jlevasseur Posted December 22, 2009 Report Share Posted December 22, 2009 I know there are sites that I can got to and input the bore and stroke to figure out the cc displacement but I was wondering what the formula was so I could do it myself just to know. For example what is a 18 mil DM 78mm bore?? something like a 680 or so right? the formula would be sweet thanks. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted December 22, 2009 Report Share Posted December 22, 2009 Bore X Bore X Stroke X an engineering constant / number of cylinders. I can't find that constant for the life of me. But here's an easy to use calculator. Use millimeter as the unit of measurement. http://www.bgsoflex....splacement.html Wait, .0031416 is the number. So, I have a 68 bore cub with a 64 mm stroke (10 mil cub) 68X68X64X.0031416 /2 = 464.8 cc...or a 465 cub as they're called. Quote Link to comment Share on other sites More sharing options...
alcoholbanshee Posted December 22, 2009 Report Share Posted December 22, 2009 Bore X Bore X Stroke X an engineering constant / number of cylinders. I can't find that constant for the life of me. But here's an easy to use calculator. Use millimeter as the unit of measurement. http://www.bgsoflex....splacement.html Wait, .0031416 is the number. So, I have a 68 bore cub with a 64 mm stroke (10 mil cub) 68X68X64X.0031416 /2 = 464.8 cc...or a 465 cub as they're called. I use bore x bore x stroke x .0007854 x # of cylinders = displacement........................... all numbers in miilimeters........... Quote Link to comment Share on other sites More sharing options...
dajogejr Posted December 22, 2009 Report Share Posted December 22, 2009 Yes sir...that works too! If you multiply .0007854 by 4, you get the same number as an engineering constant (.0031416) 6 of one half dozen of the other! Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted December 22, 2009 Report Share Posted December 22, 2009 I use bore x bore x stroke x .0007854 x # of cylinders = displacement........................... all numbers in miilimeters........... I use this same formula Quote Link to comment Share on other sites More sharing options...
alcoholbanshee Posted December 22, 2009 Report Share Posted December 22, 2009 (edited) Yes sir...that works too! If you multiply .0007854 by 4, you get the same number as an engineering constant (.0031416) 6 of one half dozen of the other! Yeah I am not an engineer......I work for a living.................... Edited December 22, 2009 by alcoholbanshee Quote Link to comment Share on other sites More sharing options...
jlevasseur Posted December 23, 2009 Author Report Share Posted December 23, 2009 sweet guys.....thanks. Is there a easy way to figure out the constant without remembering it?? And how about figureing out the mm of a stroke? How would you figure out what a 18 mil stroke would be? thanks for all the help!! Quote Link to comment Share on other sites More sharing options...
dajogejr Posted December 23, 2009 Report Share Posted December 23, 2009 sweet guys.....thanks. Is there a easy way to figure out the constant without remembering it?? And how about figureing out the mm of a stroke? How would you figure out what a 18 mil stroke would be? thanks for all the help!! Nope...you remember the number or search for a displacement calculator online... A stock banshee stroke is 54mm (yeah, another number to remember ) So add the 18 to 54. Quote Link to comment Share on other sites More sharing options...
Confederate350 Posted December 23, 2009 Report Share Posted December 23, 2009 bore x bore x stroke x # of cylinders x .7862 = displacement Quote Link to comment Share on other sites More sharing options...
rubberneck Posted December 23, 2009 Report Share Posted December 23, 2009 That magic constant is simply pie. From geometry guys remember that class. 3.1417. The reason the constant is 0.0031417 is because your measurements are in mm and you want your displacement in cc Quote Link to comment Share on other sites More sharing options...
jlevasseur Posted December 23, 2009 Author Report Share Posted December 23, 2009 sweet guys thanks!!!!!!!!!!!!!!1 Quote Link to comment Share on other sites More sharing options...
slowblueshee2 Posted January 10, 2010 Report Share Posted January 10, 2010 1/2 the bore x 1/2 the bore x stroke x 3.14 x number of cylinders. But you have to move the decimal point for example a stock engine is 64bore x 54stroke. It would be 3.2 x 3.2 x 5.4 x 3.14 x 2 = 347.25888. Say a 10 mil dm. 78bore x 64stroke. It would be 3.9 x 3.9 x 6.4 x 3.14 x 2 = 611.32032 Quote Link to comment Share on other sites More sharing options...
alf44 Posted January 10, 2010 Report Share Posted January 10, 2010 This is the easiest i have found. Just punch in the numbers http://www.havocperformance.com/ENGINECALCULATOR.htm Quote Link to comment Share on other sites More sharing options...
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