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Re: vacuum advance vs. vacuum retard (archive)
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Posted by Dwight H. on September 25, 2000 at 17:34:46:

In Reply to: Re: vacuum advance vs. vacuum retard posted by darrell on September 25, 2000 at 13:48:00:


The thing is, modern ignition systems actually read throttle opening ( or vac ) and engine RPM to form 3 dimensional data maps of what happens to work best for that engine. The vac adv modules can only implement "advance should go down as vac goes up" or "advance should go up as vac goes up". Neither one is particularly useful at any given RPM. At some RPMs you want to increase advance when you open the throttle a certain amount, at other RPMs you will want to decrease advance.

From a stock point of view there were EGRs and thermal reactors, air pumps,... and the engineers had a particular reason to do what they did, but it bears little resemblance to what you want to do to get more power out of a modified engine.


Agreed. I was referring to a stock setup. The cetrifigual advance is supposed to take care of the engines advance requirements when the vacuum is not engaged.
Computerized systems are far superior but for the old stock engines, this is all we have to rely on unless massive $ are dumped into a computerized ignition system.


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