-By John Engstrom
Normally, the air-fuel mixture is drawn into the engine at atmospheric pressure by the suction created by the pistons. The advantage of supplying a fuel air mixture into the engine under pressure (supercharging) by fully filling the cylinder with the air-fuel charge, will boost the power as much as thirty percent without doing anything else to the engine. It’s more air-fuel mixture in the same amount of space.
Now, how many have seen these superchargers on old foreign cars? Shorrock Superchargers were a common add-on in many British Cars to deliver more horsepower. They were used on MG, Morris, Austin, Sprite, Triumph and even Allard.
They were considered to be the Rolls Royce of superchargers for small bore engines. They were well designed and made of the best materials. Shorrock records include; In 1939 an MG fitted with a Shorrock exceeded 200 MPH. In 1957 a One and a half litter MG driven by the late Sterling Moss broke five international records; including the flying Kilometer at 245.6 MPH. In 1959 a Shorrock equipped Austin Healey Sprite beat 15 international Records and 52 American records with 145.56 MPH. Phil Hill drove a Sprite in the Sebring 12 hour endurance at 138.56 MPH, capturing six new Class E records. Later the Sprite set a flying mile, class E record of 254.53 MPH.
Yikes, 254 MPH in a Sprite !!
They were popular throughout the 30’s, late 40’s, 50’s and 60’s. The company went out of business sometime in the early 70’s.
They are now getting hard to find, but if you find one, they can still be repaired.
The company was launched by Christopher Shorrock in 1934 as the Centric Superchargers Ltd. company. After WWII, the company was renamed the Shorrock Superchargers Ltd. The superchargers were of the fixed vane ( or positive displacement ) type of unit. They featured fixed vanes with a .001 clearance between the vane and the cylinder wall. This way there was no wear on the vanes. The Shorrock name stood for the ultimate in quality and design for all small superchargers.
It seems that one of the family descendents now lives in the area and is a member of the InterMarque. He says that …”We all come from Lancashire on the north west coast of England. Richard de Shorrock was the Norman Lord of the manor at Blackbum around 1100 and many streets, parks are named after him. The Manor is still there.”