I'm working on a new project (what else do we do here really???) and I want to use a little bit of math and science in this instead of hillbilly ingenuity. I have a few fixed variables.
my question is, where do I start? Is it from the throttle plate? is it from the base of the throttle body or is it at the tip of the air horns where the air enters the throttle body assembly?
from the throttle plate to the runner s would be plenum volume. Runner length would be air horns to base of manifold. Wait would you include the runner length in the head?
And, as always, it depends....
If you are looking at improving volumetric efficiency at full throttle you would use the tip of the air horn to the intake valve (or the entry of the port for a rotary) because the throttle plate would be fully open and therefore mainly out of the way of any reflected pressure waves. If you are looking at part-throttle efficiency, you would use throttle plate to intake valve (port).
Evaluating a rotary presents some interesting questions about actual instantaneous pressures in the intake manifold due to the lack of a valve and the changing volume of the combustion chamber (intake chamber?) as the rotor turns. The desired result is usually using pressure waves to get more air into the engine at a particular rpm. But I am not sure what that would look like for a rotary.
Following along to see where this goes.
Opti said:from the throttle plate to the runner s would be plenum volume. Runner length would be air horns to base of manifold. Wait would you include the runner length in the head?
No I won't be measuring the runner length in the head. I was thinking from block to XYZ location? so I need to go from the throttle plate to the block; that would be my effective runner length.
You'll need to log in to post.
