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A PARTICULAR SYSTEM There are various ways of compressing the mixture, Judson's way is of sliding blades type. Here, the mixture air-gas is compressed thanks to a serie of four rectractable blades mounted on a excentered hub. When the hub turns, the blades get centrifugal, perfectly gas-tightening the system. The free volume in which the mixture has entered is little by little reduced, thus compressing the later and finally blowing within the admission pipe (see sketch). The gas expand slightly at that moment, the temperature remains relatively low, more especially as the blower rotation is normally identical to the engine's one, while in other systems of blowers, it can be overdrove thanks to the use if a small diameter pulley.

The Judson blower for a VW 1200 engine of 30 cv is steered by two belts thanks to a special pulley which is mounted at the end of the crankshaft, thus always allowing the use of the dynamo belt. The body of the blower is directly mounted on the admission pipe while the original carburator is installed on the admission, on the left of the blower.

The carburettor is the original one, just equipped with bigger jets provided with the kit.

To ensure a perfect lubrication of the blades, oil coming from a glass tank is injected directly in the admission by a depression system. According to the engineers from Judson, this oil, that afterwards goes to the cylinders to be burnt with the mixture, increases the engine life as it ensures also the lubrication of the upper side of the cylinders.

The installation of such a kit is no problem and only takes a few hours as it not necessary to take apart completely the engine, or to even take it out of the car.

The only modifications to make are the re-adjusting of the carburettor rating, Judson providing new jets, and the installation of a stronger spring on the gas pump in order to increase the flow. By the way the gas consumption increases slightly (approximately 5 %), which remains quite reasonable considering the performances. The power increases from 30 cv to 50 cv at 4000 trs/mn. As the engine does not settle when above 3500 laps, the speed reaches 135 km/h. But the most spectacular improvement remains the accelerations since this small Ovale now passes from 0 to 100 in 15,5 seconds instead of 30,5 seconds ! As you can see, installing a Judson blower on a 1200 had, at the time, all the advantages, except for the fact you had to remember to fill up the oil tank at every 1000 km.

At 150 dollars the kit (at the time), the company Conshohocken in Pennsylvania had then given satisfaction to approximately 100 000 VW owners, from the early 50's until 1972. Where are they today ?

This technical information on Judson has been issued in Super VW magazine nr. 70. This feature can be ordered from the Shopping space.