How do you calculate cubic inches?
Melting Slicks
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From: Newland US
Re: How do you calculate cubic inches? (Gary2KC5)
Gary2KC5,
Multiply the (Area of the bore) by the (Stroke) by (Number of cylinders).
Area of the bore= pi time radius of the bore, squared.
Mark
Multiply the (Area of the bore) by the (Stroke) by (Number of cylinders).
Area of the bore= pi time radius of the bore, squared.
Mark
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Re: How do you calculate cubic inches? (Gary2KC5)
bore squared,3.911 X 3.911 X .7854 X 3.622 X 8 # of clys = 348.100 ci this is the method that all racing assoc. use. :chevy
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Re: How do you calculate cubic inches? (clem zahrobsky)
Clem,
thanks so much for your written out calculation. It helps to be able to take a calculator through it and understand it.
I still have a question though; what is the .7854? What is that multiplier?
Mark,
Thanks for you written out formula, I've written it down so I will remember it now.
Seamoore,
I've run through your math and can't replicate the 347.9219503. I get 348.1451 which is much closer to the calculation Clem and NASCAR comes up with.
I know I'm splitting hairs but in the interst of my gaining knowledge...inquiring minds want to know. numbers into a mathmatical formula should be exact.
I understand Clem's & NASCAR's formula is a little different but Mark's & your formula is, well "the" formula and I don't get the same answer.
please help me understand and come up to the chalk board and show your work.
BTW: a measly 2.3 extra inches, dang i was hop'n for twice that.
[Modified by Gary2KC5, 10:44 PM 9/3/2002]
thanks so much for your written out calculation. It helps to be able to take a calculator through it and understand it.
I still have a question though; what is the .7854? What is that multiplier?
Mark,
Thanks for you written out formula, I've written it down so I will remember it now.
Seamoore,
I've run through your math and can't replicate the 347.9219503. I get 348.1451 which is much closer to the calculation Clem and NASCAR comes up with.
I know I'm splitting hairs but in the interst of my gaining knowledge...inquiring minds want to know. numbers into a mathmatical formula should be exact.
I understand Clem's & NASCAR's formula is a little different but Mark's & your formula is, well "the" formula and I don't get the same answer.
please help me understand and come up to the chalk board and show your work.
BTW: a measly 2.3 extra inches, dang i was hop'n for twice that.
[Modified by Gary2KC5, 10:44 PM 9/3/2002]
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Re: How do you calculate cubic inches? (Gary2KC5)
I find the easiest way to figure cid is to take the diameterXdiameterX.7854Xstroke=cid in one cylinder, then X 8=
Stock C5 is 3.9X3.9X3.62X.7854X8=345.95c.i.d.
This formula can be used for cubic centimeters the same way. i.e.
75mmX75mmX.0007854X58.4X6=1548.02cc divide by 16.387 to convert to c.i.d. or 94.47 cubic inches. This is the displacement of my CBX Turbo.
Jim Hall
Stock C5 is 3.9X3.9X3.62X.7854X8=345.95c.i.d.
This formula can be used for cubic centimeters the same way. i.e.
75mmX75mmX.0007854X58.4X6=1548.02cc divide by 16.387 to convert to c.i.d. or 94.47 cubic inches. This is the displacement of my CBX Turbo.
Jim Hall
Melting Slicks
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From: Newland US
Re: How do you calculate cubic inches? (Gary2KC5)
Gary2KC5,
I ran the calculation to 3 significant digits and got 348.100.
All the formulas are equivalent. In Clem's formula, he is using (Diameter squared)/4 which is equivalent to (radius squared) in mine. The 4 was divided into the value of pi.....just simplifying the constants....pi/4 is where the .7854 came from.....3.1416/4=.7854.
So, nope, ya don't have a 350 cid, yet; guess we'll have to stroke her. :D :D
Good luck.
Mark
I ran the calculation to 3 significant digits and got 348.100.
All the formulas are equivalent. In Clem's formula, he is using (Diameter squared)/4 which is equivalent to (radius squared) in mine. The 4 was divided into the value of pi.....just simplifying the constants....pi/4 is where the .7854 came from.....3.1416/4=.7854.
So, nope, ya don't have a 350 cid, yet; guess we'll have to stroke her. :D :D
Good luck.
Mark
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Re: How do you calculate cubic inches? (Gary2KC5)
Gary2KC5
My bad. My non-typist fingers must have hit a wrong key on the caculator.
I've refigurred it 3 times and keep getting the same answer as the others. To be exact i get 348.0999382. It's not 350 but close enough if you want to say it is.
Seamoore
My bad. My non-typist fingers must have hit a wrong key on the caculator.
I've refigurred it 3 times and keep getting the same answer as the others. To be exact i get 348.0999382. It's not 350 but close enough if you want to say it is.
Seamoore
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Re: How do you calculate cubic inches? (SEAMOORE)
Seamoore,
I kept making mistakes on my calculator also, so I went to my Excel spreadsheet (also so I wouldn't keep having to enter the #'s over)
Anyway, thanks for your help. I guess 348 is a little closer than the stock 346.
Now on to converting these #'s to metric.
it's a true 5.70 vs. stock 5.66
[Modified by Gary2KC5, 12:58 PM 9/4/2002]
I kept making mistakes on my calculator also, so I went to my Excel spreadsheet (also so I wouldn't keep having to enter the #'s over)
Anyway, thanks for your help. I guess 348 is a little closer than the stock 346.
Now on to converting these #'s to metric.
it's a true 5.70 vs. stock 5.66
[Modified by Gary2KC5, 12:58 PM 9/4/2002]
