Re: Freiburger, DCR, and testing.....
Early intake closing timing + medium static compression ratios = high cranking pressures. If you go bigger with the cam the cranking pressure will come down, if you go smaller it will go up. Of course going higher with the static compression ratio will increase the cranking pressure too. The calculator is just using math to quantify this.
A DCR calculator is just taking a known volume of air and calculating how much it will be compressed. It is using the swept volume, chamber volume, and intake valve closing point to determine the compression ratio. The fancier calculators are adjusting the "known volume of air" for density altitude and VE and converting the output to cranking pressure.
I have an actual DCR calculator formula somewhere and if I can find it I will post it, but it a big messy formula that is a pain to work through by hand.
Originally posted by Saltfever
A DCR calculator is just taking a known volume of air and calculating how much it will be compressed. It is using the swept volume, chamber volume, and intake valve closing point to determine the compression ratio. The fancier calculators are adjusting the "known volume of air" for density altitude and VE and converting the output to cranking pressure.
I have an actual DCR calculator formula somewhere and if I can find it I will post it, but it a big messy formula that is a pain to work through by hand.
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