SUPERCHARGERS FOR STOCK MODELS

Evening Star, Issue 22247, 27 January 1936, Page 13

SUPERCHARGERS FOR STOCK MODELS

Superchargers which call be fitted to stock model sports cars are among the many recent technical developments which have reached what is popularly! known as the “ commercial ” stage. With the help of a supercharger the power output is considerably increased at high revolutions, and such equipment, which is now to be found on a few models ns a standard fitting enables much greater speed and acceleration to be obtained from an engine of any given capacity than when the mixture is fed to the cylinders only by the suction of the pistons on intake strokes. . . .

There are, however, several disadvantages which are ordinarily inherent in superchargers. They add to the complexity of the mechanism, are relatively expensive to manufacture, and, as a* rule, have an adverse effect on petrol mileage. Such at least are the charges which might have been brought against niaily of the earlier types, but now improvement of design encouraged by the popularity abroad of,small, fast sports models has resulted in the production of sturdy supercharging attachments, which are not very expensive and can be fitted without the need for radical alterations of the carburetion system.

“ LIGHT-BOOST ” AND POWERFUL TYPES.

Among those _ devices which are known as the “ light-boost ” type is a supercharger marketed in England for the smaller M.G. models. The standard unit, which costs £27, delivers the mixture at a positive pressure of 51b. There is also a more powerful sort which raises the pressure to 101 b to the square inch. In the case of the former no changes in the engine are called for, but with the latter different cylinder gaskets, pistons, and valves are needed. The apparatus is housed beneath the bonnet, at one side of which a small airscoop is provided. In trials made in England with a "P ” type M.G. supplied with this form of blower a speed of almost 84 miles per hour was registered over a “ flying ” distance. A rate of 60 miles per hour from n standing start was reached in 25sec, and it was noted that the betterment of general performance was very pronounced when the engine was “ revving ” at more than 2,500 revolutions per minute, and that normal flexibility in the lower range was in no way impaired.