INCREASING COMPRESSION RATIO
Formula for CR
CR = COMPRESSION RATIO = CYL. VOLUME @ BDC ÷ CYLINDER VOLUME @ TDC= 1
+ (SWEPT VOLUME ÷ VOL @ TDC)
= 1+ (0.7854 x BORE x BORE x STROKE) ÷ (CCV + HGV + PDV)
CCV = Combustion Chamber Volume, in cubic inches
Note: if volume is given in cc’s then ÷ 16.4 to get cubic inches.
HGV = Head Gasket Volume, in cubic inches, = Head gasket
compressed thickness x 0.7854 x bore x bore
PDV = (Piston Deck Volume) + (Piston Dome Effective Volume)
= (0.7854 x bore x bore x deck to piston distance) + (volume of piston depressions
- volume of piston bumps)
Increasing the compression ratio of an engine can be done with the addition of better Heads and Pistons. Increasing the chamber size of the Heads can result in a higher compression. Also, increasing the standard bore size of the cylinders results in a larger combustion chamber, therefore, increasing the compression. Pistons also play a larger role in increasing the compression ratio. forged Pistons will also increase the compression of the chambers.
Aluminum Edelbrock Heads
IGNITION SYSTEMS
The ignition system is designed to transform the low voltage from the Battery to a higher voltage required to produce the spark that ignites the compressed mixture of air and fuel in the combustion chamber. The system includes the Ignition Coil, the Distributor, the Spark Plugs, and the high or low tension wires. By creating a high tension spark, increases an engines power by forsing the piston back down the cylinder.
