1930 Custom Hupmobile
Bonneville Salt Flats Racer
Built by “Dock Knoch,” the Colorado doctor and hot rodder who saved Ab Jenkin’s life.
To Be Sold At Auction
History of the Hupmobile Bonneville Roadster
The “Bonneville Hupp” was originally owned and built by Dr. Norbert Knoch, a physician from Denver, Colorado, who typifies the racing enthusiasm that took hold in America during the 1930s, despite the hardships of the Great Depression.
Knoch’s pursuit of speed was so relentless that he ended up working with executives and engineers at not only Hupmobile but also Ethyl Gasoline Company, Gambill Motor Company, Kendall Refining, Schwitzer Cummins, Ray Day Piston, and Firestone Tire.
Knoch also recruited future racing legends like Bill Kenz to his team, traded racing parts with Babe Stapp, and acted as race physician to David Abbott “Ab” Jenkins on his record-setting runs in 1937.
Dr. Knoch bought his Hupmobile Model H right off the showroom floor at the Hupmobile dealership in Denver, Colorado. We’ve even been able to obtain the original title.
Originally a four-door touring car, the Hupp was brought to the Niederhut Carriage Company, a carriage company local to Denver, for the construction of a custom boat-tailed body.
The body was designed by Ernest H. “Ernie” Niederhut, son of Henry E. Niederhut, who founded the company (originally Niederhut Bros.), with his brother William G. Niederhut, in 1892. According to one document we received with the car, the fenders on the Bonneville Hupp inspired the fenders on the Mormon Meteor, as they cut air resistance and kept salt from spraying the driver.
Once the body of the car was complete, Dr. Knoch set about trying to find a way to modify the engine of his Hupp to reach the fastest speeds possible. He started this by writing to Hupmobile about how he might raise the compression ratio of the engine to 7.5:1.
These early letters from Dr. Knoch to the Hupmobile Motor Car Corporation seem to have been met with confusion, the executives seemingly unaware that Knoch was intending to race at Bonneville. They refer to the car’s performance “at Denver altitude,” referencing the doctor’s home town, and that Knoch’s questions about potentially using multiple carburetors made little sense for a “pleasure car.” Was Knoch being coy as to what he was hoping to do with his Model H? Perhaps that was the case, as it seems the Hupp executives assumed it was still being used as a touring car by a simple country doctor.
Knoch eventually achieved his desired compression ratio through the installation of new pistons heads. This change required an adjustment to the depth of the spark plugs, which further required special aluminum gaskets. Dr. Knoch kept the cylinder bore reading information from October 10, 1934, and October 12, 1934, as well as correspondence from the Ray Day Piston Corporation.
The next challenge was raising the octane of the fuel used in the Hupp, an especially difficult task in an era before modern gasoline. Dr. Knoch sought out fuel additives, such as Ethyl Fluid, developed by the Ethyl Gasoline Company. However, Ethyl executives steered Knoch toward the use of benzol, noting that a 20% benzol-to-gasoline ratio would achieve about 83 octane. Knoch proposed using 90% benzol.
And so he did, and seemingly to great effect. Knoch and his team developed what one Ethyl Gasoline executive called “an ingenious method of operating your cars by bleeding benzol into the carburetor.” The benzol tank that fed this bleed is still part of the car today.
Knoch also wrote to Hupmobile to inquire about twin carburetors, probably seeking to emulate the multi-carb approach of what was probably the world’s most famous Hubmobile, the “Hupp Comet.”
The Comet was a racecar driven by the famous Russell Snowberger. Before driving the Comet, Snowberger entered his own car, a Studebaker, into the Indianapolis 500 and finished 5th in 1931.
This impressive upstart performance caught the attention of executives at Hupmobile, who wanted to promote their cars through involvement in the growing phenomenon of Indy Racing. Hupmobile coaxed Snowberger to pull the Studebaker motor out of his race car and install a Hupmobile H engine, of his design, to race at Indy for the Hupp Corporation. His car was then dubbed the “Hupp Comet.”
But with the deepening of the Great Depression, Hupmobile’s Indianapolis racing endeavors were short lived. At the end of the 1932 season, Russell Snowberger decided to go his own way and returned the engine and all Hupmobile-related parts back to the company.
But the executives at Hupmobile were not about to let a good engine go to waste. Instead, they could sell the engine to Dr. Knoch, this new sort of upstart in Colorado. It would allow them to recoup some of their investment in the Indy team, but more interestingly it would allows them to foster what was essentially an unofficial Hupp racing team at Bonneville.
This was especially interesting for the cash-strapped Hupmobile Motor Car Corporation, as racing at Bonneville wasn’t as stressful as Indy, with its regular schedule of races and the pressure that goes with them. Racing on the Salt Flats was less about drivers racing against each other and more about racing against the bounds of what current engineering and technology made possible.
By helping Knoch, the folks at Hupmobile had a race team that was self-financing and whose losses would go unnoticed, but whose potential wins would give them the headlines they needed to sell cars. This logic lead Hupmobile executives like F. J. Snyder to consistently entertain Dr. Knoch’s continuing stream of requests for special parts and engineering advice.
In 1933 the Hupp Comet motor was sold to Dr. Knoch and installed in the Bonneville Hupp. Knoch put the motor to use, and of course, wrote more letters to Hupp. He now made requests for replacement gaskets from the Victor Gasket Company, who had supplied gaskets for Snowberger’s race team. Eventually he found them, care of the Gambill Motor Company, a Hupp distributor.
Finally, 1935 saw the first run of the Bonneville Hupp at the Salt Flats. According to an extensive write-up in the August 1977 edition of Cars & Parts, later republished in the Hupp Herald, Dr. Knoch himself drove the car to a speed of 136 mph. Photographs taken that day show Augie Duesenberg’s dog sitting in the car, and it is believed that Augie himself timed the car.
But Duesenberg wasn’t the only connection Knoch made with Bonneville royalty in 1935. The Bonneville Hupp was prepared for racing the Salt Flats by Bill Kenz, who was just beginning what would become one of the most illustrious careers in racing.
Kenz went on to partner with Roy Leslie, and together the two established a career in drag racing and midget racing, with a dominating presence at Bonneville. Their “Odd Rod” ran at over 140 mph on the salt flats in 1949 and their later “777 Streamliner,” powered by three flathead eight engines, posted a speed of 261.81 mph in 1956.
The excitement of the 1935 run and the association with the famed Duesenberg brothers pushed Knoch to go even faster. He was finally doing what he wanted to be doing—racing in big leagues. As he began rethinking the car’s design in 1936, Dr. Knoch sought out new gear ratios for the Bonneville Hupp.
Knoch’s original request for a 3:1 ratio was rebuffed by the engineers at Hupmobile, who instead were able to drop his Model H from the standard 53:13 (nearly 4:1) to 3.25:1. This was settled in a slew of technical correspondence in 1937 with letters dating from January 12, January 22, February 11, another from February 11, February 18, and February 19.
Gaskets were then upgraded, supplied by McCord Radiator Company, who produced copper-reinforced gaskets that would hold up better when exposed to high temperatures
The car was run at Bonneville again in 1937. We have several photos from this trip to Bonneville.
After this run, it seemed that the new axle ratio became a cause for concern. The 3.25:1 modified gears provided by Automotive Gear Works of Richmond, Indiana, were overheating when the Hupp ran at high speeds over long periods of time.
In May of 1937, Knoch sought to resolve the overheating problem by seeking advice from Automotive Gear Works, the same company who produced the axle gearing. They recommended using castor oil, rather than using a lead-based lubricant. Knoch also sought advice from Kendall Refining, who was happy to recommend several of its own products.
In September of the same year, Knoch became part of Bonneville history, but perhaps not in the way he imagined. It was at that time that David Abbot “Ab” Jenkins set at 24-hour world speed record of 157.27 mph. Dr. Knoch tended to Jenkins, who was injured partway through the run, having a piece of metal embedded in his arm, which Knoch is quoted as saying barely missed one of Ab’s major blood vessels. Brownie Carslake of Firestone Tire would later thank Dr. Knoch for his assistance, writing, “None of us will ever forget how readily you stepped in and the timely assistance you gave when assistance was really needed.”
Throughout 1938 and 1939, Dr. Knoch appears to have continued his pursuit for speed. He wrote to Schwitzer Cummins about superchargers and was met with some of the skepticism that he was met with in his early letters to Hupp. Lee Oldfiend, a Consulting Engineer at Cummins, reacted to Dr. Knoch’s proposed configuration of a supercharger by writing “such a combination could not be very useful except at speeds close to the peak” and “we should like to discourage you with this project.” Mr. Oldfield also didn’t contact “Mr. Duesenberg” about the proposed configuration, as Dr. Knoch had suggested. Oldfield didn’t realize he was writing to the man who quite possibly saved Ab Jenkins life!
The letter writing went on, and Dr. Knoch received replies from American Bosch regarding a magneto and to Air Associates regarding their Anilol fuel additive. Interestingly, Milton Chapel of Air Associates claimed that hundreds of racecar drivers had adopted Anilol from its introduction to the racing community in October of 1938 to the time of his writing to Dr. Knoch, which was only seven months later.
We don’t know if the supercharger was ever added to the Bonneville Hupp or if Dr. Knoch ran the car with alternate fuels or additives after 1938. Our records drop off after those dates, aside from the documented chain of ownership.
The Bonneville Hupp stayed in Frank’s possession until recently when John Snowberger, Russell Snowberger’s son, purchased the racer in order to turn back the hands of time and restore his father’s 1932 Hupp Comet.
White Glove Collection acquired the body and chassis of the 1930 Hupmobile Bonneville from John Snowberger and has restored it to its 1932 racing configuration, including an original Model H engine.