Valve & Port Sizes

[Gav240z]

This is just a general question about our engines and possibly applies across the board.

I am wondering though why the intake valves and ports are so much smaller than the exhaust ones?

It seems to me that whatever goes in must come out so why does so much more air come out than in? Is this the case? I was just looking at some of the new uploaded pics and it's always puzzled me that to make power in an engine it's the quicker you get it in and out that makes most of the difference.

Can anyone explain this to me?:cheeky:

[59ghia]

Gavin,

Actually the intake is the larger of the two, from what I understand, the volume in is larger then the volume out, since some is lost in the combustion process. I read that or heard it somewhere....

Dave

[Dale B.]

Well, from whatI have heard. The intake valve is larger because the vacuum that draws the air in is weaker than the preasure pushing the exhaust out.Therefore the intake valve need to be larger so as not to impede the air flow going in.

-Dale-