Cubic Inch Calculation

[05stroker]

Does anyone know the calculation used to figure cu. in . of a motor ? For example mine is a 4.6 .030 overbore with a 3.75 stroker crank what is the cu. in of this motor and how did you come up with the answer?

 

[Bingo]

http://www.ajdesigner.com/phpengine/engine_equations_cubic_inch_displacement_b.php

 

[majajh]

calculator

Just search "cubic inch calculator".

In days past anything less than a 327 was considered too small for any kind of power. Now I have a 281!

 

[05stroker]

Just search "cubic inch calculator".

In days past anything less than a 327 was considered too small for any kind of power. Now I have a 281!

LOL , All that came up was this thread!

 

[sbgt05]

CID=[#cyl]*0.7854*[bore^2]*[stroke]

=[8]*0.7854*[(3.551+0.030)^2]*[3.750]

= 302.1 cubic inches

 

[Hawgman]

LOL , All that came up was this thread!

I think he might have meant google or just the internet in general, not the forum.

 

[05stroker]

CID=[#cyl]*0.7854*[bore^2]*[stroke]

=[8]*0.7854*[(3.551+0.030)^2]*[3.750]

= 302.1 cubic inches

Thanks for the repley that explains it well .

 

[05stroker]

I think he might have meant google or just the internet in general, not the forum.

You mean there is other places on the internet than mustang forums ?

 

[ClassJ]

In days past anything less than a 327 was considered too small for any kind of power. Now I have a 281!

Yes and no....No doubt the new small displacement V8s are fast compared to their 60's counterparts.

But a 281 NA is still is a TOTALLY different driving experience mashing the throttle and banging gears in a big block 400+ ci beast. Not always faster in the quarter....but from a low rpm roll you can't beat 500+ ft lbs of stump pulling torque at a few thousand rpm or so.

 

[US-1]

Real simple terms:

Bore X Bore X Stroke X .7854 X 8 (for an 8 cylinder engine) = cubic inches.

 

[RRRoamer]

For the more geometrically minded:

Displacement of a cylinder: Pi * R^2 * H (Pi = 3.14159...., R = Radius, or Bore/2, H = height, or Stroke)

So: Displacement of an engine cylinder: Pi * (Bore/2)^2 * Stroke = Pi * Bore^2/4 * Stroke

Simplify: Pi/4 * Bore^2 * Stroke = 0.78539 * Bore^2 * Stroke

Finally, for a multicylinder engine: Displacement = 0.78539 * Bore^2 * Stroke * Number of Cylinders.

The only reason I bring up the whole equation is more people still remember pi from highschool. "0.78539" is a "special" number. So why even try to remember it? Just remember the equation for a cylinder and pi and you are good to go.