compressed volume

[burgo]

my brain seems to be on a go slow and i cant work out how to get the compressed volume when i know the compression ratio, bore and stroke. so anyone know the formula?

[Sirnixalot]

let me see if i remember this right

the swept volume of the cylinder/compressed volue = the compression ratio so you need to know 2 of the variables to get one

the swept volume is relativley easy, you just need to do the bore x stroke to get the volume and then use the compression ratio to see what the compressed volume is.

im no where near any of my reference material so i might be wrong but im 90% sure this is how you do it. correct me if im wrong :thumb:

[burgo]

ive had a little play and it seems my compressed volume is 50cc, however i now need to make a guesstimate on the thickness of the head gasket

[Ash]

sounds a bit clever, why do you want to know that?

Also reminded me that you wanted those pistons? or not now?

[Stuart]

hang on ill work out the calculation bungle....


right.... damn i hate thinking at this time of day lol.

To find the Clearance volume (compressed volume) its

Swept Volume of one cylinder / (Compression ratio -1)

eg say you have a swept of 297cc and a CR of 8.34 then its
297 / (8.34-1) = 297 / 7.34 = 40.5 (give or take a few rounding errors)

Ill add it to my compression ratio calculation in the sig link.

[burgo]

thanks stuart at least i know how to do it properly now altho i beleave i got there in the end and worked out i would need a 1.6mm de-comp plate lol

and yes nova pilot i would still like them

[Stuart]

as a rough guide a 1.6 8V head that seemed largely unskimmed was 38CC

[burgo]

and a 206 gti 180 head ?? lol

[Stuart]

10 litres

[burgo]

with an 11.0:1 compression ratio lol

[Stuart]

yep.... thems frenchies make cars with magic

[pul16v]

errrmm interesting so what do you need to know the compresed volume for i assume your trying to work something out but cant think what knowing the compressed volume would help with

phil

[burgo]

i needed to know the compressed volume so that i could then work out what size de-comp plate to get the compression ratio i require