Ignition advance, was Re: alternative engines, WARPED

[EFISYSTEMS at aol.com]

Hi all,
     I could be wrong at this, but what I have seen is, ported vacuum is dead 
at idle, because it is above the butterfly....and as throttle is increased, 
vacuum is generated at the "port" and does not go away at full 
throttle,,,,,great for emissions but terrible for performance,,,,,the same 
for MPG....
-Carl Summers

In a message dated 99-05-19 02:14:13 EDT, you write:

<< >
 	
 
 	You sure about that?  I have always understood that a vac advance can
 reads ported vacuum in order to affect a curve that begins as the throttle
 is opened and increases as more throttle is applied, up to the point at
 which all vacuum (manifold and therefore ported as well) fades under heavy
 throttle openings, at which point the advance will decline again and the
 engine will see only mechanical advance.  This is apparently to provide
 extra advance for economy at part throttle.  Anybody who can further
 illustrate this concept, please do because if I am wrong here I'm going to
 have some serious rethinking to do!
 
 
 	Aaron Willis
 	ICQ #27386985 >>