BMW 328 Mille Miglia Bugelfalte

BMW was actively involved in sports racing in the pre-war years, enjoying considerable successes with its advanced high performance 328. The 328’s success in competition and in the public’s perception established the company’s reputation for lightweight, responsive high performance sporting automobiles. In fact, it made its debut not at an auto show but at the Nürburgring in the Eifelrennen, where in the hands of Ernst Henne it won on its first outing on 14th June 1936.

A series of racing successes followed for BMW in the hands of factory drivers, privateers and team drivers supported by the British importer Frazer Nash.

In autumn 1939, the car was dismantled at the BMW factory’s racing division in Milbertshofen before being extensively re-engineered and used as the basis for even more streamlined bodywork in preparation for the 1940 season and the Mille Miglia in particular. To that end, BMW built both an aerodynamic coupé and this lightweight open roadster.

Its panels were formed over an armature of small diameter tubing, preceding the similar superleggera system patented by Carrozzeria Touring in Milan years later. Welded to the twin tube frame, the body structure lends substantial rigidity to the Bügelfalte’s chassis while weighing just 103 kg. The wheel wells were made of the same lightweight aluminium-magnesium alloy, and the inside panels were partially made of pure magnesium. In fact, the seat frames were pure magnesium as well. This was the absolute cutting edge of racing technology and helped bring the car’s curb weight down to just 725 kgs. An extraordinary achievement, then and now!

The engine itself was completely upgraded in all respects, now producing 130 hp, a full 50 hp more than the standard engine of a road-going 328. A larger oil pan was fitted, as were an additional side-mounted oil cooler, a 100-litre fuel tank and a special air box that helped draw in air at high speed. This motor received a magnesium valve cover and was mated to a strengthened race-ready Hurth transmission with gearbox housing partially made of magnesium, as was the differential with a 3.44:1 gear ratio.

Magnesium was even used in the braking system, comprised of Alfin drum brakes with a Duplex system front and rear. The 17-inch steel disc wheels have riveted light metal rings, and the tyres were specially made by Continental for the Mille Miglia, so the car could go the entire distance without changing tyres. In true racing fashion, the rear leaf spring suspension was adjustable, controlled with additional stabilising bars. Even the hubs were super-light special edition units, as was much of the hardware, aluminium nuts, screw heads and the like.

Following its completion at BMW’s Milbertshofen works, the Bügelfalte BMW was tested on the autobahns near BMW’s Munich headquarters. One can only imagine what contemporary motorists must have thought as this space-age streamliner blasted by at unheard-of speeds!

This car was auctioned off by RM Auctions in May of 2010 at the Grimaldi Forum, Monaco.

130 hp, 1,971 cc inline six-cylinder engine, four-speed manual transmission, independent front suspension with transverse leaf spring, live axle rear suspension with semi-elliptic leaf springs, four-wheel hydraulic drum brakes. Wheelbase: 2,400 mm (94.5")

Source: RM Auctions
Photo Credit: Copyright Peter Raider and BMW Group Archive

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