Manifold Vacuum Advance what am I not getting?
Guys I guess I haven’t explained myself well. I believe I need manifold vacuum advance because it gives me full vacuum at idle and Cruz. This will allow me additional timing that my motor wants at idle 42° AND NOT RUN 54° at full advance! Ported will not do that.
See my hand drawing below.
This is what I’m trying to accomplish and I believe manifold vacuum is the only way to do it. I found top dead center three times stabbing the distributor three times blindly searching for idle quality and vacuum three times each time I get 42°. With 24° base timing I get 10Hg. At 42° space timing I get 15.Hg. My ears and eyes are telling the same story. This motor wants more advanced idle however at 42° initial base and with the curve I have in advance stop bushings. This IS MY ADVANCE curve below. This curve was selected to give me a slow advance because of detonation. My average cylinder pressures are running about 200 psi. This is a big problem. This is what I’m trying to deal with. Please see graphs and charts below.
I do realize that the vacuum signal will not be as quick as I would like to prevent detonation entirely or completely. But right now it’s all I got to work with unless you guys can think of something else.
Guys I guess I haven’t explained myself well. I believe I need manifold vacuum advance because it gives me full vacuum at idle and Cruz. This will allow me additional timing that my motor wants at idle 42° AND NOT RUN 54° at full advance! Ported will not do that.
See my hand drawing below.
This is what I’m trying to accomplish and I believe manifold vacuum is the only way to do it. I found top dead center three times stabbing the distributor three times blindly searching for idle quality and vacuum three times each time I get 42°. With 24° base timing I get 10Hg. At 42° space timing I get 15.Hg. My ears and eyes are telling the same story. This motor wants more advanced idle however at 42° initial base and with the curve I have in advance stop bushings. This IS MY ADVANCE curve below. This curve was selected to give me a slow advance because of detonation. My average cylinder pressures are running about 200 psi. This is a big problem. This is what I’m trying to deal with. Please see graphs and charts below.
I do realize that the vacuum signal will not be as quick as I would like to prevent detonation entirely or completely. But right now it’s all I got to work with unless you guys can think of something else.