another cam question for 98" build
Tourer
Joined: Sep 2014
Posts: 420
Likes: 5
From: Kingsport, TN
Using the Big Boys calculator, with 3.935" bore, 4" stroke, .030" headgasket, 83cc combustion chamber (don't know), .003"deck height (don't know), and 13cc piston dome volume (don't know), static cr is 11.42:1. Calculated Corrected compression would be 10.24:1 with the reaper 574 (45 degree intake close) & 217 psi CCP @ 141 ft elevation (Boston). With the reaper 594 (56 degree intake close), calculated corrected compression would be 9.60:1 & 200 psi CCP. Even if the combustion volume is a little higher and/or a little less dome height, looks like the 594 would've a safer choice compression-wise.
Last edited by dynawg1; Mar 15, 2015 at 01:24 PM.
HDF Community Team
Joined: Jun 2006
Posts: 12,776
Likes: 2,607
From: san antonio
Everyone seems to forget that static compression is just a number; doesn't mean anything as the motor never sees static compression. What the motor sees is corrected compression and CCP under operation. I ride in south Texas and high corrected CR/CCPs, don't care what octane fuel one is running, don't play well with south Texas summer heat.
It's the OP's ride and he can decide but the smart move would be to get the data, do the math and choose a cam that will put corrected CR in the 9.3-9.4 range and/or CCP between 185-190psi instead of flying blind. As usual JMHO.
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