Duesenberg in motorsport

The Duesenberg brothers began their racing involvement in the early 1900s with four-cylinder engines in Mason automobiles. By 1913, they had formed the Duesenberg Motor Company and shifted focus to high performance engines, including marine and aircraft units during World War I. Their first Indianapolis 500 entry came in 1914, when World War I flying ace Eddie Rickenbacker drove a Duesenberg designed car to a 10th-place finish the first Duesenberg at the Brickyard. In 1919, driver Tommy Milton won the Elgin Trophy in a Duesenberg, and the brothers perfected their signature straight-eight engine design, which emphasized durability and high crankshaft speeds through innovations like shell bearings.^[1]

• The 1924 Duesenberg 122
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  1914 Duesenberg Special
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  1915 Duesenberg „Benedict Special“

For the 1920 racing season, the Duesenbergs developed the Duesenberg 183 Grand Prix (also known as the Duesenberg Straight Eight Racer), a purpose-built open wheel car to compete under the new American Automobile Association (AAA) 183-cubic-inch (3.0 L) displacement limit. Only three examples were built.^[2]

• Engine: 183 cu in (2,999 cc) inline-8, single overhead cam (SOHC), three valves per cylinder
• Bore × stroke: 2.5 in × 4.66 in (63.5 mm × 118.4 mm)
• Power: 114–115 hp (85 kW) @ 4,250 rpm
• Transmission: 3-speed manual
• Brakes: Four-wheel hydraulic (a Duesenberg innovation and first in racing)
• Wheelbase: Approximately 105.5 in (268 cm)
• Weight: ~2,002 lb (908 kg)
• Top speed: Over 100 mph (161 km/h) in period racing trim

The cars featured advanced engineering for the era, including a ladder-frame chassis and exceptional balance. In 1921, four Duesenbergs (three racing) were sent to the French Grand Prix at Le Mans—the first postwar running of the event. Jimmy Murphy drove the No. 12 Murphy Special (a Duesenberg chassis and engine) to victory, becoming the first American car and driver to win a European Grand Prix. One sister car (No. 16, driven by Joe Boyer) retired early but demonstrated the cars' competitiveness. At the 1921 Indianapolis 500, Duesenbergs finished 2nd, 4th, 6th, and 8th. The Murphy Special returned in 1922 to win the Indianapolis 500 outright (with eight of the top ten finishers being Duesenberg-powered or -chassised cars), marking one of the brand's strongest showings. The same car remains the only vehicle to win both the French Grand Prix and the Indianapolis 500.

• The 1921 Duesenberg 183
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Rule changes reduced displacement limits (to 122 cu in / 2.0 L by 1923–1925), prompting further development. The Duesenbergs introduced centrifugal superchargers derived from wartime aero-engine experience in 1924, making them the first to win the Indianapolis 500 with forced induction.^[3]

• Engine: 121.3 cu in (1,988 cc) inline-8, double overhead cam (DOHC) with 2 or 4 valves per cylinder (supercharged versions typically DOHC 2v), centrifugal supercharger
• Power: Significantly higher than naturally aspirated predecessors (exact figures varied by tune; period estimates suggested well over 150 hp)
• Other features: Four wheel hydraulic brakes, lightweight chassis

In 1924, L. L. "Slim" Corum started in a supercharged Duesenberg; Joe Boyer relieved him mid race and drove to victory after multiple lead changes against Miller competitors. This was the first supercharged Indy 500 win.^[4]

Peter DePaolo won in 1925 in a bright yellow supercharged Duesenberg "Banana Wagon," averaging 101.127 mph (162.746 km/h) the first time the 500 was completed in under five hours. Duesenbergs also placed 3rd and 8th that year.^[5]

After a Miller win in the rain-shortened 1926 race, George Souders drove a Duesenberg to victory in 1927. Overall, Duesenberg cars won the Indianapolis 500 outright in 1924, 1925, and 1927 (with the 1922 win on a Duesenberg chassis), while finishing second or third in four other years during the decade.

The Duesenberg straight-eight engines evolved across formulas:

• 183 cu in (1921–1923): SOHC 3v
• 122 cu in (1923–1925): DOHC variants, supercharged options
• Later 91 cu in (1.5 L) adaptations for 1926+ rules.

• The 1924 Duesenberg 122
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The 1927 Duesenberg 91 was a supercharged straight-eight racer built or prepared under the direction of Augie Duesenberg (Fred focused more on the passenger-car side after the 1926 sale to E. L. Cord). It used a compact 91 cubic inch (approximately 1,480–1,490 cc) DOHC inline-8 engine, derived from Duesenberg's earlier successful designs but adapted to the new small displacement rules.

• Engine: 90.3–91.5 cu in (1,480–1,500 cc) inline-8, double overhead cam (DOHC), typically 4 valves per cylinder, centrifugal supercharger
• Bore × stroke: Approximately 2.286 in × 2.750 in (58.1 mm × 69.9 mm)
• Power: Period estimates for competitive supercharged 91s (Miller or Duesenberg) ranged from 155 hp at introduction to over 250 hp at 8,000+ rpm with development; Duesenberg variants were competitive but generally slightly less powerful than the best Miller 91s
• Chassis: Lightweight open-wheel design with four-wheel hydraulic brakes (Duesenberg innovation carried over)
• Weight: Around 1,300–1,500 lb (590–680 kg) range for the formula cars
• Transmission: Multi-speed manual
• Top speed: Capable of well over 140 mph (225 km/h) in tuned form on suitable circuits

In the 1927 Indianapolis 500, rookie driver George Souders piloted a privately entered Duesenberg (often described as a two-year-old or older chassis powered by a ~90–91 cu in DOHC supercharged Duesenberg engine, owned by William S. White). Starting from 22nd position (qualifying speed around 115 mph), Souders drove a steady, solo race without relief drivers—the first to complete the full 500 miles alone since the event's early years. He won by a massive eight lap margin (the largest since 1913) at an average speed of 97.545 mph, finishing well ahead of Miller powered cars in second and beyond. Duesenbergs also took 5th place (Dave Evans). This victory marked Duesenberg's last Indianapolis 500 win and one of the final major successes for the make under the 91 cu in formula.

The 1927 season highlighted Duesenberg's resilience despite financial pressures; the company concentrated efforts on the 500 while Miller cars swept much of the rest of the AAA championship. Supercharged 91s from both makers were engineering marvels, achieving remarkable specific outputs for the era through high crankshaft speeds and advanced supercharging.After 1929, the AAA introduced the "Junk Formula" (1930 onward), which allowed larger stock based or modified engines (up to 366 cu in) without superchargers in an attempt to reduce costs and broaden competition. Duesenberg 91 derived engines were sometimes bored or stroked for these new rules, but factory-level involvement declined sharply after Fred Duesenberg's death in 1932.

• The 1927 Duesenberg 91
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After the passenger-car division was sold to Cord in 1926, Augie Duesenberg continued building and maintaining race cars. Entries competed into the 1930s under the "junk formula" and later rules, sometimes using modified Model A engines or larger displacements, but Miller and Offenhauser engines increasingly dominated. Duesenberg-powered cars appeared in select AAA Championship events, but factory level success waned after Fred Duesenberg's death in a 1932 car accident. Duesenberg innovations straight eight engines, hydraulic brakes, and supercharging directly influenced later American racing and production cars. The brand's racing legacy is preserved in museums such as the Simeone Foundation Automotive Museum (which owns a restored 1921 183) and the Indianapolis Motor Speedway Museum. Surviving examples, including the Murphy Special replicas and 1925 "Banana Wagon" recreations, remain highly prized.

The Duesenberg Type 91 (sometimes referred to as a 1932 grand prix or single-seater variant) was a rare, late-era racing car built or modified by Augie Duesenberg's independent operation after the main company shifted focus. Only a small number (reportedly around seven) of these advanced single-seaters were constructed, primarily for export or international competition as American oval racing moved away from the pure 1.5-liter formula. One of the most famous examples is the car associated with British-American driver Whitney Straight (often called the Whitney Straight Type 91 or ex-Scuderia Ferrari Duesenberg). This machine originated as a Duesenberg-built 91 cu in (or derived) chassis/engine package, later adapted for European-style road circuits. It was sold to Scuderia Ferrari and driven by Count Carlo Felice Trossi in the 1933 Monza Grand Prix (with a larger 4.25-liter Clemons engine installed for that event). Whitney Straight acquired it in 1934 and raced it extensively in Britain.

• Originally a Duesenberg 91 cu in DOHC straight-8 (supercharged in its American racing configuration); later modified with larger engines (e.g., 4¼-liter Clemons) for European events
• Chassis: Lightweight single-seater with advanced suspension and braking for the period
• Performance: On October 13, 1934, at the Brooklands Outer Circuit (a high-speed banked track), Whitney Straight set a Class C lap record of 138.15–138.78 mph (222+ km/h), making it the fourth-fastest car ever around the Outer Circuit at the time. The record stood unbeaten in its class for the remaining years of Brooklands operation.^[6]
• The car was known as a "brute" with challenging handling due to its power-to-weight and chassis flex on rough surfaces, yet Straight demonstrated remarkable skill in taming it.

This Type 91 exemplified Augie Duesenberg's continued innovation in small numbers after the Cord takeover. It bridged American oval racing technology with European Grand Prix efforts but saw limited factory support. The car survives today and has been restored, notably displayed or associated with the Brooklands Museum.

• 1932 Duesenberg Type 91 Whitney Straight
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The 1927 91 victory and the 1932 Type 91's European exploits underscored Duesenberg's engineering prowess even as Miller and later Offenhauser engines took over American racing. Innovations like the straight eight layout, supercharging techniques, and hydraulic brakes influenced both motorsport and production cars (notably the Duesenberg Model J). Surviving examples, including period 91 racers and the Whitney Straight car, are highly valued in collections and museums such as the Indianapolis Motor Speedway Museum and Brooklands.