If i have a motor set up at say 10:1 compression ratio, and i put in a cam with a high lift and duration will this change the compression??? My friend was telling me that it would, but i don't see how because it's not putting the head any closer to the block??? help please

 

changes dynamic compression. its all about the overlap i believe

 

cams dont change compression. compressions is changed when the distance from a piston at tdc from the combustion chamber is changed

 

yeh it changes dynamic compression like the guy above said..which is good..if you run high compression and a bigger cam you can usualy run a lil lower octane with out pinging cause of the overlap...

 

ok, i'm a little slow so could someone please explain overlap and dynamic compression???

 

http://www.rbracing-rsr.com/comprAdvHD.htm

 

hmm basicaly a big cam keeps the valves open a lil longer and kinda bleeds compression..thats the easiest way i can think of explainin it

 

You should try to stay with the compression ratio given by the cams manufacturer. Any company that wont give you at least a ballpark reccomendation I would stay away from.

 

ok thanks guys