Need help figuring out my dynamic compression.

nm9stheham said
Using the Pat Kelley calculator and estimating the intake closing angle at 71 degrees, it comes up with 11.6 and 8.8 for SCR and DCR. So these are the same numbers essentially.

The 10.03 DCR number posted comes from using the .050" intake closure angle rather than the at-seat intake closure angle. (Not the way to do it....)

FWIW, some calculators (like the KB one IIRC) back up from the seat closure angle by some number of degrees and run the DCR number there, which gives a lower DCR number. The Kelley and Wallace calculators are conservative in that regard (give higher DCR results).
Click to expand...

That's why I prefer the wallace calculator. Using seat to seat gives you a better number in my opinion. And yes lash and what not eats up some of that intake angle. But I'd rather guess a hair high on DCR than a hair low. For obvious reasons.