The Powerplus is a design of supercharger that was used to boost the performance of car engines in the 1930s. It is a mechanically driven positive displacement pump, operating on the sliding-vane principle.
The Powerplus is a design of supercharger that was used to boost the performance of car engines in the 1930s. It is a mechanically driven positive displacement pump, operating on the sliding-vane principle.
Powerplus is best known through its use on some MG cars of the 1930s. MG specialised in small, lightweight "Midget" cars. Use of supercharging allowed engines of under 750 cc, 850 cc or 1,100 cc to generate competitive amounts of power, whilst still remaining in these small-engine classes.
The Powerplus design was the invention of Captain George Eyston, the land speed record holder. Supercharging first appeared on production MGs with the C type or Montlhéry Midget, inspired by Eyston's EX120 record-breaker of 1930 – the first 750 cc car to break 100 mph. [2]
In the 850 cc class, the 846 cc J3 and the rare (only nine were built) pure-racing J4 of 1932 used the Powerplus. All of MG's superchargers were mounted ahead of and roughly in-line with the crankshaft, between the chassis dumb irons [ definition needed ]. The valance here was given a central bulge, capped with MG's octagon badge. The carburettor was a single large SU, mounted upstream of the blower for suck-through operation.
Perhaps the most famous of all supercharged MGs was the 1,087 cc K3 Magnette. Eyston was also a noted racer of MGs, particularly his K3 Magnette in the 1933 Isle of Man and 1934 Northern Ireland Tourist Trophy races [3] and the Mille Miglia [4] (both reprinted in [5] ) Although these were not intended as everyday road cars, MG set out to produce competitive 'clubman's' racing cars at an affordable production-line price. In 1934 a K3 Magnette with racing bodywork and a pre-selector gearbox cost £795, around twice the price of the Magnette saloons. [6]
Eyston also held many other patents related to similar pumps.
The innovation of the Powerplus was to take the sliding-vane design and to address its main drawbacks. Although the simple sliding-vane design is straightforward to manufacture, having simply shaped component parts, the spring-loaded vanes rub on the housing and this friction requires lubrication. In the 1920s, it was common for supercharged cars to have large consumable oil tanks mounted alongside the supercharger. Their HC exhaust emissions are not recorded.
By adding a set of eccentrics and guide slots to the axle of the supercharger, the Powerplus actively controls the position of these vanes, such that they maintain a constant small clearance from the walls of the housing. This is enough spacing to avoid friction, but close enough to keep pumping efficient. [1]
The obvious advantage of the Powerplus over the Roots was avoidance of the need to machine the complex-shaped rotors. With the manufacturing technology of 1930, this was a serious consideration. Eyston himself already held patents related to these manufacturing difficulties. [8]
The problem with Powerplus was firstly its complexity. Although each component was of simple form, there was some number of them, including a separate Bosch oil pump. This reduced reliability, compared to the simplicity of a Roots (once manufactured).
Secondly, studies by NACA revealed that the Powerplus was less efficient than the Roots, i.e., more power was required to drive it. This was most pronounced at low-pressure differences. [1] Where out-and-out performance was crucial, the Powerplus was competitive. However it was not likely to be preferred where efficiency or reduced fuel consumption were the deciding factors.
The Roots blower is a positive displacement lobe pump which operates by pumping a fluid with a pair of meshing lobes resembling a set of stretched gears. Fluid is trapped in pockets surrounding the lobes and carried from the intake side to the exhaust.
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The Lancia Delta S4 is a Group B rally car manufactured by the Italian car company Lancia. The Delta S4 competed in the World Rally Championship in 1985 and 1986, until Group B class was disbanded and the cars were eventually banned from competition completely by European sanctioning body FIA. The car replaced, and was an evolution of the 037. The S4 took full advantage of the Group B regulations, and featured a midship-mounted engine and all-wheel drive for superior traction on loose surfaces.
The MG Y-Type is an automobile produced by MG in England from 1947 to 1953. It was offered in four-door saloon and limited production open four-seat tourer versions.
The MG P-type is a sports car that was produced by MG from 1934 to 1936. This 2-door sports car used an updated version of the Wolseley Motors-designed and made overhead camshaft, crossflow engine, used in the 1928 Morris Minor and previously fitted in the J-type Midget of 1932 to 1934, driving the rear wheels through a four-speed non-synchromesh gearbox. The chassis was a strengthened and slightly longer version of that used in the J-type with suspension by half-elliptic springs all round with rigid front and rear axles. Steering was initially by a Marles Weller and later a Bishop Cam system. The two-seat car had a wheelbase of 87 inches (2210 mm) and a track of 42 in (1,100 mm). Most cars were open two-seaters, but streamlined Airline coupé bodies were also made. The P-type was also available as a four-seater, a car that suffered from a lack of power and poor rear ground clearance. Whereas J, K and L-type MGs differentiated between versions with the use of numbers, with 1 indicating a four-seater and 2 a two-seater, this was not the case with the P-type, and there is no clue to the type in the name.
The MG J-type is a sports car that was produced by MG from 1932 to 1934. This 2-door sports car used an updated version of the overhead camshaft, crossflow engine, used in the 1928 Morris Minor and Wolseley 10 and previously fitted in the MG M-type Midget of 1929 to 1932, driving the rear wheels through a four-speed non-synchromesh gearbox. The chassis was from the D-Type with suspension by half-elliptic springs and Hartford friction shock-absorbers all round with rigid front and rear axles. The car had a wheelbase of 86 in (2,184 mm) and a track of 42 in (1,067 mm). Most cars were open two-seaters, but a closed salonette version of the J1 was also made, and some chassis were supplied to external coachbuilders. The open cars can be distinguished from the M type by having cut-away tops to the doors.
A rotary vane pump is a type of positive-displacement pump that consists of vanes mounted to a rotor that rotates inside a cavity. In some cases these vanes can have variable length and/or be tensioned to maintain contact with the walls as the pump rotates.
The MG C-type is a sports car that was produced by MG from 1931 to 1932. It was designed for competition use and based on the M-Type Midget. A special car, EX120 had been developed from the M-Type for George Eyston to make an attempt on the 750 cc class 24-hour record at Autodrome de Montlhéry in France. The attempt was successful and a series of replica cars were made which became the C-Type.
Kleemann A/S is an after-market tuning company for Mercedes-Benz sports cars, sedans, and SUVs headquartered in Farum, Denmark. Recently, they have begun producing performance supercharging systems for Audi, BMW, and Porsche.
The 1935 24 Hours of Le Mans was the 13th Grand Prix of Endurance. It took place at the Circuit de la Sarthe on 15 and 16 June 1935. The race was won by Johnny Hindmarsh and Luis Fontés in a British Lagonda, breaking the run of four consecutive Alfa Romeo victories. A record number of 58 starters included a record number of British cars, at 37, dominating the smaller classes. Another notable point of the entry was four all-female cars, and a Le Mans record of ten women competing.
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Captain George Edward Thomas Eyston MC OBE was a British engineer, inventor, and racing driver best known for breaking the land speed record three times between 1937 and 1939.
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The Zoller supercharger was a vane-type supercharger created by Arnold Zoller (1882-1934) who had patents regarding supercharging engines before WW1. The Zoller supercharger was popular in the 1920s and 1930s.
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