave them a lot of options and they chose Richmond, Phoenix and Dover this year; and they chose everywhere but the susperspeedways next year.

“Part of the garage wanted to keep the steel cars available next year. We’re going to have to keep doing things to make sure there is competition parity to where the flange fit body because it weighs 160 pounds less than a steel car.

“So the steel car has to remove the aero pan in the front so aerodynamically it will be at a disadvantage. Everyone wanted to make sure this was the body of choice but we wanted to make sure teams could still use their backup cars if something happened.”




nascar flange fit xfinity bolt on photo




How much money will it save teams?

That’s difficult to say. The cost of a composite body isn’t drastically different that a steel body, but the cost containment is found in installation and labor.

The composite body has 13 flange fit panels and each of them bolt together instead of needing to be welded to the chassis. Bodine says that is where teams will save on time and labor.

“The biggest area we’ll see in effectiveness is in the turnaround time from race to race,” Bodine said. “You scrape the side of a steel body car and you have to cut the side off. Then you install a new one, hand-form the metal, weld it on and make sure it fits. Then you send it to the body shop and bondo it up, make sure it fits on the grid again.

“This car here, you tear a side off it, unbolt it, bolt on a new panel and make sure it fits. That’s it.”

How will this make the racing better?

The benefit of a composite body car is that it’s considerably more difficult to aerodynamically tamper with than its steel counterpart. It’s no secret that teams massage the body to find aerodynamic advantages in the wind tunnel before even hitting the track.

With composite cars, teams have to run the bodies as purchased from Five Star Bodies in Twin Lakes, Wisconsin — the manufacturer of the K&N and ARCA composite bodies.

The new Xfinity body features a raised honey comb pattern on key parts of the cars where teams are prone to alter the body to find aerodynamic advantages. Effectively, the new body makes the cars more ‘spec.’

If teams try to massage the composite body, it becomes obvious that tampering took place because the honey comb pattern will appear altered to the naked eye. The pattern even appears after being painted or wrapped.

In fact, the pattern must be visible for the car to pass inspection. And it also renders bondo and sanding completely obsolete.

“The most obvious advantage is that the body is not manufactured by the teams,” Bodine said. “It has to be raced as sold by our supplier. We’ve instituted the security pattern, the honey comb look, in critical aerodynamic areas: A-post, B-post, C-post and quarter panels … these are all areas that teams like to mess with.

“These markings have to be visible at all times. We’ve wrapped it to show you that they are still visible after wrapping or painting. With this car, you can not apply any bondo at all so the door seams, they have to be there and you can’t bondo them in. The other part of the security is that the panels interlock, there’s an interlocking feature. You can’t misalign the panels.”




nascar flange fit xfinity security measure photo




How will this affect the five-minute crash clock?

It won’t. Teams are not allowed to replace any of the 13 panels DURING THE RACE. However, panels can be replaced during practice or qualifying. In fact, crash damage that typically requires a back-up car may be easier to repair at the track since the composite panels are easier to bolt on than the fabrication that steel cars require.

What will be different during the inspection process?

Beyond the security markers, nothing should change.

The current templates will continue to be used in the inspection process. There are also markings on the outside of the car where a laser system will be used, starting at Richmond, to ensure the body is square to the frame.














By Matt Weaver