Hemi Performance

If you are a type of person that likes cars, then most likely than not you have heard of the Hemi engine. Even if you don't know that much about cars, the Hemi engine still might raise some interest to you. The word Hemi has been associated with big, powerful engines. And that right there is what fast cars are all about.

The Hemi engine is an engine that has a hemispherical-combustion chamber design and is an internal-combustion engine. On the top of the combustion chamber is developed in hemispherical form. The head of the combustion area is shaped like a half of a sphere, which this type of engine is said to have hemispherical heads. Located at the top of the combustion chamber in the Hemi head, is the spark plug. The valves in the Hemi head will open on the opposite sides of the combustion chamber.

Some of the cars you see have an in-line valve arrangement, which is common with engines with the wedge-shaped combustion chambers. Most cars before the 1950's had engines known as flat-head engine. Because this design is less expensive to manufactures, many lawnmowers use this engine design. With the flat-head design, the valves are in the block and open in the chamber beside the piston.

An advantage that the Hemi engine has is the surface area is smaller than of a flat-head engine. Flat head engines have a larger surface area than a Hemi engine, and this causes heat loss. The fuel does not burn as efficiently because it is near the head walls, so it cools more. Since a Hemi engines surface is smaller, the less heat escapes and the higher the peak pressure is. Also, a Hemi engine head has more room for valves and the bigger the valves, the more improvement in airflow through the engine for a higher performance.

There are also some disadvantages for the Hemi engine. The desire to create a combustion chamber that is smaller is why most high-performance engines don't use a Hemi design for the engine. This is because the small chambers reduce the heat that is lost during combustion, and shortens the distance the front flame that has to travel during combustion.