| Hemi Design Performance Products, Inc. |
In 1991 Hemi Design Performance Products developed a new Hemi engine. Fred Hall- Hemi Design founder and inventor of Hemi Design's patents, coined a phrase when the company first got off the ground, "If you haven't seen a Hemi engine lately, then you haven't seen a Hemi engine". By Definition, a Hemi engine is an internal combustion engine which has combustion chambers made into a hemispherical shape. Hemispherical shaped combustion chambers have been around since shortly after the internal combustion engine was created. Hemi engines have been in use since at least 1903 by car makers such as Pipe, Peugeot, Alpha Romeo and Jaguar. Hemi Engines became the most popular back in the late 60's and early 70's. The main disadvatage of using previous Hemi engines was the use of large combustion chambers which required the use of large domed pistons to increase compression to nominal levels. These pistons were heavy (high reciprocating mass) and the large dome shrouded the spark plugs and valves, requiring more ignition timing advance and increasing hydrocarbon emissions. What most people do not know is that all of these previous Hemi engines are not true Hemi's. Their Radii are not mathematically complete hemispheres. Hemi Design modified this type of engine and developed a patented piston and combustion chamber with a perfectly matching radius and specific chamber diameter and depth. We raised the deck of the piston to compensate for the head gasket so the radius of the piston starts on the same plane as the radius of the combustion chamber. This piston is a flat-top, which is essential for uninterrupted flame travel. The technical name of the piston is a "Truncated spherical flat-top piston" and the combustion chamber is a "Segmented hemisphere". This design of the radius piston gave the Hemi engine something it never had before; a quench area which creates turbulence, prevents detonation and results in a clean burning, efficient high horsepower producing engine. This combination has never been used in the automotive or motorcycle industry. It is the most advanced head and piston design ever engineered for a Hemi engine.
|
|
95% of Hemi Design's business is dedicated to Harley Davidson engines. In particular, the Evolution engine and the Twin Cam engine. The valve train on these engines are a perfect compliment for the Hemi Design combustion chamber and matched radius piston. We sell complete performance cylinder head kits and performance piston kits. All of our piston kits come with forged pistons; However, we do offer hypereutectic pistons from KB as an option.
|
Our H D Performance kits can be used for high compression engines used in racing applications, stock to mid compression ratios for touring and low compression applications for use with blowers & turbos. Any desired compression ratio can be supplied, from 7:1 to 17:1. Our Harley applications can be used on the Evo engine, all Big Twin and all Sportster models, and all Twin Cam engine models. We use heads such as Factory Harley castings, Screamin Eagle, S&S, STD, Jims, RevTech and Edelbrock. Our custom made kits include parts from Crane, Andrews, Mikuni, Vance & Hines and Screamin Eagle. We also deal with several piston manufacturers, such as: Ross, Arias, JE, Wiseco, KB and CP pistons.
|
Listed below, are our actual patents. Just click on the patent number, in the middle of the circle, to view them.
|
|
