Oil‑burner at the Brickyard: Kurtis‑Kraft Cummins Diesel Special

It’s the perfect ecosystem-come-melting-pot, therefore, for something like the Kurtis-Kraft Cummins Diesel Special to sprout. The ‘50s had to be one of the most developmentally lucrative periods in the history of motorsport. The world was shaken, battered and bruised by war, determined to forge better lives for all and blossoming economically as international trade exploded. The pot of cash and hunger for growth that was the bow-wave of post-war recovery swept all industries and with innovative products being produced in unprecedented numbers that needed to be sold, concepts needed to be proven. Where else other than the racetrack does automotive technology prove its chops?

Technical challenges forced innovation. The high centre of gravity that was the 1950 car’s Achilles heel meant that the Cummins 6.6-litre commercial engine had to be laid on its side – the happy side-effect of which was a left-hand weight bias for the left-turn-only machine. It was the first car to race at Indy to feature an exhaust-fed turbocharger, as well as the first car to be tested in a wind tunnel. Driver-activated radiator shutters were developed such that a boost of 18 horsepower could be accrued with their operation. The newly developed layout made it the lowest car on the grid, too. The car was heavy (in spite of a lightweight alloy block) but it was slippery and very powerful with the monstrous lump good for over 400bhp. Cummins had proven the advantages of diesel at Indy before in 1931 when a car went for the full 500 laps without a pit stop. They would move to avenge their fateful 1950 attempt in ‘52 with the game-changing new car. 

Don Cummins had designs on San Francisco’s 32-year-old race ace Freddie Agabashian to pilot but it was a difficult sell. When approached, Freddie was sceptical of the car’s weight and overall competitiveness. On a drive out around Indy with Freddie, Don had a point to prove. He stopped the car, pulled a 5-inch Coca Cola crate out of the boot and set it on the ground outside the car upside down. He gestured for Freddie to sit, following “That’s all the farther you’ll be riding above the pavement in a new roadster”. Convinced of the innovations the new car would bring to the fight, Freddie was sold.

Today it feels like claims that racing was better in the “good old days” are a bit clichéd, but if anything hammers the point home, it’s reports of Freddie’s Indy qualifying runs. The then-revolutionary but still-primitive turbocharging technology meant that it was difficult to keep it on boost. That meant that Freddie had to keep it flat through the turns. The only way to keep on the pace and not run off was to pitch it sideways. Every turn Freddie would stand on the power and execute corner-long slides, controlling the car under the power he so needed to maintain. The result? Pole-position for the start of the race, a record Indy qualifying speed of 138mph and an utterly decimated set of quali’ run rubbers.

The race itself was a less successful affair from the get-go, with a botched race-start leaving the Cummins 12 cars back, though Freddie would quickly begin clawing it back with his unprecedented average race speed of 130mph. The Cummins was proving its chops but unbeknown to the team or Freddie, the car was slowly losing power due to tyre debris blocking the turbo inlet. Gradually, power was lost over a series of laps before it gave up completely come lap 72. A crying shame as the victory car and driver deserved slipped away but the prowess of the car and the innovations its development brought to bear were already proven. Thus, in spite of its loss, the car remains a legend of Indy history.

Today it spends most of its time in the foyer of Cummins’ global corporate headquarters in Columbus, Indiana. Can anyone say race on Sunday, sell on… the next five decades? It ventured out in public in 1999 at FOS and has since done one private corporate event. FOS 2017 is this car’s first public appearance this side of the millennium. What a pleasure it was to have it here and see it in action.

Photography by Tom Shaxson, Drew Gibson and Jochen Van Cauwenberge