The Background and Buildup of the Danny Thompson Challenger 2.5 Bonneville Streamliner

With the historic running of Danny Thompson’s Challenger 2.5, we are posting this article by Thom Taylor that originally ran in the Sept. 2014 issue of HOT ROD. It gives some of the background behind the car and why it was and still is such a compelling pursuit.

The Challenger II streamliner was the brainchild of the hyper-prolific and ingenious Mickey Thompson. First constructed in 1968, it was noteworthy for its unprecedented who’s-who of talent. With drag-racing fabricator and driver Pat Foster overseeing the build, Thompson hired Quin Epperly (famous IndyCar builder and fabricator) for chassis construction, Tom Jobe (from “Surfers” Top Fuel fame), and Nye Frank (the proverbial Zelig of automobile racing endeavors) handling the many aluminum panels necessary to sheath the race car, with assistance from Lil’ John Buttera. Ford supplied money and engineering talent, with some fab help from Kar Kraft in Detroit. Though Thompson would pilot the machine, his backup driver was the talented Danny Ongais, just to complete the assemblage of the all-star aspect of this racecar development.

We should also add that this car was being constructed while Thompson was in the middle of building his Bonneville Mustang and three Mustang Funny Cars, one of which was the experimental “monocoque” car. Like we said, Thompson was nothing if not prolific.

The newly dubbed “Mickey Thompson Autolite Special” did well on initial Bonneville tests, but time, weather, and other pursuits mothballed the project until 1988. Pulling the wraps off of the then-20-year-old racecar, Mickey put together the first part of the funding to upgrade the Challenger II with son Danny planned to be at the wheel. Three weeks later, Mickey and his second wife Trudy were gunned down in their driveway.

Put back under wraps for another 20 years, Danny decided to take the wraps off of the old streamliner, access its ability to compete, and then begin the process of putting together both a car and team in the tradition of his late father. Danny and friends upgraded the car with still more tricks and improvements from its original 1968 incarnation to chase the dream of both he and his father to have the fastest time for a piston-driven land vehicle. Ever.

Then the rains came. As you now know, Speed Weeks 2014 and 2015 were washed out by a combination of too much rain and not enough salt depth to make a safe surface to race on. Over this period, Danny moved his family and shop to Colorado and then waited anxiously to see what the Race Gods had in store for 2016.

Danny sought many changes from Challenger II’s 1968 configuration. Gone are the two Ford SOHC engines originally powering the all-wheel-drive Streamliner, supplanted by two Brad Anderson 500ci A/Fuel-type engines. Richard Catton of RC Performance built the bottom ends with Bill Miller rods and pistons and Velasco cranks. Jerry Darien was responsible for the top end and figuring out the combo. The two engines are synced by an external driveshaft-like arrangement attached by Gilmer belts to the snout of each crank. The give of the belts will help to take up any deviation in engine speed, syncing the two in harmony. Initial tests will be with a blend of 50 percent nitro. That mix could change if additional power is needed, but Thompson wants to see how much of the power can be effectively put to the salt first.

The B&J three-speed transmissions are attached to synchronized air shifters for precise, instantaneous shifts. The huge magnesium quick-change axles are from the original build—a combined endeavor between Thompson and Ermie Immerso—as are the massive Kar Kraft radius rods. The only change will be with the steering arrangement.

The Challenger II was originally designed with stagecoach steering actuated by a 1968 Camaro steering box. The unusual solution was due to the limited amount of space available to keep the nose as small as possible. Danny Thompson has completely redesigned the front end to eliminate this unusual and outlawed feature, going with compact and complicated solidly mounted spindles—a study in fab porn. Positive offset wheels made by SK Specialties help keep this new arrangement neatly tucked inside the original nose, maintaining the small frontal area. The compact arrangement also meant creating stout, new shorty drive axles.

Out back the tail has been extended from the original design, and the body aft of the rear end was also lengthened and angled upward. A splitter will be attached to the underside to help stabilize the dirty air spilling off of the rear. Danny says the tail extension was more for cleaning up the air than stability, though that may be an added bonus—it’s hard to say at this stage. Tim Gibson was instrumental in determining the aero mods like the tail and air inlets, which were beautifully created within the original aluminum skins by Terry Hegman in Fountain Valley, California.

At 5,200 pounds, the rechristened Challenger 2.5 is plenty heavy, and Thompson is adamant that no additional ballast will be added. Many Bonneville racecars ply the salt loaded with weight to help keep them planted. Thompson has a problem with the idea of pushing and then stopping the extra mass. If there is need for additional downforce, he has aero pieces that can be added to the front and a tray for the rear. He feels that one of his advantages over the competition is the car’s four-wheel-drive system. “But that also means that we’ll need to make hay in the bottom end,” Thompson says. He also likes that the small frontal area will help his chances.

When the beginning car builder looks at a build such as this, the intimidation is 11 on a scale of 10. But all hot rodders can benefit from eyeballing this massive undertaking. One of the main takeaway points is that each system or function has to be designed one step at a time while keeping in mind how it will integrate into the car’s overall construction. In a build like this, packaging each system for minimum space and maximum function is important.
Taken in total, it is an unimaginable undertaking, but that’s not how to approach a build. Focus on each system separately—one at a time—and as you complete it, go on to the next system. Before you know it, you’ll have a partially completed car and be on your way to finishing what you have wrought.

Back in 2014, Tom Jobe stopped by Thompson’s Huntington Beach, California, shop and commented on the differences between how they built race cars in 1968 and how builders tackle projects like this today, lamenting that back in the day they used existing components and built a car around those pieces. Today, with the abundance of talented shops and equipment—not to mention huge budgets—they make all of the components to meet their own criteria.

Still, when you look at the car as it sits now—panels off and its complexity exposed—you’re struck by how contemporary it seems. The experienced minds and fabricators are evident in every square inch of Thompson’s Challenger 2.5. Today Danny’s challenge is to seamlessly blend the talents and dreams of a legendary father and his collaborators with his own determination to see those dreams realized 50 years later.