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1952 Porsche 356 ‘America Roadster’

Max Hoffman convinced Porsche it needed a lightweight convertible to compete with Jaguar and Austin-Healey.

1952 Porsche 356 ‘America Roadster’

This isn’t technically a Speedster, but the Type 540 (Typ 540 K/9-1 to be very precise) – known more commonly as the America Roadster – started the idea. The American Roadster was the direct predecessor of the Speedster. U.S. importer Max Hoffman convinced Porsche it needed a lightweight convertible to compete with the best from Jaguar and Austin-Healey. It only had an emergency folding roof and could keep up with larger sports cars of the era. But the production methods used to create the America Roadster’s aluminum body proved to be too expensive, and in 1952 Porsche built only 21 units before its discontinuation in 1953. All but one of which were sold in the United States.

At the Paris Motor Show in October 1950, Porsche management held a meeting with American car dealer, Max Hoffman. Hoffman was already the Volkswagen and Jaguar distributor for North America and, following the Paris encounter, he became the Porsche concessionaire too. The US market was central to Porsche’s early success and Hoffman was regarded as something of a visionary back in Stuttgart.

In early 1952, he requested a pared down 356-based car for weekend racers. Hoffman wanted something with a lightweight aluminium body, top specification engine and no frills interior. Porsche reluctantly agreed and the 356 Type 540 America Roadster became the first instance of an outside market dictating a Porsche product. While the standard 356 floorpan and engines could be utilized for the new car, a coachbuilder to manufacture a small run of aluminium bodies would have to be sought.

Porsche decided to commission Glaser Karosserie in Dresden for the job.

In addition to a small batch of aluminium bodies for the America Roadster, Glaser were also contracted to build 250 Cabriolet shells for the regular 356. Porsche’s usual body builder, Reutter (who only worked in steel), were already flat out so it likely seemed prudent to bring in some extra help to meet demand.

Although at first glance the America Roadster resembled any other 356 of the era, there were a multitude of subtle differences. It featured a distinct hump-backed appearance, simplified detachable two-piece windscreen and lowered doors. The rear quarters were intricately curved and the engine cover was moved further up than on the standard car. A rudimentary hood was supplied, but the America Roadster was not created to be a practical all-weather sports car; Porsche did not even supply side windows. Most examples came with leather retaining straps for the front lid. Bumpers with overriders were also usually fitted.

Like the 356, the America Roadster was designed by Erwin Komenda. As mentioned, it was uniquely fabricated from lightweight aluminium whereas series production variants wore steel bodies. Customers that wanted to race their cars could save around 50kg by removing the windscreen, hub caps, hood, jack, spare wheel and boot lining.

Each America Roadster was based on a standard steel 356 Cabriolet floorpan. Suspension was fully independent via transverse torsion bars and trailing arms with additional swing axles at the rear. Telescopic dampers were fitted all round. The hydraulic 230mm drum brakes were supplied by Lockheed. 3.25-inch wide wheels were ventilated to assist brake cooling. A standard 52-litre fuel tank was located under the front lid along with a spare wheel and battery.

In the engine bay was Porsche’s flagship Type 527 engine which had been introduced back in October 1951. A 1.5-litre air-cooled Flat 4, it featured an alloy block and head, Hirth roller bearing crankshaft, hot camshaft, alloy cylinder barrels, chrome-plated bores and sodium-filled valves to improve heat dissipation. Displacement was 1488cc thanks to a bore and stroke of 60mm and 74mm respectively. A compression ratio of 7.0:1 was employed along with two Solex 40 PBIC carburettors. Peak output was 70bhp at 5000rpm and 75lb-ft at 3000rpm. Transmission was via a non-synchromesh four-speed Volkswagen gearbox with single dry plate Fichtel & Sachs clutch. In road-going trim complete with accessories, the America Roadster weighed in at 705kg. This compared to 810kg for the standard Cabriolet. Top speed was 112 mph and 0-62 mph took 9.3 seconds.

One of the earliest examples (chassis 10465) was sold to Briggs Cunningham who along with his son (Briggs Cunningham Jr.) and Phil Walters, raced the car throughout 1952. Others were sold to and raced by LeRoy Thorpe, Bill Lloyd and John Crean.

In October 1952, the new Type 528 engine was introduced. It came with a higher 8.2:1 compression ratio and produced 70bhp at 5500rpm. The torque rating was 80lb-ft at 3600rpm.

Because it was priced around 20% higher than a 356 Cabriolet, demand for the America Roadster was subdued. In December 1952, after Glaser had produced just 16 America Roadsters (plus around 80 Cabriolets), the firm went out of business. The America Roadster took much longer to build than anticipated and Glaser lost money on every car they produced. Most America Roadsters were exported to the USA and the majority were completed as road cars.

Although the America Roadster turned out to be a commercial failure, Max Hoffman was convinced there was still a market for a simplified and lightened 356. He continued to lobby Porsche for such a car and, in September 1954 the 356 Speedster was launched at the Frankfurt Motor Show. The Speedster went on to become an enormous success. It not only won hundreds of races but went down in history as one of Porsche’s most iconic models.

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Specs & Performance

type Series Production Car
built at Germany
coachbuilder Heuer/Gläser
production 21
engine Air Cooled Flat-4
displacement 1488 cc / 90.8 in³
compression 8.2:1
power 52.2 kw / 70 bhp @ 5000 rpm
specific output 47.04 bhp per litre
bhp/weight 115.7 bhp per tonne
driven wheels Rear Engine / RWD
curb weight 605 kg / 1334 lbs
length 3850 mm / 151.6 in
top speed ~180 kph / 111.8 mph

 

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