yaristurbo Posted March 8, 2013 Share Posted March 8, 2013 I'm running a 5e and wanted to work out the ratio can anyone help2.0mm head gasket Piston specs Quote Link to post Share on other sites
AdamB Posted March 8, 2013 Share Posted March 8, 2013 You need to measure the cylinder head combustion chamber as well mate. Use a syringe, 1ml = 1cc. Quote Link to post Share on other sites
yaristurbo Posted March 8, 2013 Author Share Posted March 8, 2013 Head of then cheers bud Quote Link to post Share on other sites
AdamB Posted March 8, 2013 Share Posted March 8, 2013 No probs mate. I think they are around 39cc but obviously will change if any skimming or headwork has been done. Quote Link to post Share on other sites
yaristurbo Posted March 8, 2013 Author Share Posted March 8, 2013 What's the calculation for it using 39cc Quote Link to post Share on other sites
AdamB Posted March 8, 2013 Share Posted March 8, 2013 (edited) The Formula is : CR = (CV + CCV) / CCVWhere CV - Cylinder Volume and CCV - Combustion Chamber Volume Cylinder Volume = 1517cc / 4= 379.25cc Combustion Chamber Volume = (pi * 74.5mm2 * 2.508mm) / 4000=10.93276 + 39cc=49.93276cc Plugging back into the formula gives : (379.25cc + 49.93276) / 49.93276ccCR = 8.595 : 1 It's the virtually flat top pistons giving it the high compression. Hope that helps mate Edited March 8, 2013 by AdamB Quote Link to post Share on other sites
yaristurbo Posted March 8, 2013 Author Share Posted March 8, 2013 (edited) Pretty high comp then Edited March 8, 2013 by yaristurbo Quote Link to post Share on other sites
AdamB Posted March 8, 2013 Share Posted March 8, 2013 Yes mate, I'm sure thats right, been a while since I done it. Even checked it on a few online calculator things and managed to get around that sort of CR.If it has had headwork the cc in the head will be greater than 39cc, making more volume decreasing the CR and the flat top pistons with no dish at all contribute. Quote Link to post Share on other sites
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