compression.....help

[jimmyfunk]

I've read some of the discussions on compression and even heard some of my friends speak on the matter. Can someone please give me a simple explanation on what the ratios mean to me? You won't insult my intelligence by keeping it elementary.

[madtownhonda]

Compression ratio is the total volume of the cylinder and combustion chamber when the piston is at BDC and when it's at TDC. BDC and TDC are Bottom Dead Center and Top Dead Center.

You can increase the compression ratio by adding pistons with higher domes, by adding a thinner headgasket, milling the head, etc. Every time you decrease the quench area, it will raise the compression ratio.

A lot of guys want to lower the compression ratio so their motor is more suited for forced induction. Some ways to decrease compression ratio, basically the opposite of what you would do to raise the compression ratio.

Any questions, just ask

[CivicEx95]

Think of a two liter pop bottle, if you were to compress the air in that so it takes up 1 liter, that would be 2:1 compression ratio. 200 ML would be 10:1 compression ratio. Same goes for a cylinder and the piston does the compressing. Understand?

[jimmyfunk]

awesome answers....that helps alot....i might have a few more questions about it but that's great for now

[ric]

the actual formula to find the compression ratio is

CR=((volume of cylinder+volume of combustion chamber) / volume of combustion chamber)