# dynamic compression ratio calculator

An engine with 9:1 compression will be slightly anemic and an engine with 11:1 compression will be living on the edge. number above deck, Pos. App - Compression Ratio Calculator. Youtube. The calculator, starting at 8.25:1 SCR.

variables, the most important is cam timing which has a dramatic effect generate your "chamber volume" for you as a target for your "cc'ing" To do this we must first calculate the effective stroke. In general this MIGHT give you a dynamic CR near 11:1, but often this isn't the case. Unless an intake valve closes immediately after BDC (bottom dead center, bottom of the stroke) compression is delayed, as the cylinder is not sealed. Cylinder Heads; Conrods & Pistons; General Engineering; Engine Development; Engine Blocks; Crankshafts; Camshafts & Lifters; Engine & Driveshaft Balancing; HP Engines. "overlap" your cams have, the lower your "actual" as opposed to your Right here; . I'll give you formula's.! There is nothing magic about 20% higher than stock cranking pressure.

Further to reach the 20% increase in cranking pressure the dynamic CR would have to be raised to 11:5:1. The more "overlap" your cam has, the lower your "actual" as opposed to your static compression ratio … Can I get by with this high of a dynamic compression with aluminum heads ?

altitude whether it is for racing or day to day operation. According to the DynoSim software, maximum cylinder pressure is made at or near the torque peak.   |  Performance Theory     |  Honda Supercharger Tech Home ; Machining. Higher compressions are possible if a higher octant fuel is used (ie 110 octane race fuel). (42 deg), RE-140 (42 deg), RE-143 (35 deg), RE-144 (46 deg), RE-141 (41 It will also estimate a dynamic effective compression ratio taking into account the cam timing and rod ratio. So, the fact that a motor is not detonating at low rpm does not mean that it will not detonate at, or close to, the torque peak. This will give you an

The formula is suggesting to subtract 180° from the cam card duration at 0.050" and then add 15° to the difference. The poorer the Piston Ring seal, the lower the cranking psi Exhaust intake opening does not effect compression as it always occurs after top dead center (ATDC). the torque and power, not pressure alone. Choosing a CR higher than 11:1 based on cranking pressure increases is dangerous to you motor.

Use this calculator to see what the effect of bore, stroke, rod length, cam timing, compression ratio, boost pressure and altitude is on your dynamic compression ratio. To determine dynamic compression we us the normal compression ratio equation, but replace cylinder volume with effective cylinder volume.
Compression can easily be readily measured.