1931 Bentley 4 1/2 Litre Supercharged 'Blower' Sports Tourer

After a brutal but heroic 8th Place in the 1928 German Grand Prix, Sir Henry “Tim” Birkin was convinced that the Bentley 4 ½ Litre could be substantially more competitive through supercharging. Alfa Romeo, Bugatti, and Mercedes- Benz were all contenders in international events with blown powerplants, and supercharging appeared to be the key to their success.

W.O. Bentley, however, was firmly against supercharging his cars. His racing strategy was based on endurance and reliability, with the result that Bentleys often pushed hard at the onset of a race, forcing the supercharged competitors to break; easy victory then ensued.

In order to make his dream of a supercharged Bentley 4½ Litre a reality, Birkin had to find outside help. For the supercharger itself, Birkin turned to Amherst Villiers, made famous by the Vauxhall Villiers Special. Despite W.O.’s opposition to superchargers, Birkin was able to enter an agreement with Villiers and Bentley Motors thanks to the support of Woolf Barnato, who at the time controlled much of Bentley’s activities.

In order to run at Le Mans, Birkin’s supercharged 4½ Litre required use of a standard production model, which W.O. apprehensively approved. The design of the supercharger was left to Villiers, but the parameters were set: the Blower had to be driven off the crankshaft and, therefore, mounted in front of the engine. Immediate deficiencies were noted, and the subsequent development of the “heavy crank” 4 ½-litre block ensued.

Eventually, the design was completed and tested. Although Birkin failed to compete in the 24 Hours of Le Mans with his two intended supercharged cars that year, June 1929 saw the first-ever competitive outing for a “Blower” Bentley, and July marked the supercharged car’s first podium finish.

That same year, two production Blowers appeared on the stand at the Olympia Motor Show. By 1930, production Blowers were being delivered to enthusiastic new customers. In April 1930, The Motor published the first road test of the 4 ½ Litre Supercharged, which opens with praise for Bentley’s latest creation:

“The recipe is as follows: - Take a sturdy chassis, install an engine rated at 25 h.p., add a supercharger, fit an open body, wings, and windscreen, and make the complete vehicle have a speed range of from 9 m.p.h. to 103 m.p.h. on top gear. Do all these things and you will have arrived about half-way towards the achievement which the 4 ½-litre Bentley represents. Only half-way, because you have yet to make your car its equal as regards other important attributes, such as roadholding, gear-changing, steering and braking…”

In the end, a total of 50 production Blowers were built over a two-year period – and with that benchmark, Birkin had met the Automobile Club de l’Ouest requirements to compete at Le Mans.

Chassis MS3927 hails from the second batch of 25 cars built by Birkin, which are identifiable by the ribbed supercharger casings protruding from the front of the car. MS3927 was produced early in this series, before the cars became more challenging to sell, and while they were still equipped with the true sporting lightweight bodies. Significantly, this example has also retained the original body from new, making it one of only a third of such cars extant. This Blower has remained in the public eye throughout its life, its lineage easily traceable through factory, coachbuilder, and club records, which have all been condensed into a definitive report by marque expert Dr. Clare Hay.

This supercharged Bentley was supplied to Vanden Plas on February 11, 1931. The coachbuilder bodied the car with the most up-to-date sports touring bodywork, paneled in aluminum. The Vanden Plas order lists the particularly appealing feature of Le Mans-type bucket seats, designed to enhance the true “Bentley Boy” driving experience. Body 1723 was originally painted in striking raven black with a rich red leather trim.

The finished automobile was delivered to Bentley Motors Cork Street showrooms and registered for the road with the London plate “GP1993.” Jack Barclay of Berkeley Square secured the sale of the new Blower to O.D. Winterbottom of Newbury, for whom it was an upgrade from the stock 4 ½ Litre in which he had covered 30,000 miles in over the preceding two years, and traded in against the purchase.

Mr. Winterbottom kept MS3927 for seven years before the car passed to its next custodian, F. W. Ball of Chelsea, who also acquired the car from Jack Barclay. The last owner before the war was Captain P.G. Ashton, based on the Isle of Wight, who acquired the Blower in 1939.

Just after the war ended, Michael Crowley-Milling, the longtime owner of a Nuvolari Alfa Romeo 8C 2300, briefly owned the Blower before it passed through a series of owners that included Ben H. Bowring, who was particularly keen on racing the car. Reflecting the fashion of the day, Mr. Bowring and other successive owners progressively chose to add some of the classic Birkin-esque Le Mans-style features. During this period, the Blower gained a large Le Mans tank and drilled handbrake lever, while the alloy bodywork was covered in dark green fabric. A C-Type gearbox replaced the original for a time and the numbered crankcase was replaced with another original Blower Bentley unit (confirmed by its SM prefix), then stamped as MS3930 to match its original. Although sometimes campaigned in unblown form, its original supercharger, casing no. 127, has remained fitted to this day.

The car remained in the UK until the early 1980s, when owner Sam Ornstein of New Jersey shipped the car to the US. Mr. Ornstein retained the Blower until 1993, when it passed into one of America’s foremost collections of its day, maintained by Henry Petronis of Maryland, who enjoyed the Bentley for 20 years. The car briefly returned to ownership in the UK before being acquired by the current custodian.

Before bringing it to the US, the consignor commissioned the highly regarded specialists at VBE Engineering to rebuild the Bentley’s mechanicals. During this service, the gearbox change was corrected, and the car was fitted with the stronger D-Type gearbox – the unit from the very next supercharged production car, MS3928.

With this work completed, the Blower was exercised regularly on events such as the Colorado Grand. In preparation for a showing at Pebble Beach, the owner turned to Jeff McDonald’s team at McDonald Vintage Restoration in Candby, Oregon, whose workmanship on Rolls-Royce and Bentleys has consistently garnered major concours awards. The refurbishment respected this Blower’s intrinsic authenticity and utilized sister car MS3926, owned by Dr. Fred Simeone, to ensure accuracy in the details. The green fabric was removed from its exterior, the bodywork restored, and the color returned to its original black over red palette. As a testament to the quality and exacting detail of this restoration, the Bentley won its class at Pebble Beach in 2022. Its use since has been regular and careful, and the car continues to present beautifully.

A supercar of its day, Birkin’s Supercharged Bentleys are one of the greatest statements of brazen power and presence in motoring ever built. Rarely for a Vintage Bentley, and particularly a Blower, this exceptional car stands today much as it left Bentley Motors, retaining its original Vanden Plas coachwork, Le Mans seats, and most of its original running gear. A sterling, blue-chip example, this Bentley offers an exceptional chance to experience this legendary model on fast road tours or in concours competition.