Engine related formulas

Here are some pretty interesting formulas you gear heads might enjoy!

How to get Cubic Inch Displacement (CID)
CID = .7854 x Bore squared x stroke x number of cylinders
example: .7854 x 3.346" x 3.346" x 2.756" x 1 = 24.23 cid ( 400ex)

How to convert to Cubic Centimeters (CC's)
CC = .7854 x Bore (mm) x Bore (mm) x Stroke (mm) x 1 Then divide that answer by 1,000.

How to convert to Liters
Liters = .7854 x Bore (mm) x Bore (mm) x Stroke (mm) x 1 Then divide that by 1,000,000

Exhaust Header Tubing Diameter
How they figure out the way to make headers.
Tubing Diameter = The square root of CID (cubic inch displacement) x 1900 then divide by
Length of exhaust tubing x RPM (where it will be making most of its power).
Example: 351 x 1900 div. by 20' x 6,000...
Now take the sqare root of 666,900 div by 120,000 and you should get 2.36" as your answer!

How to figure out HP and Torque loss by driving in different elevations
HP Loss= Elevation x .03 x (vehicle rated HP) then take that answer and div. by 1,000.
Torque Loss= Elevation x .03 x (torque) then take the answer and div by 1,000.
Dont know your tourque use this...

How to find Torque
Torque= 5,252 x HP div. by RPM (your making most power at)

How to get Horse Power
HP = RPM x Torque div. by 5,252
ex: 6200 x 28 div by 5,252 = 33.05 HP

Compression Readings
To find the lowest reading you have to get the highest reading and multiply by 0.75.
ex: 195 psi x 0.75 = 146 psi being the lowest amount you can have throughout all the cylinders.

Jimmy

another way to find the displacement of a and engine is
radiuse of bore squared X stroke X Pi (3.14) X # of Cyl. / (DIvided by) 1000

Ex. (400ex)
stock bore=85mm Stroke=70mm

42.5 (1/2 of 85) ^2(squared) X 70 X 3.14 X 1= 397013.75/1000=397cc's

really cool post!