Gasoline Engines

Gas engines are known as internal combustion engines and are divided into two general classes, specifically two cycle and four cycle engines. A cycle of an engine represents one stroke of the piston or one half revolution of the crank shaft, as a complete revolution represents two cycles. With a two cycle engine, the power impulse occurs at each revolution, while with four cycle engines it occurs at every other revolution, hence the terms two and four cycle engines.

Both classes have their own specific advantages and uses. For autombiles, the four cycle engines is most used. For motor boats on the other hand, the two cycle engine is most often used.

The horse power of gas engines is designated as HP and also brake test HP. The IHP is the theoretical HP, which is found by figuring different formulas, in which the diameter of the bore, length of the stroke in inches, and number of revolutions per minute form the basis for calculation. The results are found by the use of such formulas.

The BTHP on the other hand, is the power the engine actually develops in service, and is considerably less than the IHP. Keep in mind, this depends upon the degree of the mechanical perfection attained in the construction of the same. If both the compression and construction are good, the engine may actually reach 80 - 88% of the intended IHP.

With gasoline engines, high HP and high RPM ranges are what makes them popular. Gas engines have always been more popular than diesel vehicles, for the simple fact that they can achieve more speed. If speed is what you are after, gasoline vehicles are what you should be looking for. Although they may lack in torque and raw power, they make up for it with speed and tuning options.