In the run-up to this year's 24 Hours of Le Mans, Danish racing ace Jan Magnussen had a frightening crash in the #63 Chevrolet Corvette. It was during the final qualifying session on June 11 as Magnussen was going through the Porsche Curves, a fast right-left-right-left section of the track. At 135 mph (217km/h), instead of turning into the first left-hander, his race car went head-first into the safety barriers lining the track, spinning him around and sending him backwards into a wall on the opposite side.

But shockingly, Magnussen escaped without injury. And given the spectacle, we had to find out how this was possible. We spoke with Corvette Racing's boss, Doug Fehan, at a recent round of the Tudor United Sports Car Championship (TUSC) in Watkins Glen, New York.

Magnussen's crash was traced to debris in the throttle-return linkage that caused the throttle to stick open. Although he was able to shed a little speed by shifting down a gear or two (and applying 1400psi/9.65 MPa pressure to the brake pedal), the team estimate his first impact was around 102mph (164km/h). As you can see from the video above, he lost very little speed before the second impact. The damage to the car was so bad that it couldn't be repaired in time for the race—so bad in fact that the car still isn't fixed and Corvette Racing had to borrow a year-old car that they sold to customer team Larbre Competition for the TUSC races that followed Le Mans.

Building a car capable of absorbing that kind of impact without harming the driver required some clever thinking by Pratt and Miller, the company that runs the Corvette Racing effort for GM. It's even more of a challenge because the C7.R race car starts life as a Corvette Z06 road car, made on the same Bowling Green, Kentucky, production line as every other Corvette. At its core is an aluminum frame, onto which needs to go a steel roll cage. And as you may well remember from chemistry class, sticking dissimilar metals together can turn them into electrodes, leading to galvanic corrosion

"We're in a unique situation, and it was a challenge," Fehan told us. "We use a chromoly steel riser, welded to a tapered plug with a threaded body. Next, we match that taper in the aluminum hydroformed rail and insert it to be bonded. But they're dissimilar metals, and we don't want galvanic corrosion. The solution was to use an adhesive to bond them together, but we want it as centered as possible to facilitate the bond. So we embed silicon beads into the adhesive, then torque it down into the pocket [in the aluminum rail] so it's one beads-width all around for a uniform thickness. That gives us uniformity of the adhesive and protection from corrosion."

According to Fehan, the team had tested welding the metals together as a possible approach before finding that wanting. "We took an aluminum sprue and slipped a steel rollbar over it, then seam-welded them together. We put it in a test facility and applied pressure to try and break it, and the weld would not break. It was actually the chromoly steel that snapped [before the weld]," he said. "We thought we had it made, but Gary Pratt [Pratt and Miller's VP] wasn't convinced and said we need to do some impact testing. If you hit that weld with a ballpeen hammer, it fractured. Zero tolerance to shock, even though the bend-and-fold strength was great."

From there, the rest of the steel roll cage is welded to the steel plugs in the chassis. Although the cage has proven itself more than once (Magnussen also had a mighty crash last year at Virginia International Raceway), next year's C7.R race cars will have a new version, spurred in part by the need to have a safety hatch in the roof so emergency workers can insert a backboard to immobilize the driver's spine in their seat if necessary. Fehan told us that the new cage is lighter than the current car's, but it happens to be even stronger.

Other driver safety improvements are coming to the seat as well. Corvette Racing uses a hollow clamshell for the car's seat because it doubles as the mandatory driver cooling system, blowing cold air through it (just like the optional cooling seats you can get in the road car). The team is working on adding head restraints to the C7.R's seat, although this is a challenge compared to a series like NASCAR because of the need to perform quick driver changes during pit stops in endurance racing.

We asked Fehan about some of the other safety features on the C7.R. One of the most significant ones is a side impact box that sits between the roll cage and the door. "We worked with Wayne State University to pick the right aluminum honeycomb material, then encased it in kevlar/carbon [carbon fiber with kevlar strands in the weave]. It's actually bullet proof—we've fired weapons at it! We thought it might be overkill when we initiated the program but two years ago Johnny O'Connell had a bad crash in the Cadillac race car [also built and run by Pratt and Miller], and a suspension arm from the other car penetrated the door of the car. The box stopped it from impaling him."

Finally, we asked Fehan where he thought some of the most promising future developments in safety were likely to come from. "Materials," he said, pointing to the danger from head impact injuries in racing but also football. "In my lifetime in this business, 200 mph (321km/h) seems to be a threshold. If you stay 200 or below, survivability is pretty good. Above that, the human body is at huge risk; materials fail, energy isn't absorbed at the rate it should be. I don't see the point in going more than 200. You can't tell 200 from 230 at Indianapolis without a stopwatch. When human lives are at stake, I'm not anxious to be a part of that. We're running at 190 mph. In these cars, for all intents and purposes, that's safe."

Le Mans was a bust for Magnussen and his co-drivers, but the team's sister car was the class of the field, winning the GTE-Pro class. It was Corvette's eighth class win since 2000. Although neither Corvette won a trophy at Watkins Glen, Magnussen and his teammate Antonio Garcia did finish third in last weekend's TUSC race at Canadian Tire Motorsport Park in Canada (using the borrowed car), putting them back into the lead of the highly competitive championship. Safety and success go nicely in hand.

Listing image by Jonathan M. Gitlin