Figuring out the Displacement.

[zuLi0]

How is the Displacement (cc) of a motor actually figured out, Ive been told bore x stroke, but that always give me a funky number.

[Red Rooster]

Half of the diameter x half the diameter x 3.14 X the stroke.

My 300 has a (stock) stroke length of 65.5 mm and a (stock) bore size or74 mm sooooo....

74 divided by 2 (=37), times 37, times 3.14 (=4298.66), times 65.5 (=281,562.23 mm cubed) Wich would be 281.56223 cm cubed. You have to divide by 10, 3 times, to get the cm cubed.

Hows that for todays math lesson

[zuLi0]

It was great, but I took it one step farther. :) Check out the next post.

[zuLi0]

400ex Stock Bore Calculations

Bore 85
Stroke 70
----------------------------
-----Bore ÷ 2

85 ÷ 2 = 42.5
----------------------------
(Bore ÷ 2) X (Bore ÷ 2) -or- (Bore ÷ 2)²

42.5 X 42.5 = 1806.25
----------------------------
-----(Bore ÷ 2)² X 3.14 -or- (Bore ÷ 2) X (Bore ÷ 2) X PI

1806.25 X 3.14 = 5671.625
----------------------------
-----That X Stroke

5671.625 x 70 = 397013.75mm³
----------------------------
-----Divide 397013.75 by 10, 3 times -or- Move the decimal place to the left 3 times

397013.75 ÷ 10 = 39701.375
39701.375 ÷ 10 = 3970.1375
3970.1375 ÷ 10 = 397.1375

400ex = 397cc's

----------------------------
Further more to make it down to the nitty gritty then...


Bore divide by 2
Sqaure (Bore ÷ 2)
Take (Bore ÷ 2)² and Multiply by 3.14 (PI)
Multiply by Stroke
Divide by 10 3 times or simply move decimal to the left 3 decimal places.

Now that is how you find out your quad placement Ladies & Gentalmen!

I just didnt know the formula.

Formula by: Red Rooster300
Math & Documentation by: zuLi0
http://www.exriders.com

And also it is downloadable if you would like a Copy for yourself.

[ChadEXer]

Somebody posted a displacement calculator on here on another post. you just type in your bore and stroke and it gave you the cc's!!!!

[zuLi0]

Where?

Also its interesting to know how to figure it out by hand.

:huh

[400exRacerX]

They got one at bluetraxx.com,

http://www.bluetraxx.com/engine_displacement.htm

Originally posted by 400exRacerX
They got one at bluetraxx.com,

http://www.bluetraxx.com/engine_displacement.htm

The truth comes out,,Norms a traiter that rides a hopped up blasturd...LOL :D

[Red Rooster]

You got it good and deep, there, zuLiO. good work.

[400exRacerX]

Originally posted by Rico


The truth comes out,,Norms a traiter that rides a hopped up blasturd...LOL :D


:eek: How'd yah find out???:eek:

hey, I just figured out the displacement in Cubic inches for the 400ex: 24.227263ci to be exact. Funny thing is that I can beat my friend who has a chev350 with K&N filter and flowmaster pipes+headers in a drag race. And I stay in front of him for awile before he passes me. It is however 4wd, has 410 gearing(I know the raito isn't 410, something like 1:4.10? I don't know) and it's a 2500hd with a 3 speed transmition. I bet the newer vortec 350's would be close to the 400ex in a drag rece. power to weight makes quite a difference. other factors would probably include chain vs shaft, 1 small quick reving piston vs 8 big slower reving pistons. 24 vs 350. who would ever guess a 24ci would take a big 350.

[zuLi0]

Originally posted by Red Rooster300
You got it good and deep, there, zuLiO. good work.

Thanks. Just trying to make it so other people can maybe understand a little more.

Math was always my strong point, just didnt know the formula. :)

[zuLi0]

Here, Even made it up in vb, However this is for single cylinders only right now, will post any updates to better versions if anybody wants it.