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Tucked away up in a Spring Valley garage up a gravel driveway, hidden behind piles of junk cars varying in age and integrality, it looked more like a mechanic’s yard sale than what might just be the fastest vehicle on wheels in the Roaring Fork Valley.
Tires, engine parts and nuts and bolts scattered about it, Tim Boyle — sporting a blue baseball cap conspicuously devoid of the layer of dust, grease and oil that had built over time on much of the other items in the space — bent over a chassis that appeared more akin to a piece of a metal cell phone tower than a vehicle; long and narrow, with welded cross sections for support. Even in one piece, “Thunder in the Morning” looks more like a 30-foot-long rocket ship than a car.
But in early August on the Bonneville Salt Flats in Utah, the chaos came together to make Boyle’s Salty Box Racing Team a world record holder — and if all goes to plan, it’ll cement them in the record books even more.
“If we end up being the fastest diesel in the world, that will be the cherry on the cake for this year,” Boyle said.
On Aug. 8, the diesel streamliner hit an average of 315 mph across two runs at Bonneville Speed Week, breaking a nearly two-decade old world record for the C-class of diesel streamliners, a diesel-powered vehicle built to minimize wind resistance. Its class size is determined by engine size: Boyle’s vehicle has a 5.9-liter Cummins common rail engine with a compound turbo setup.
Tim Boyle sits in Salty Box Racing's diesel streamliner as its parts lay spread on the body in his shop in Spring Valley on Wednesday. The streamliner became the fastest in its class at the Bonneville Salt Flats during Speed Week in early August, and Boyle hopes it'll become the fastest diesel in the world in a couple of weeks.
Rich Allen/Aspen Daily News
It broke a class record that was set by Roy Lewis — founder of Illinois-based Chassis Engineering — in 2006. And it was the fastest one there this year all around — beating another vehicle in the bigger-engine A class by 42 mph.
Per GPS tracking, the car got up to 324 mph at its peak. Its official top time in its first run was 312 mph. They held nothing back in the second run, reaching 318 over a one-mile interval.
Boyle credited Ryan Milliken of Hardway Performance in Mary Esther, Florida, with the tuning of the engine and the electrics. On Instagram, he listed off 15 crew members and 16 companies and shops for support of the team in its search for records.
It’s been a long time coming for Boyle, who has been running in the salt flats since 2005, but bought this car from old time racer and friend “Fast Fred” Dannenfelzer in 2019. Dannenfelzer built the vehicle, but didn’t race it because he couldn’t safely get out of the fighter-jet-like cockpit under his own power at his age. When Boyle was looking to build his own streamliner, Dannenfelzer told him it wasn’t for sale, but sold it to Boyle because he knew he’d work on it and race it.
Dannenfelzer passed away on Sept. 11, 2023, according to the Santa Barbara Independent. A decal that reads “Fast Fred; 1937-2023” sits on the streamliner’s body behind the driver’s seat, immediately to the right of a sticker commemorating the record.
Getting the vehicle — adding it to Boyle’s fleet of souped-up vehicles, a 1931 Model A and a Dodge Ram 2500 — was just the first step. The Salty Box team couldn’t quite get it ready in time for its inaugural season in 2020. Then in 2021, it reached 321 mph on its qualifying run, but exploded its intercooler and couldn’t back up the record. The last two years, the event was rained out.
This year, everything came together — though not perfectly. A crosswind threatened to push the streamliner off course, and “gremlins” in the motor and electrics loomed.
“It wasn’t like an ‘off the trailer and done.’ It was a few days of perseverance between sticky salt jamming in around the back tires and then electronic gremlins on the motor,” Boyle said. “It hasn’t been like an instant gratification; it’s been an uphill battle.”
Part of the reason for this week’s deconstruction was damage to pistons, which got hot and grabbed, putting the entire engine block in jeopardy. But “Thunder” made it through Speed Week and gave Salty Box a new record.
And the timing may not have been better: The Model A first ran for Boyle and Salty Box in 2005. The team is celebrating its 20th anniversary of making trips to Bonneville this year.
Because of the occasion, they got all three vehicles working and transported. In total, the team took 17 runs with seven different drivers across the fleet.
Boyle was behind the wheel for the record. Bonneville recognizes drivers for reaching high speeds — but you only join a club if you break a record along with it. He said there’s about 800 people in the 200 mph club — “Still less people than have been to the top of Mount Everest,” Boyle said — for which they award you a red hat with the appropriate insignia. He already had a red hat.
For the 300 mph club, they give you a blue cap, still with the 200 mph club logo, but with “300 M.P.H CHAPTER” sewn into the side. Only 150 to 200 people have a blue cap, Boyle said.
On Wednesday morning, Boyle and Salty Box Racing team member and de facto photographer Robert Murphy packed up engine parts and other pieces of the vehicle, preparing to load it and the others up for a trip to Denver for some maintenance, as the work isn’t done for the season.
“It’s the pinnacle of motorsport,” Murphy said. “When you go separate racing, rally racing, motocross, you’re racing against a person. When you do this, you’re racing time. Time doesn’t change and you’re trying to beat, in your class, everyone that has ever come before you.”
Salty Box will be back in Bonneville in a couple of weeks for the World Finals, chasing more hats and another record: the overall diesel streamliner record at 328 mph, set by a team called JCB DieselMax in 2007, backed by the JCB Excavators, a construction/agriculture equipment manufacturer.
“That’s ultimately what we’re after,” Boyle said. “I think we’ve got it, we’ve just got to put the engine back together nicely and make sure we don’t make any mistakes when we’re actually racing, and ultimately be able to say we’re the fastest diesel on the planet.”
But this time, it likely won’t be Boyle behind the wheel. It’ll likely be Milliken or another member of Salty Box, Adam Rogers, he said.
Why? Because Boyle wants more people to get a hat.
“I’ve got my blue hat now, I don’t want to be greedy with the driving duties,” Boyle said. “It’s a team effort. It’s not me, it’s we.”