Valkyrie’s 350Z Wins at the 25 Hours of Thunderhill


Photo credit: Hilary Frank Photography

Valkyrie Autosport had been working night in and night out to get their 350Z up to race-shape, and inevitably, something had to break. Like with all long-distance races, these little niggling issues would dog their attempts, but they began well before their attempt at the illustrious 25 Hours of Thunderhill.

Last August, their race at Miller Motorsport didn’t go well; a brake line issue would keep them from reaching the podium. While their 350Z was leading with five laps in their pocket, a failed crossover pipe caused by bad vibration from an ailing wheel bearing forced them into the pits. Though only stopped for fifteen minutes, they returned to stage an amazing comeback until another crossover pipe failure pushed them back to fourth by the time they crossed the finish line. “We were disappointed since we were so close – we really wanted to get monkey off our back,” recounts team owner Brian Lock. After snagging that first victory, winning becomes easier – at least in one’s mind.

Twenty-Five Grueling Hours

However, their luck turned around several months later at the heralded 25 Hours of Thunderhill. Before the machinery could endure the abuse the event throws at it, a few upgrades were in order. With a new longblock from Nissan and Jim Wolf Technology’s most aggressive cams, the motor made 324 horsepower at the rear wheels, and gave them the reliability necessary to finish the race.

Nearly the entire SPL Parts catalog was implemented to last the twenty-five hours.

Nearly the entire SPL Parts catalog was used to last the twenty-five hours.

This stout powerplant would help navigating the slower categories – one of the main hurdles faced in endurance racing. With plenty of torque and a good amount of tire, slower traffic can be easily passed on the straighter portions of the track. In the long run, this is an invaluable ability to have, since it limits the amount one has to squeeze by, take risks, and generally abuse their tires to pass.

With sixty cars making up the field on the classic Thunderhill, managing traffic would always be a challenge. They managed to avoid a bit of the slower machinery from the start with a stellar qualifying lap of 1:53.7, which placed them sixteenth overall. All was running smoothly until a seal in the power steering blew twelve hours in. At that point, they had been six laps up, fending off a Nissan 370Z. The Valkyrie 350Z had the 370Z covered on outright pace, but not while nursing a failing power steering rack.

Keeping the car alive without wasting time in the pits is endurance racing's great balancing act.

Keeping the car alive without wasting time in the pits is endurance racing’s great balancing act. Photo credit: Hilary Frank Photography

However, with their 350Z running a massive 275-section front tire and puking power steering fluid, the front end was difficult to manage, and the two Zs were fighting tooth-and-nail. With the class victory in sight, they had to keep their focus and morale strong, despite having to refill the reservoir every thirty minutes. The most troubling concern was that a seized power steering pump could break the belt, which was attached to the alternator, and in turn, could have knocked out the dry sump. 

Mechanical attrition can also be a friend. Like the Valkyrie team was afflicted with their power steering issues, the competing 370Z broke an axle with two hours to go! Additionally, the Bimmerworld E46 M3 running in third was kept at bay with brake issues. It seems that Valkyrie’s preparation paid off that day, but only by a slight margin. It’s been thirteen years in the making, but Brian Lock and his dedicated team finally tasted the sweet nectar of victory after winning the E0 class, though it so nearly ended well before they crossed the finish line.

Smiles all around for the Valkyrie Autosport team.

Smiles all around for the Valkyrie Autosport team. Photo credit: Hilary Frank Photography

Panic in the Night

That victory nearly evaded the team. As they ran into the night, a close call with a stalled prototype could have ended it all. With the clock just ticking past ten o’clock, the flood lights lining with pits were blazing; limiting visibility when running down the front straight which ran parallel. At night, it’s tough enough finding the turn-in point, but when one of the leading prototypes stalls while blending onto the track, which happens to be the same spot as the ideal turn-in point, things can get exciting very quickly.

Photo credit: Hilary Frank Photography

Photo credit: Hilary Frank Photography

It didn’t help that the Wolf prototype was painted flat black, and the minute size only worsened things; it only became visible when it was within spitting distance. Nearing 130 mph towards the end of the straight, Lock just noticed the stalled car as his 350Z, a Civic, and a Miata were all running three-abreast. The Civic, closest to the blend-line, collided with the prototype, and spat debris everywhere. Lock took evading action and just managed to miss both the flying debris and the Miata swerving wildly to avoid the chaos. Thankfully the cost was only a few gray hairs.

Even with more than a day to race, a few close calls are inevitable.

Even with more than a day to race, a few close calls are inevitable. Photo credit: Hilary Frank Photography


The night brings other challenges. Since it’s hard to make sense of the surroundings with the faster traffic’s headlights filling the mirrors, depth perception becomes a major issue. Therefore, braking points become based on rpm instead of the typical visual markers. Lock notes, “I would think ‘I reach the top of third gear before braking here’,” instead of looking for the hundred-yard board beside the track. Somehow, the times remained consistent.


Brake markers and other reference points go out the window at night. Photo credit: Hilary Frank Photography


Interestingly, lap times were not any different at night. Their target lap time was 1:58, roughly five seconds off their qualifying time. While the car was robust, it took a slightly gentler driving approach to ensure consistent performance over the entire day. Since they ran 677 laps in the race, they would typically run a gear higher in most corners to save the transmission, the tires, and the fuel. Whereas in qualifying they were “steering with the throttle and countersteering everywhere, in the race, I was rolling through those corners,” explains Lock. Nevertheless, they still went through six sets of Hoosier slicks.

Plans for the Future

Next year, they intend to run their 370Z in the ES class, but with some serious modification. We’ve covered this car before, but to be competitive with the big boys, they’re considering some very interesting upgrades. A Quaife sequential gearbox has been purchased and installed. Fitting it in was a cinch since it required no fabbing aside from a special crossmember brace and a custom driveshaft.

Since we last checked on the car, it’s been torn down, with bits added to reinforce and stiffen the chassis. Lock is in the process of adding air jacks, and a Motec ECU with data logging and the whole nine yards is next. The powerplant might be in need of an upgrade, too.

With GT-R power, this car could be a serious threat.

With GT-R power, this car could be a serious threat.

Since the VQ37 has to be revved to the moon to make a competitive amount of power, it’s not very reliable in long-distance events. For that reason, the Nissan GT-R’s VR38 has been considered. It would weigh the front down slightly with turbos and an intercooler, but surprisingly, heat would be less of an issue. Not having to rev nearly as high and having that low-end torque offered by a turbo engine could make a world of difference, and make it one of the most impressive Zs raced in North America. We wait with bated breath.

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About the author

Tommy Parry

Tommy Parry has been racing and writing about racing cars for the past seven years. As an automotive enthusiast from a young age, he worked jobs revolving around cars throughout high school, and tried his hand on the race track on his 20th birthday. After winning his first outdoor kart race, Tommy began working as an apprentice mechanic to amateur racers in the Bay Area to sharpen his mechanical understanding. He has worked as a track day instructor and automotive writer since 2012, and continues to race karts, formula cars, sedans, and rally cars in the San Francisco region.
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