The sweltering heat and hordes of insects are the first things that greet you when you get out of the car at the gate to Buttonwillow. Checking into a modest clubhouse, you sign your life away, pay the entry fee, and get a wristband in return. Somehow it doesn’t seem like a reasonable trade.

My spirits lifted when I found Valkyrie’s pit and saw their gleaming white cars underneath—thank you Jesus—a canopy. Getting to write about these cars from a distance is enjoyable, but seeing them in-person is a treat. The details take hours to fully soak in. To think their race cars were built from road-going Nissans makes you wonder how many hours, how many busted knuckles, and how many holes punched in a wall were needed to get them to this standard.

Valkyrie Autosport, a small team based out of Santa Cruz, California, race their Nissan Z cars in various NASA Pro categories. Their lead driver and team owner, Brian Lock, once raced in Grand-Am and Redline Time Attack, but has since divided his time between running his shop and keeping his backside in the racing seat. Driving alongside him for this three-hour enduro was his business partner, Giles Powell. Among the mechanics and drivers at Valkyrie Autosport, their chief ambition is to win the grueling 25 Hours of Thunderhill—a feat they managed last year in their stunning 350Z racer. Once I arrived at the Valkyrie tent, all I could do was sit, slack-jawed, before their incredible racing cars, soak in the details, and wait for the race to start.

My timing wasn’t too bad. Shortly after I arrived there, their 370Z fired up, and as Lock clicked the Quaife ‘box into gear and rolled away, and I started eyeing the competition. Lock had a good 360 horsepower on his side, plus sticky Hoosier slicks, JRZ suspension, an Aeromotions wing, and SPL suspension links, but he was up against some serious machinery.

The NASA E0 sprint race was filled with a variety of cars, including Corvettes, stock cars, vintage 911s, a top-dollar Ginetta prototype, a Lamborghini Huracan, and a GT3 Cup Car, just to name a few. The varied field also featured a few Spec Mustangs, which acted as moving chicanes for a frustrated Lock, who fought tooth and nail to stay ahead of a Lancer Evolution throughout the entire race.

Sprinting Towards the Sunset

Though the sprint races aren’t what mean the most to Lock and his team, they are good indicators of their race pace, and serve to help develop the components that make a once-plush cruiser competitive with a range of race-bred cars which ought to be in another league. What’s more, sprints give them the chance to run in heavy traffic, plan moves well ahead, and deal with the specific challenges that this specific track provides. At the dusty, extremely-flat Buttonwillow, the team was barraged with plenty of annoying little hurdles.

Throughout the sprint, their main competition was a well-tuned Lancer Evolution VIII. While the Valkyrie 370Z was comparable down Buttonwillow’s straights, that would have to be chalked up to the Quaife sequential gearbox, since the turbocharged Evo had slightly better thrust at the lower end of the rev range. Where the 370Z undoubtedly had an advantage was through the high-speed and medium-speed corners, thanks to the downforce and stability offered by the Aeromotions rear wing.

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Where the Evo was unquestionably stronger was in the slowest corners. Four-wheel drive and strong low-end torque allowed the Mitsubishi to close the gap in technical sections; specifically the Turn Two hairpin. It was really a matter of traffic or a mistake that would decide the rightful owner of second place. After the pole-sitting Corvette spun, Lock had to defend second with the Evo and a Camaro nipping at his heels.

As both novices and professionals came to terms with the challenging circuit, the inevitable dropped wheels would bring dirt and debris back on track, and though the Evo might be at home sliding over loose surfaces, it didn’t do Valkyrie’s 370Z any favors. While their FFTec–tuned Motec M1 traction control system could prevent the rear wheels from spinning furiously over the strewn earth, it couldn’t generate traction. And it certainly helped—the Z managed to keep a decent cushion through the tight, off-camber corners that might traditionally upset a front-engined, rear-wheel drive car with a good amount of torque.

However, after a long nose-to-tail battle with a few indefinite changes of position, the Evo’s driver snuck by in a dusty hairpin, and, with the help of traffic, started stretching a lead. Lock kept charging and caught the Evo on the last lap. Struggling to hold his position, the Evo went wide in Turn 2 and made contact with an out-of-class competitor and spun! Persistence paid off, and with the gods smiling on him that day, Lock secured a second-place finish in a grueling sprint.

Dicing in the Darkness

As the fifteen-minute warning for the three-hour enduro rang out in the pits, the once-jovial atmosphere in the Valkyrie tent became vaguely tense. Lock’s car for the enduro would not be the speedy 370Z, but his resilient and proven 350Z. As he quietly strapped into the older Z car, I kept my distance—I know better than to interrupt a determined man trying to focus.

Whatever he told himself in those uncomfortable minutes before the start seemed to work, since Lock had a searing start and kept up at the sharp end of the pack. Though the 350Z was not the quickest car down the front straight—and I don’t mean that euphemistically—what struck me was its stability in the braking zones and its speed through the long, tightening left that is Turn One. Barring the incredibly quick Ginetta protoype, nothing could gain much distance on Lock through this particular section.

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The sun was setting on the horizon, and with no city lighting, things got very dark. After the first ten laps, the drivers accepted their general position and settled into a rhythm.

By that point, Lock was primarily concerned with two things: visibility and ensuring the car lasted. After the sun sets at Buttonwillow, it’s hard to get an indication of where to go. The track is exceptionally flat; there aren’t many landmarks to use as reference points, and with no hills to bounce highbeams off of, it’s tough to get a sense of where one’s going.

This is compounded by the odd dust cloud spat up after an off-track excursion, and at night, that dust seems to linger for a couple laps before being completely blown away.

Whenever barreling through a brown cloud, Lock relied on muscle memory; tracing the right line despite not having visual recognition of the track for a good three seconds and lifting slightly to minimize the chance of running into something on the other side of said cloud. It’s amazing that commercial pilots manage this sort of thing, and they’re not trying to outbrake other 747s.

What really plagued Lock throughout this fumble in the dark was the differential. With the debris on circuit, the differential was working overtime to keep the rears hooked over the dusty surface. Noticing his differential fluid temperature rising into the red, Lock adapted to the situation.

Instead of a forceful application of throttle while still holding some steering lock, he reverted to a textbook style of driving. When rounding out of an apex, he would wait until the steering was nearly straight before giving the motor the full beans. Though this helped the differential temperature stabilize, it faced him with another issue.

Now roughly three seconds a lap slower with the bloodthirsty BMW E36s steadily closing the gap, Lock had to compensate for his gentler corner-exit approach. Since the motor had proven its robustness in the past, he felt it safe to spin it to 7,500 rpm to try and negate his losses elsewhere.

Ninety minutes in and maintaining a cushion of ten-to-twenty seconds over second place, Lock pitted from first place and handed the car to co-driver Giles, who carried the flag for another hour before pandemonium struck. Well into his stint, Giles took a facefull of dust after a BMW careened off the track just ahead of him. Now unable to see properly, he felt it was wise to put their $100,000 racing car in the hands of someone with functioning eyesight.

The problem with a premature pit stop wasn’t the timing, as much as it was the lack of working radios. As the white 350Z cruised into the pits unannounced, the team scrambled wildly to get Lock, who was just forcing down a burger patty, back into his racing suit and into the car. Amidst a flurry of profanity, they wrenched Giles from the seat, shoved Lock back into the rolling sauna, and topped off the fuel before he roasted the Hoosiers on the way out of the pits.

Fortunately, for Lock, Giles last few laps had been at a slower speed, and the car cooled as a result. With the bit between his teeth and a burger digesting in his stomach, Lock summoned all his skill and threw the accepted rules of enduro racing out the window. Less than a half-hour to go and Lock committed himself to driving the tires off the thing. Differential temperatures be damned!

He no longer needed to conserve tires and it showed. Standing at the edge of Turn One, you could observe the Z’s back end dancing around. Through faster corners like Riverside, Lock kept the throttle pinned, and even from a distance, it was easy to see the crimson wiggle of the taillights as the Z’s backside wobbled at eighty miles an hour.

Lock gave no quarter on the brakes and slipped by some traffic by, well, slim margins. As I stood by observing and gnawing my fingernails, he took his courage in his hands and really chanced it a few times when shoving his way past backmarkers. Though not full-out kamikaze, the last few minutes could’ve ended quite badly if not for what can only be described as luck. I’m sure it seemed measured inside the cockpit, but from the outside it was pretty nerve-racking stuff.

Lock’s charge kept him from losing third place, despite being at a massive fuel disadvantage. While the rules state that all competitors must run only as much fuel as the OEM tanks could carry, it’s hard to police. Knowing full well the consumption of their rivals, Valkyrie’s attention was piqued when they noticed an E36 making a one-stop strategy when everyone else was forced to make two.

After some quick computation, they sensed foul play; their rivals had installed a larger fuel tank than the rules allow. As Lock states, “the rules need to mandate two stops; that way, they’ll keep the costs down and the playing field level.” A post-race review by the stewards excused the BMW’s “misinterpretation” of a poorly written rule, and results would stand. Pity.

After a much-needed modification of the rules, every car in the next NASA WERC event must one-stop the race to be competitive. This proposes a new challenge: the Valkyrie team will have to run at a similar pace while consuming four fewer gallons over the course of three hours. That’s no simple challenge.

Being the perfectionists they are, Valkryie found their third-place finish somewhat disappointing, but they’ll use the experience to help prepare for this year’s 25 Hours of Thunderhill, which is and has always been their main target. Their plan for the moment is uncertain. Maybe they’ll run their 370Z with a new Jim Wolf crank, bigger cams, 13.7:1 compression, flowbench-tested heads, and an estimated 400 horsepower! Even with a neutered engine map required to run in the E0 class, it should be more than enough to nip past those pesky BMWs.