Ported vs full vacuum advance
WebApr 6, 2008 · Ported is the proper way to run vacuum advance. If manifold was the correct way to go, why did not factory engines ever come that way? If the engine runs better with manifold vacuum, then you are just covering up a setup and tuning problem by running extra advance at idle and low speed. WebApr 12, 2012 · When emissions became mandated, vacuum systems went to ported. This reduced emissions (NOx I think), but if you run this way, you have to adjust your settings to prevent too much advance under load, because the ported vacuum provides advance with venturi velocity.
Ported vs full vacuum advance
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WebJul 9, 2007 · Discussion Starter · #1 · Jul 9, 2007. I have a 70 SS 402/350, th400, and a quadrajet carb and I cannot locate ported vacuum on the carb. I recently installed a new distributor and currently have my initial timing at 16 degrees with a total of 36 degrees with the vacuum advance unhooked from the distributor and plugged. http://chevellestuff.net/tech/articles/vacuum/port_or_manifold.htm
WebJan 30, 2004 · The advent of smog rules in the late '60's & early '70's brought the use of ported vacuum. Vacuum advance at idle makes a car idle smoother & with less throttle opening, but it also increases emissions. Later cars with distributors designed for ported vacuum should probably use it. WebMay 8, 2024 · Ported vacuum advance adds a second acceleration timing curve to the engine, to help make ultra lean combustion more complete, at the cost of efficiency, cooling and fuel economy.
WebFeb 11, 2012 · Premium Member. 1970 SS454 LS6 11 second street car. Joined May 8, 1999. 19,825 Posts. #5 · Feb 9, 2012. once the throttle plates open,it doesnt matter if its ported or vacuum at that point. Manifold vacuum does help at idle if you have a large cam. My 1970 SS454 LS6 SuperCar certified stock appearing 11.90@113 MPH. WebSep 10, 2002 · Optimum total advance is about 35 to 38 degrees. A vacuum canister can pull in as much as 60 degrees total advance. Fine for light cruise for gas milage but bad for a heavy load. This is when you start to put holes in pistons and break cranks. True, ported or timed, will improve idle is some cases, but adjusting the vacuum curve on the canister ...
WebJun 20, 2016 · Now, to the widely-misunderstood manifold-vs.-ported vacuum aberration. After 30-40 years of controlling vacuum advance with full manifold vacuum, along came emissions requirements, years before catalytic converter technology had been developed, and all manner of crude band-aid systems were developed to try and reduce hydrocarbons …
WebMar 30, 2024 · 1. Ported vacuum advance for emissions controlled engines. Carburetor Vacuum port above throttle valves. 2. Non-ported full vacuum advance for pre-emissions … darkesville wv civil war mapbishomoallylicWebMay 28, 2007 · Now, to the widely-misunderstood manifold-vs.-ported vacuum aberration. After 30-40 years of controlling vacuum advance with full manifold vacuum, along came emissions requirements, years before catalytic converter technology had been developed, and all manner of crude band-aid systems were developed to try and reduce hydrocarbons … dark ether trophy chest esoWebNov 23, 2011 · Nov 19, 2011. #2. EGR Valves - Ported vs. Manifold Vacuum. There are two sources of vacuum which is used to power many systems on our FSJs. Manifold vacuum, which is the present in the intake manifold, is the main source. It powers systems like the power brakes, heater controls, diverter/air management valve, etc. darke thing belowe memphisWebMar 21, 2012 · Ported distributor vacuum advance was a result of early 70's emission equipment. It comes off the venturi above the throttle plates and is effectively isolated by … dark ether movieWebNov 22, 2012 · The application of vacuum advance is left till after you dial in where your initial and mechanical needs to be. Using a limiter plate to prevent the vacuum advance from adding more than approx 12 deg of timing is the best trick you can implement when it comes to vacuum advance. darkets white home depot sells snp11marWebOct 8, 2011 · Vacuum advance There are actually 3 different vacuum advance modes. Ported venturi vacuum. Responds to engine rpm Used on some emission engines. Ported … bis homme