hondacivic4g

If i'm using a D15B block , a D16Y7 head and D16Y8 head gasket, how do i determine my cubic displacement?
Thanks-Jason

1700anddroping

borexstroke, head gasket or head has nothing to do with it.but if you were talking about compression,the you could put ^^^^^^^^^^^^^^^^^^ into the equasion.

L-B racing

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1700anddroping &raquo;</TD></TR><TR><TD CLASS="quote">borexstroke, head gasket or head has nothing to do with it.but if you were talking about compression,the you could put ^^^^^^^^^^^^^^^^^^ into the equasion. </TD></TR></TABLE>

the head actually does matter. its all space inside the cylinder so it is displacement. if you have a head with a 30cc chamber and a head with a 40cc chamber thats an extra 40cc's you have to add to what you block is.

hondaZvic

equasion?

gomer124

well, you need to fill up a cylinder with water, and then multiply it by 4
lol

Lsos

Head makes no difference. You could slap on a 50 liter head and your displacement wouldn't change. You could take the head off and then argue that the head volume is the infinite size of the universe...but your displacement wouldn't change.

EGbeater

This will help a lot. You can see that the head chamber volume does matter in calculating displacement, but very very little. It does make a big difference in terms of C/R though.

http://www.knology.net/~jediklc/D.htm

L-B racing

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Lsos &raquo;</TD></TR><TR><TD CLASS="quote">Head makes no difference. You could slap on a 50 liter head and your displacement wouldn't change. You could take the head off and then argue that the head volume is the infinite size of the universe...but your displacement wouldn't change.</TD></TR></TABLE>

look you can believe what ever you want thats fine with me. if you really want to get technical you also need to take the piston into the equation.

heres a simple example i hope you can follow. for my example ill use a 85x89 ls block. a online displacement calc says its 2020cc's. well say thats with a flat dome piston. now if you leave the motor the same size and add a 8cc dome piston you are now taking up an extra 32cc's. does the displacement change?

now you have a gsr head that has a 42cc chamber and a b16 with a 45cc chamber. theres gonna be a difference there too.

it may not be much but it actually matters if you really want to find out your true displacement. if you motor was to get pumped for a displacement check, they stick a air fitting in you spark plug tube and have a guage that reads how manyy cc's or ci's of air is put into the cylinder. dou you think that air isnt going to fill in the head chamber becuase "it dosnt matter"?

i hope this explains any questions anyone might have on this subject.

L-B racing

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRXMR2SM2 &raquo;</TD></TR><TR><TD CLASS="quote">This will help a lot. You can see that the head chamber volume does matter in calculating displacement, but very very little. It does make a big difference in terms of C/R though.

http://www.knology.net/~jediklc/D.htm</TD></TR></TABLE>

thats a good link. have one for b-series?

Lsos

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">does the displacement change?</TD></TR></TABLE>

No.

By definition displacement is the volume that the piston sweeps.

pi*(.5*Bore)^2*stroke.

Head volume and piston size do not affect the volume that the piston sweeps. Not a lot, not a little. Nothing. You do not take them into the equation. They are not part of it. If they are, you are not calculating displacement. Total combustion chamber volume does not affect the swept volume.

If an online calculator tells you otherwise, it is wrong or they made up their own definition and should not be trusted. This is not just my belief, it is a definition that has been established by the industry for years.

http://www.smokemup.com/auto_math/displacement.php
http://www.jobriteauto.com/cal...t.htm
http://www.web-cars.com/math/displacement.html
http://www.hyattracing.com/rac....html
http://bugsandbuggies.com/Eng_Disp.asp
http://bugsandbuggies.com/Formulas.asp

https://honda-tech.com/zerothread?id=591084
https://honda-tech.com/zerothread?id=520453
https://honda-tech.com/zerothread?id=292385
https://honda-tech.com/zerothread?id=239510

Lets say a dude is in a house and he can jump up 1 ft high. He has a 1ft jump. Now raise the ceiling by an inch. The dude will still jump 1ft. He still has a 1ft jump. Now put him in St. Peter's Cathedral. He will still have a 1ft jump. It will not go up to 1.02ft or 1.097ft. It will still be a 1ft jump. It's the same thing with displacement. The size of the combustion chamber is irrelevant.


Modified by Lsos at 4:56 PM 11/21/2003

L-B racing

theres 2 types of car enthusists in this world
the book worm.
and the people that can just figure it out.

personally i dont give a f*ck what a dictionary says what displacement is. the only thing that i care about is what that pumper reads. thats what my "definiton" is.

Lsos

Sorry dude

I'm an engineer by trade and I guess ideally I should be able to explain how things work through physics and formulas. If you can understand it from both a fundamental engineering principles perspective, as well as actually being able to visualize it, is when you get the best results.

There do exist people that can figure it out, but are bookworms as well.

For what it's worth, the pumper will read identically if the only thing you changed is the size of the combustion chamber.