Double check my engine builder please 340 stroke

CPMotorworks said

I would suggest you buy PIPEMAX, it gives correct numbers and is very useful.
OP, I come up with 11.88:1 Static, 10.834 DCR,

Click to expand...

Unfortunately, this program calculates DCR in a very different way, one that looks to be totally unrealistic and unusable. It computes the effective stroke as if the intake valve is completely closed at .050" lobe lift; that is OK for anyone thinks the valve is effectively sealed at a valve lift of .075". (If so, we won't ever have to worry about valve leaks again LOL.) This program also computes a 'DCR at valve lash' which is closer to the numbers that normally get discussed as DCR.

That is always a squishy aspect of DCR computations... at what angle is the intake valve effectively closed and the cylinder pressure starts to build. IMHO this Pipemax program gives an unusable DCR answer; it works the DCR at an intake closing of 43* ABDC. Others use 15 degrees after the .050" point on the intake lobe, or 58* in this case. And then the one I use takes it at the 'advertised' closing point, or 76* in this case.