Before the Valkyrie Autosport Nissan GT-R could take on the 25 Hours of Thunderhill in 2018 and 2019, the team had to convert it from a street car to a racecar, which began with stripping it down and installing a cage.

The Valkyrie Autosport Nissan GT-R is the only one of its kind in all of NASA racing, but believe it or not, it’s not the first one Valkyrie Autosport’s Brian Lock has built. This is the second GT-R he has prepped for competition. The first one was a factory-fresh car he built for time attack competition back in 2010.

“The first car was purchased by a client of mine in a partnership deal brand new with like four miles on it, and we drove out to Idaho, at the dealership that it was purchased at,” Lock said. “We picked it up in the showroom, took a few pictures and drove it back to their service center and completely gutted it, right there in the dealership. The dealership mechanics and salesman were standing around with their jaws on the floor, just couldn’t even believe what we were doing to this brand new GT-R.”

Lock initially envisioned building the first GT-R to race in the 25 Hours of Thunderhill, but the program and its partners took the car in a different direction and it wound up being a time attack car. That car was wrecked at Pikes Peak and ended up sitting. Lock looked into buying it back, but when he drove from his home in Santa Cruz, Calif., to Salt Lake City, the car was in much worse shape than he was led to believe, and he drove home empty-handed.

It was a disappointment for Lock, because he and his wife built that first car together before they were married, so there was some sentimental value in it for both of them, but it was too far gone for them to bother with. So they started looking for another one.

The one they found had about 50,000 miles on it. They transformed that donor into the car they campaigned to finish fifth in E0 at the 25 Hours in 2018 and to win ES with at the 2019 25 Hours of Thunderhill. This is the first in a four-part series on how this car came together.

Obviously, the first part of a racecar build starts with stripping it down and installing a roll cage. Since Lock had already built one GT-R for competition, he had experience with the chassis.

Valkryie Autosport tied the cage to the main dash bar and gusseted to the A pillars.

“I made sure that for example, where the main hoop landed and the rear half of the cage would facilitate a large fuel cell at some point,” Lock said. “I made sure that the mounting points for the front of the A pillars were where I wanted them to fabricate air jacks again down the road. Things like that were the main design points going into the cage. There’s a reason why the car is heavy as it is. The thing is just a tank and the OE pieces are incredibly rigid and really are in my estimation, the best weight bang for your buck, as far as chassis rigidity goes. So you don’t need to do too much in a cage.”

The door bars are pyramid X design, with gussets and IMSA bars that support the front hoop.

Some critical elements of the cage include the pyramid X design of the door bars and tying the main hoop of the cage to the B pillars and attaching the front hoop to the A pillar. Lock also integrated the factory dash bar into the eight-point cage. Lock did all the fabrication work at Valkyrie Autosport.

“I’ve always been very underfunded my whole career and it just by necessity had build my own cars and teach myself to build my own cars. So I’ve had plenty of opportunities to work on that side of it, that craft,” Lock said. “My brother and I started building cages together, I guess about 15 years ago and just a lot of tearing through as many pictures of the factory built race cars and looking at what the tendencies were and using my brief mechanical engineering experience while I was in college before I left to go pro racing to try to understand why they were doing what and did my best to copy it.”

The main hoop ties into the B pillars and an X brace connected to the rear wheel arches just forward of the upper shock mounts.

Though the GT-R is a fairly large car and easy to fabricate in, one of the biggest challenges to building it was to allow for modifications the team would be doing in the future, such as a larger fuel cell in the stock location. Lock also elected to leave the stock stiffener in place between the trunk and passenger compartments. Held in place with some 35 fasteners, the cast aluminum panel stiffens the chassis without the additional heft of steel.

Valkyrie left the factory aluminum rear stiffener in place. Attached with 35 fasteners, the stiffener spans the entire car between the trunk and passenger compartment.

“Anytime you do a steel tube, even on a 4-inch mounting plate, you’re still going to have deflection around that mounting plate. That factory piece is bolted in so many locations,” Lock said. “There’s just no way that I could be sure that I would remove that and not be hurting the rigidity of the car without putting in heavier steel and its place. That’s a very, very cool engineered piece, if that makes sense.”

Valkyrie Autosport’s Brian Lock has been fabricating cages for 15 years. IT shows in the quality of the work

Lock fabricated gussets for critical locations throughout the cage. For example, the X bar on the main hoop is gusseted as are the door bars and the braces at the top corners of the windshield. There’s ample triangulation and a vertical brace on the front hoop that ties into the mounting plate at the floor/rocker junction. He even included a beefy bumper bar up front.

It’s a solid foundation for a car that already has one class win at the 25 Hours of Thunderhill to its credit. The car is still being developed and there are lots more detailed stories to come on its suspension and setup, its electronics and preparations for reliability.

Valkyrie Autosport used big, beefy gussets to attach the main hoop and door bar to the B pillars.

“I hope people enjoy the story,” Lock said. “The first season we had the rebuild of the car this year and turning it into the absolute ridiculous monster that it is now … it was a hell of a thing.”

Valkyrie Autosport fabricated a tubular bumper bar to protect all the delicate pieces in the front end from damage.
Image courtesy of Brian Lock

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