The march of the pre-war German racing machines was inexorably linked to Adolf Hitler’s rise to power, after the Fascist leader became the country’s chancellor in January 1933. Like many before and since, international sporting success was seen as a means to assert Germany’s status on the international stage and what better tool for the job than motorsport, representing as it does both the heroism of drivers and technological prowess?

At the same time as Hitler’s arrival on the scene, the Association International des Automobile Clubs Reconnus (AIACR) which set international racing regulations, concocted a new grand prix formula for introduction in 1934. In an effort to keep a cap on increasing car performance a maximum vehicle weight of 750kg was set, the rule-makers somewhat naively assuming that this upper limit would rule out large capacity, high power machines. It didn’t.

In Germany, Mercedes was immediately on the case developing a design study for the new formula, but so too was a small company in Stuttgart headed up by the former technical director of Steyr, a certain Ferdinand Porsche. His outfit had been working on road car designs for the Wanderer marque, with Porsche encouraging the company to back a racing effort. However, Wanderer was merged, along with Horch, Audi and DKW to form Auto Union in late 1932, with the new entity initially noncommittal towards racing.

Undeterred, Porsche’s design agency, which included engine specialist Josef Kales; Porsche’s right hand man Karl Rabe; Porsche’s son, Ferdinand aka “Ferry”; and Adolf Rosenberger, a well-heeled amateur racer, penned the outlines of a 750kg car, with financial backing from a friend of Rosenberger.

The group drew up a design for a car that marked a radical departure from what was then the norm; it would be mid-rear engined, with independent suspension all around and a V16 engine producing in the region of 300bhp. The question was, who would pay to build it?

Fortunately, Auto Union’s view of racing as a positive influence firmed up by early 1933, encouraged by the possibility of a racing subsidy from Hitler’s government. Though not a huge sum, the German Ministry of Transport set aside 500,000 Reichsmarks to fund racing development, which was promptly claimed by Mercedes. However, following representations to Hitler by Auto Union chairman Baron Klaus von Oertzen and factory driver Hans Stuck, whom Hitler admired, it was agreed the money would be shared between the two companies. By the end of 1933, Auto Union was testing its debut grand prix machine, dubbed the P-Wagen, in the Eifel mountains replete with its 4.4 litre, supercharged V16, reported at the time by Autocar as having “reputedly the world’s most tremendous exhaust note.”

But why a V16? Porsche’s reasoning had more to do with packaging than the high rpm potential afforded by the use of so many cylinders. The choice of a 45-degree vee angle, coupled with small bore sizes allowed for a very narrow and relatively short engine, which would fit within the (regulation mandated) width of the cockpit, helping to keep frontal area low. It was never intended to run at high rpm, Porsche was after low down grunt and peak power was delivered at just 4500rpm. Due to the low rpm only two valves per cylinder were required and significantly, the use of heavy and complex dual overhead cam heads could be avoided. Instead, all 32 valves were operated by a single, centrally mounted camshaft, actuating the inlet valves via finger followers and the exhausts with pushrods, a layout made possible thanks to the narrow vee angle. The first iteration of the supercharged engine ran 1.66 bar of boost absolute and could muster 295bhp.

Everything about the engine was built to be lightweight, from the cast silicon-aluminium block featuring wet liners to the non-structural sump (the main bearings were supported by substantial webs incorporated into the block casting). Notably, it was also designed with the potential to enlarge the capacity at a later date.