Igneous Rock is formed when a magma cools underground and crystallizes or when it erupts unto the surface of the ground, cools and crystallizes. Magma that erupts onto the surface is called lava. When magma cools slowly underground the crystals are large enough to see.
Readings for compression tests usually vary between 175 to 250 PSI (Pounds per Square Inch). A higher reading generally indicates better engine performance; however you should check your vehicle manual to find out what the ideal reading should be for your vehicle.
The compression ratio is the ratio of the volume of the cylinder and the combustion chamber when the piston is at the bottom, and the volume of the combustion chamber when the piston is at the top. Automotive engineers can improve fuel efficiency and fuel economy by designing engines with high compression ratios.The higher the ratio, the more compressed the air in the cylinder is.When the air is compressed, you get a more powerful explosion from the air-fuel mixture, and more of the fuel gets used.he higher the ratio, the more compressed the air in the cylinder is. When the air is compressed, you get a more powerful explosion from the air-fuel mixture, and more of the fuel gets used.