> my PI has vacuum
> advance taken from the idle bypass port, way away from the butterfly, is
> that why they deleted it on later cars with the explanation that it had
> little effect on performance or economy.
I really don't know, but I do know we heard similar stories when vacuum
advance was deleted from US-spec engines. Is 5-10% "little effect" ? I
supposed it depends a lot on who is paying for the petrol !
> Another question on the advance port, I am guessing that the location is
> pretty critical, I would need to put this in real carefully,
Yeah, needs to be positioned fairly close, so it's just on the intake side
of the butterfly with the butterfly in idle position.
One alternative that I've heard of (never tried) is to use manifold vacuum
and cut it off at idle with a solenoid and throttle-activated switch.
Friend of mine reported about a 10% improvement in mileage on his
Weber-equipped TR4. 12v air solenoids were used on many cars so should be
readily available at a breaker. Might even be able to use the anti-runon
solenoid from a TRiumph, although I'm not sure how long they would last
under continuous activation.
Randall
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