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A direct comparison of the effects [illegible] systems on fuel and and engine behavior has been made using the same V-8 engine far both systems. Fuel was metered by a standard four-barrel carburetor in one case, and by a timed manifold-port injection system in the other case. With both systems, provisions were made for varying fuel-air ratio. A major portion of the work was done on an engine dynamometer, with sufficient vehicle testing using the same engine and fuel metering systems to verify the laboratory results. When only the method of metering fuel was changed, the following results were obtained: 1. Brake horsepower increased slightly when fuel injection was used; the increase varied from zero to a little less than 3 % depending on engine speed. 2. Fuel economy, as measured by brake specific fuel consumption, was the same with both systems throughout the manifold vacuum load and speed range of the engine when each system was operated to provide minimum specific consumption. 3.

The development of a successful fuel additive requires considerable effort, a large share of which must be expended on the effect of the additive on engine durability. Durability may be affected as soon as the fuel enters the fuel tank and the possibility of such good or bad effects continues until the exhaust gases have cleared the rear bumper. Some of the durability aspects which can be either improved or made more severe are listed, these include fuel system corrosion, carburetor and manifold deposits, combustion chamber and spark plug deposits, engine wear and general cleanliness and bearing, exhaust system and rear bumper corrosion. It is shown that of seven experimental additives tested in a fleet of passenger cars of one make operated under severe duty conditions, four additives decreased exhaust valve life while three increased exhaust valve life by from twenty-five to fifty per cent.