So can someone explain it? Thanks.

Mac

 

Hemi Hemispherical
HEMI Hybrid EFIE (Electric Field Integral Equation) /MFIE (Magnetic Field Integral Equation) Iterative
hemi hemispherical (combustion chambers in engines)

This is what I found.......

 

http://en.wikipedia.org/wiki/Hemi
http://en.wikipedia.org/wiki/Chrysler_Hemi_engine
http://www.hemi.com/

 

Cubustion chamber shape is hemispherical as opposed to a more wedge shape chamber that is much more common. Intake valve is on intake side of head and exhaust is on exhaust side with spark plug between, wedge generally has boyh valves on intake side of head and plug comes in on exhaust side

 

actually just about all modern four valve per cylinder engines are hemispherical in shape this covers all of teh overhead cam engines. however mopar trademarked the term Hemi back in teh late 50's early 60's and so no one else can use that in their name.

 

a lot of people like to quote what they read but really don't know what they are talking about.. the combustion chamber in the head is shaped like a half of a ball with the spark plug in the center which is the optimum and most efficient way to completely burn the air/fuel mixture ang generate the best horsepower. another way is to create a vortex or swirl in the combustion chamber to efficiently burn the mixture.