Re: Vacuum Advance and why to use it on the street
Tommy, I hear what you are saying and I've heard it said before. My expereince is that the problem typically isn't a VA problem, but a tune that is less than ideal and done without consideration for the VA benefits. I would not expect your "perfect" tune to run better simpy by "hooking-u" the VA. As you can tell, I really beleive it in as being a crutial component to engine managment and long term engine health.
Just so I can qualify some of these conditions that it doesn't seem to work well on, can anyone validate the following items?
Engine type:
Cam lift and duration @0.050
Number of degrees the VA canister is pulling (should use a dial back timing light to verify, but I undestand if you are only using the stamped # to id the amount of VA)
Vacuum source:- manifold or ported
Initial timing
Mech advance timing
Total advance @ 3000 RPM
There is no argument here that every engine and combo is different. There can still be a common approach to dial in the best street friendly tune with todays pump gas.
The VA tune we are recommending really helps in off throttle conditions. You may be surprised at how similar the different engines with "hot" cams can act in off throttle conditions.
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Paul III
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