Affirmatron, Dave Lieb...
"Vacuum advance"
1. Ported to CARB.....
disconnected while setting dynamic timing
2.Ported to MANIFOLD.....(emissions)
stays connected while setting dynamic timing
What I've been told by my mechanic (IOW,
I don't "know"!:)
Each type creates a more complete burn
under part-throttle operation depending
upon induction system vacuum (depression).....
"1." was intended strictly as a "fuel economy" device. No BFD.
"2." was intended as much, if not more for
cleaning up emissions along with economy,
the signal from manifold "magnifying" such
signal for greater or tighter accuracy/control in "amount" and "rate" for the
sake of emissions (law).
I am open to further education by more
knowledgeable listers than I in these
respects. :)
BTW Dave, a fellow midgsprite lister has just installed "your" recommended JC
Whitney muffler. He is very pleased with
it's not overly loud sporty exhaust note! :)
Cap'n. Bob '60 :{)
|