Lavon Miller, the owner of Plain City, Ohio’s Firepunk Diesel, has been building and testing engines for years now, but he never had one blow up on him like this six-cylinder diesel did on Thursday, which he got up to 2,200 horsepower before things went south. He’s still investigating exactly what went wrong.

The triple-turbo, 6.7-liter Cummins is about three years old, and has gotten around 140 psi of boost, Miller told Jalopnik, and has, “seen a good bit of abuse.” But that doesn’t quite explain the explosion, Miller said.

“There was something that happened inside the engine right before it came apart,” Miller said, adding that he and his team at Firepunk are looking at the video frame-by-frame. One early suspect? A firing failure that could have ignited a companion cylinder. Miller says they’ve cracked a block before in engine testing, but, “We shouldn’t have had a block failure.”

Miller has successfully gotten the same engine up to 2,200 horsepower before, and was hoping to get this one up to 2,400 horsepower, after making some tweaks to the turbos.

Advertisement

“It was still on its way up,” Miller says.

Miller’s no stranger to insanely powerful diesels, and Firepunk has raced in—and won—numerous competitions in the past few years using engines the company has built. A couple weeks ago, Miller posted video of a different engine (successfully) putting out 3,000 horsepower at 5,500 RPM. And if 140 psi sounds unbelievably high, other diesels have run even more boost.

All that’s left of the destroyed engine is the head and the injectors, Miller says, with the rest likely to be trashed. Now Miller’s also left with some forensic work to do, which started not long after the explosion. First though, they cleaned up for a couple hours.

Advertisement

“It’s a lot of wreckage,” he said. “I’m just glad this didn’t happen at the racetrack.”

[h/t Paulo]