Thank Frankel it's Friday: The coolest car at FOS was a diesel

But there it was. As I turned around at the top of the Hill I was summoned to park directly behind the Cummins Diesel Special. This is a car that’s fascinated me for almost as long as I’ve been fascinated by cars because it did something all conventional thinking thought entirely impossible. At the 1952 Indianapolis 500, it became the first and – until Audi embarked on its sports prototype diesel programme in 2006 – only car to take pole position at one of the world’s greatest motor races.

Clessie Cummins was not just a great engineer, he was a born publicist, well aware of the benefits a successful Indycar programme would have on his diesel engine business. So aware indeed that he first entered a diesel-powered car for the 500 in 1931, Dave Evan’s Duesenberg rumbling around the Brickyard for the duration, finishing a respectable 13^th partly because he had no need to refuel. In 1934, a two-stroke diesel of his finished 12^th, to this day the highest place finish of any diesel car in the race.

The next attempt came in 1950 with a car called the Green Hornet powered by a supercharged Cummins truck engine, which proved heavy, slow and unreliable. But two years later they’d be back with a far more convincing race car.

The Cummins Diesel Special is fascinating and not just because it filled from the black pump. Built by Kurtis around a highly modified Kurtis Kraft chassis, it is claimed also to be the first Indycar to be developed with the use of proper wind tunnel facilities. The results of those tests meant its 6.6-litre engine was laid almost on its side to radically lower the car’s centre of gravity. And that engine was something else: the rules allowed its capacity to be almost half as large again as the biggest normally aspirated petrol motors in addition to which forced induction could be added. But diesel engines are massively heavy, especially those designed to power trucks, so Cummins cast this one in aluminium with a magnesium crankcase to effectively halve its mass. Then a new-fangled contraption then called a turbocharger was added, making far more power than the conventionally supercharged 1950 car. Around 380bhp we believe. It was to be driven by the well known and respected Fred Agabashian.

And that engine was something else: the rules allowed its capacity to be almost half as large again as the biggest normally aspirated petrol motors in addition to which forced induction could be added. But diesel engines are massively heavy, especially those designed to power trucks, so Cummins cast this one in aluminium with a magnesium crankcase to effectively halve its mass. Then a new-fangled contraption then called a turbocharger was added, making far more power than the conventionally supercharged 1950 car. Around 380bhp we believe. It was to be driven by the well known and respected Fred Agabashian.

The Cummins team knew they had a potentially winning car on their hands but were terrified that the car’s speed in the practice sessions would be so great the rules would be changed to outlaw it or clip its wings. So Agabashian simply tootled around in the weeks running up to the race, never running close to flat out. After qualifying, nothing could be done to slow it down.

It had long been believed that 1952 would be a quick year at Indy and so it proved. But none went so quick as Agabashian whose four-lap average was over 138mph, raising the mark set the previous year at 136.5mph. Pole was duly claimed. To put its speed into perspective, Ascari’s works 4.5-litre V12 Ferrari 375 only managed 134.3mph. 

The race, by contrast, was something of an anti-climax. Fast though the Cummins was flat out, it could not accelerate anything like as fast as the petrol cars and by the time it was up to speed, Agabashian had been overtaken by a third of the field. Tyre concerns meant that despite the fact the car could do the race on a single tank of heating oil, he started with a much lighter load and planned to stop at half distance for fresh rubber, so he set about working his way back through the field, eventually reaching fifth position. But the car never made it to its stop: after 70 laps black smoke started pouring out of the engine, the turbo having overheated when debris from the track blocked its intake tract. It never raced again. 

But that at least means the car seen at Goodwood last weekend is effectively 100 per cent original. It makes a great noise too, which I’d not necessarily expected. Indeed the only thing I didn’t like at all about it was having to follow it back down the hill: even at 30mph the fumes coming out the back were sufficient for me to drop back 100 yards so I could breathe properly. Quite what it would have been like to be in its slipstream at Indy as it went full throttle at nearly 140mph I can scarcely imagine.