(C.I.D) Cubic Inch Displacementisplacement:
The swept volume of all the pistons in the cylinders in an engine expressed in cubic inches. The cylinder displacement is calculated with this formula: (Bore x Bore x Pi x Stroke x No.Cyl.)/4. When the bore and stroke are measured in inches, the engine displacement calculated in cubic inches.
Bore:
The internal surface of a cylindrical volume used to retain and seal a moving piston and ring assembly. "Bore" is commonly used to refer to the cylinder bore diameter, unusually measured in inches or millimeters. Bore surfaces are machined or ground precisely to afford an optimum ring seal and minimum friction with the moving piston and rings.
Stroke:
The maximum distance the piston travels from the top of the cylinder (at TDC) to the bottom of the cylinder (at BDC), measured in inches or millimeters. The stroke is determined by the design of the crankshaft (the length of the stroke arm).
Compression Ratio:
The ratio of the total volume enclosed in a cylinder when the piston is located at BDC compared to the volume enclosed when the piston is at TDC (volume at TDC is called the combustion space volume). The formula to calculate compression ratio is: (Swept Cylinder Volume + Combustion Space Volume)/Combustion Space Volume = Compression Ratio.
Intake Manifold Type:
The intake manifold can be of many designs such as dual plane, single plane, tunnel ram, etc.
Cylinder Head Porting:
The process of modifying the intake and exhaust ports to improve the engine’s air/fuel flow. This provides the finely detailed attention needed to bring the engine to the optimal level of efficiency and power output. When a modification is decided upon after careful flow testing, the original port wall can be carefully reshaped by hand with die grinders or with advanced CNC milling machines. For more serious modifications, ports must be welded up or similarly built up to add material where none existed.
RPM Range:
Revolutions Per Minute. A unit of measure for angular speed. As applied to the IC engine, rpm indicates the instantaneous rotational speed of the crankshaft described as the number of crank revolutions that would occur every minute if that instantaneous speed was held constant throughout the measurement period. Typical idle speeds are 300 to 800rpm, while peak engine speeds can reach as high as 10,000rpm or higher in some racing engines.