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


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.

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