tell me what you guys think is more important, a higher compression ratio or flow#'s given all other variables being the same i.e. runner volume. say, if i compared two sets of similar heads, one flows 220cfm @ 28" and .500 and has a 10.5:1 compression ratio; the other flows 250cfm @ same and has a 9.7:1 c/r. which is going to be faster?

 

i think the real question is which would make more power.. faster would involve way too many variables such as weight of the vehicle its in, trans and rear gearing, driver ability, elevation to name a few.. and thats a good question maybe someone will chime in

 

Id have to say flow. A while back car craft did an article about how much power cr was really worth and they only got like 1 or 2 percent from a one point increase. The higher flow should be able to make up that 1 or 2 percent at the upper end so id have to say flow is more important.

 

Without a doubt at all, the better flowing heads have much more power potential.

 

For hp sake flow is what you want. For efficiency you want high compression ratios. If we could run gasoline engines at the same CR's as diesels they would be more efficient than any diesel ever made. They are currently working on a type of anti-knock devise that will allow up to 15:1 on pump gas without detonation. Their goal is 20:1. There is a little team here made up of automotive pioneers and ME grad sutdents here at school that say they know how and have tested it sucesfully on no other than a small block. However, they will not devulge anymore than that.

 

dankhound do you know what issue that article was in?

 

Is that the article about someone stacking head gaskets to lower compression on the same motor?

 

i'd say flow=more power

 

It depends on the rest of the combo. You can't generalize like that in an information vacuum.

However, with other parts surrounding them that are appropriate to them, the better-flowing heads will probably outrun the others. If you use the same cam, intake, headers, gear, etc., it's anybody's guess, because those things can easily eclipse the difference in those head specs.

 

Yep the artilcle was stacking gaskets on a mopar i think. It was a few years ago but like all magizines they recylcle some of the general tech stuff so i wouldnt be surprised to see something like that again.