SPEED SIX CONTINUATION SERIES: Speed Six Car Zero
With drivers like Woolf Barnato, Sir Henry ‘Tim’ Birkin, and Glen Kidston at the wheel, the Speed Six, a high-performance variant of the 6½ Litre, became the most successful racing Bentley ever. It won Le Mans in 1929 and 1930.
W.O. Bentley disagreed with Tim Birkin’s belief that supercharging is the best approach to enhancing power and instead advocated for increasing capacity. So he made a new, bigger engine to replace the 4.2 litres. His new straight-six engine had a diameter of 100 mm and a stroke of 140 mm, giving it a capacity of about 6.6 litres. The 6½ liter engine produced 147 horsepower at 3500 rpm when equipped with a single Smiths five-jet carburetor, dual magnetos, and a compression ratio of 4.4:1. The Cricklewood, North London, plant where 362 were produced used chassis of varying lengths to accommodate the various body styles ordered by customers.
In 1928, a sportier variant of the 6½ Litre, the Speed Six chassis, was released. The engine was upgraded to produce 180 horsepower by installing dual SU carburetors, increasing the compression ratio, and installing a high-performance camshaft. Between 1928 and 1930, 182 Speed Six models were produced, all of which rode on a 134-inch chassis frame used for the factory racing cars.
In its racing configuration, the Speed Six’s engine was upgraded to a 6.1:1 compression ratio and 200 horsepower. The 1929 triumph at Le Mans established a new standard of superiority at the event, and the 1930 victory solidified the Speed Six’s position in Bentley history. Woolf Barnato and Sir Henry ‘Tim’ Birkin piloted a Speed Six to the lead and kept it till the finish line, followed by three more Bentleys. Birkin shaved 46 seconds off the previous lap record and averaged 83 miles per hour to create a new mark of 7:21, and he also set a new record for mileage by travelling 2,844 kilometers. It took over 30 years before any manufacturer was able to dominate like that at Le Mans.
Bentley will keep the latest Speed Six (Car Zero) in reserve until after the production of 12 client vehicles (which are all sold out) has been completed so that it can be utilised in a development programme that includes real-world durability and track-based testing.
More than just a reproduction, a continuation automobile is constructed according to the same blueprints and manufacturing methods as the model that started it all. Mulliner, Bentley’s custom and coachbuilding business, built the first pre-war continuation, the Blower Continuation Series, and now they’ve created the second, the Speed Six.
An extensive study was done to guarantee the accuracy and authenticity of the Speed Six, with special attention paid to the actual vehicles’ specifications and configuration during the 1930 24 Hours of Le Mans. We utilised as many of the original designs as we could find; the WO Bentley Memorial Foundation provided us with copies of about 80% of the originals. The designs have been augmented with information from the Bentley Heritage Collection’s 1930 Speed Six and the original 1930 Le Mans racer, Old Number 3, as well as authentic mechanic’s notes documenting the alterations between the 1929 and 1930 races.
The development of the new 6.1-litre, six-cylinder racing standard engine has required the development of more than 600 new components. Dyno testing of the initial engines has shown that they are capable of producing 205 bhp at peak, which is within 5 bhp of the power output of the original race-tuned engines from 1930.
Authentic materials, including those used on the Blower Continuation Series, have been repurposed for use in the Speed Six’s trim. In order to provide five original-era Parsons exterior colours, the Mulliner team went back to the National Motor Museum archives in Beaulieu, Hampshire. Parsons Napier Green covers the outside of the Speed Six Car Zero, while Tan leather lines the inside.
The Speed Six Car Zero was hand-assembled by a team of Mulliner’s most talented craftsmen and engineers over the course of 10 months. Craftspeople with decades of expertise have worked with newer generations in the creation of the Speed Six programme, much like in the Blower Continuation Series, in order to pass on both contemporary and traditional coachbuilding techniques. The entire vehicle was handcrafted in the Mulliner department at Bentley’s Dream Factory in Crewe, and the result is a stunning work of art.
Customers will have the opportunity to go into further depth regarding their specifications during personal commissioning meetings spread out over the following six months. The second prototype vehicle, Speed Six Factory Works, will provide customers with a personalised fitting service to tailor the interior of their vehicle to their own preferences in terms of space and luxury.
The validation programme for the Speed Six Car Zero is comparable to that for the Blower Car Zero and will include real-world mileage accumulation and two race simulations.
Now that the Car Zero has been built, a series of real-world durability tests will get underway. The 8,000 kilometres of track driving in the test programme are meant to simulate 35,000 kilometres of actual road travel. Future customers can be certain that their vehicles have been put through rigorous testing, including intervals of lengthening time and rising speeds.
In October of this year, production of the first of 12 client cars began; by the end of 2025, the entire series will have been finished.
