Unity Motorsports Garage dives into the deep subject of Vacuum Advance for Distributors. We take a look back and discuss this history of Vacuum Advance and talk to the #1 authority on the subject.. David Vizard. He goes into detail why most get it wrong on the street… The Point is… If you have a Hot Rod and you drive it on the street… A Vacuum Advance is a must if you plan on getting ANY fuel mileage!
Thanks for Watching
Andy
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Wow….that was great can't wait for part Two.Thank you Andy .
Thanks Andy another informative video . Just to throw you a curve ball buddy , here in New Zealand apart from having some of the worst gas in the world and at $ 2.19 a litre 95 octane some of the most expensive ( 100 octane – $2.80 litre ) our 95 is about your 89 our 100 is 95 with octane boost . Our longest straightest road goes for acouple miles the rest is winding , hilly , short distance goat tracks with a few highways . What I have found after extensive economy testing , tuning the rest first then fine tuning the vac adv only improves the off idle response and marginal mpg improvement on a trip , the problem being as soon as you touch the gas it always momentarily rattles regardless how much timing I pull , rich or lean or how much I slow the mechanical or limit the total .
Now I set em up with as much timing as the engine wants at idle , what total it likes then slow the curve to suit the gas and driving style .
Stock 500 ci 76 Eldorado with my custom headers and exhaust , mr gasket ad vac adv , 17.2 mpg .
69 road runner hot 440 my headers exh , 4spd , 3.5 , 28 tyre – 17.3 mpg .
1988 chev c30 ambo 3 ton , 350 , ported vortecs , isky 270 , headers my exh 400 , 4.11 , 29 tyre 650 spreadbore dp – 18 town , 24 trip .
DV will like this one – 65 mk 3 zepher 302 w, 9.5 isky 270 , eddy perf holley 600 , headers my exhaust 5 speed celica , 3.0 9 inch 24 tyre , 31.5 mpg on a trip . 20 / 22 in town cruizing..
Slightly different circumstances .
Economy is very important especially here , all in know is a rattling engine is hard on ring lands and bearings and you have to save alot of gas to equal that bill . Cheers Andy lol exuse my rattling on mate and have a fantastic day .
I’d love to hear more about initial/base timing in part 2. Great stuff, man.
I got my hands on similar material and studied it like PLAYBOY in the late 70s. Was a geek about it and still am , even ran my truck on an emissions dyno and almost met 1995 air standards. And I recall vacuum dashpots with thermal ported vacuum switches and combination manifold / ported dashpots. Goofy stuff. Vacuum hoses everywhere and Hondas back then. SMH.
good info