Reviewed by Unique Cars and Parts
Our Rating: 5
As The War Clouds Gathered
In the 1930s, as the war clouds were gathering and Germany could boast the most advanced road system in the world, several European manufacturers started thinking about building super cars to make full use of these new super roads. Mercedes used raw power and cubic inches to push its barn-door radiators through the air at high speed, and BMW designed a streamlined "autobahn special" for release in 1936.
Like many political plans BMW's 335 fell behind schedule but the wonder is that such cars were built in the first place. German prestige reasons apart, high speed cars certainly were not needed by the time Adler, Tatra and BMW built them just before the outbreak of the war. Today it is the BMW 335 that most agree is the original "autobahn special" - but strangely if you consider what was written in the 335 handbook the myth does not match the reality.
Designed to Break The Law
BMW explained in their handbook that the 335 could indeed achieve 110 km/h in third gear, which was the one considered the most appropriate for normal driving, and it could even do 145 km/h in top - a special autobahn cog. However new owners were warned that not even the all-day cruise maximum of 135 km/h was actually allowed. The problem was, at the time Germany's legal speed limit was a modest 100 km/h.
Legal requirements aside, the BMW 335 was at home on the autobahn thanks to the tall diff gearing fitted. Pre-war fuel and tyre scarcities didn't encourage high-speed excesses. Put it another way; the almost-forgotten BMW 335 arrived just three years later than its fathers had planned, on open roads which were about to be turned to other uses. Planned for 1936/1937 the first 335 year of any consequence was 1939 because BMW couldn't get any 135 km/h tyres before that. In fact it couldn't get them in 1939 either but buyers got a certificate allowing them to buy a set of proper rubber at a pre-determined price - "when available".
An Utterly Brilliant 3.5 Litre Straight Six
If the 335 didn't appear until the war was on, it also confounded the state rules on private car construction and was built in small numbers as late as 1941. The biggest production engine BMW had built to the late 1970s was not bothered by rules or rationale. The 335 was powered by an utterly brilliant 3.5 litre straight six - and even 30 years after it made its appearance, BMW were producing the slightly smaller 3.3 litre straight six which only just edged it out in performance. Originally the idea was to produce an even bigger six for export - in conjunction with Frazer Nash in Britain.
The 335 was announced within Germany as a car for export markets. On the other hand BMW soon discovered the UK were not all that keen on a big six either, which may be another reason the 335 was delayed for three years. The first test cars with this pushrod engine were running day and night in 1936 to test high-speed durability. Then Fritz Fiedler, the father of the 335. realised he was building a car for the home market which in ?39 had little inclination for an all-new automobile
. So BMW took a 326 production sedan and moved it up-market in typical fashion, building a machine to siphon off the lesser Mercedes owners who wanted speed with less bulk.
Some 10 cm was added to a 326 box-member frame which was stiffened as well. Suspension
, from the same source, consisted of a transverse leaf spring
in front with lower arm and shocks, a beam axle in back with longitudinal torsion bars
and in honor of the considerably greater power the four drum brakes
were given ribs. BMW were obviously seeking a grand tourer image, the all-day racer, and that meant a lot more engine than the common two litre. Both bore and stroke were enlarged (to 82 x 110 mm) and the cam-in-block was to be driven by noiseless gears rather than a chain, a feature which gave teething problems.
The Autobahn Cog
Fiedler even experimented with an alloy head like his sports 328 but settled for cast iron. BMW was obviously scared of extended freeway use because the radiator was big enough for two engines of the size and an oil cooler was optional. But power was a real 67 kW (90 bhp) at 3400 rpm and its all-day cruise speed (135 km/h) required only 2900 rpm. A pedal stop signalled this cruise pace. Mostly BMW was very, very careful to gear the machine so you could hardly over-extend it down the new autobahns. While top gear, the "autobahn" cog, was only 1:1, the final drive was 2.9. You get an understanding of how important that was, when you compare it to the 4.87 for the 326, or even the 3.9 for the 327/328.
Only a power to weight of 10.7 kilograms per kilowatt gave the 335 any kind of decent acceleration. The car would keep up with normal traffic easily - it was elastic as hell with such a long stroke. Adding them all together BMW only built 401 of its largest-ever car and that included 17 delivered as bare chassis. Sedans were the most popular (233), two-door cabriolets next and the four-door with Authenreith bodywork
a relative rarity - 40 of these were built, half in 1939.
Then, as now, with fuel consumption a looming problem for Germans, BMW made much of the 7.2 km/litre at a steady 97 km/h, the German norm. That gave a very reasonable range with its 65 litre tank, which was filled through the locking flap in the hub of the spare wheel. While the 335 was hardly the streamliner the Kamm-tailed Brescia Mille-Miglia
machine would have been, just fairing in the headlamps was a major step. For instance, taking free-standing lamps off a 326 was worth a 9.6 percent improvement in aerodynamics and that sort of thinking led to the 335.
To prove the real value of this willing engine BMW ran one 335 sports down the autobahn in 1940 for a claimed top speed of 253 km/h when it was playing with fuel injection. It's a shame it didn't have the dies to put this engine into the first big postwar machine, the 500, which sagged under two litres in 1953
. Of course most BMW 335's were lost during the war, as they were commonly put into service by higher ranking OKW officers. We believe only a handfull survive - but we have no definitive numbers.