vacuumizing fuel for better economy

[Frank Lee]

I like vago's swept-winged cat head but imagine how awesome he'd be with a ram implosion wing?!?

[t vago]

Or I could get one of these...

[Jim-Bob]

Go ahead and put that ball valve in your fuel system. It will not do anything to change the actual NEEDS of the engine. Thus you will lean it out excessively and burn some valves or put a hole in a piston or 6. I also want to know how the bloody hell you could even get a quart of fuel into your vacuum lines? It's not like there is that much volume in even the most vacuum line choked V8 from the 70's, let alone a modern engine. Plus, most of the vacuum related components of the emissions controls and power brakes are not designed to be in close contact with gasoline. You will likely damage your power brake booster and dump all that fuel into the floor of the driver's side of the car where the next spark inside of a relay or old switch will be ready to ignite the mixture.

[mwebb]

no matter what
the ECM is going to use input from the 02 sensor s to keep the mixture at
14.7 to 1 or stoich

there is not going to be any gain in FE
the 02 sensor will report a slight change in the mixture
and
the ECM will adjust using first Short term fuel trim
then long term fuel trim

end result
under the same conditions -
fuel added through the vacuum lines plus fuel from the fuel tank
will add up to the exact same amount of fuel used prior to the
"modification"

there simply is not another possibility .
this is blarney proposed by someone who does not know how the system works .

case closed .

[stovie]

first off jim-bob the ball valve is going to be placed inline of another tank that i'm adding made from a dead compressor that i have so it can handle the vacuum pressure and i also said i'm getting a vacuum pump there's 1 online that i want that goes to 35 inch pounds of vacuum and it's going to go after the ball valve from the tank, so in other words it's going to go tank, ball valve vacuum pump then into the motor and it's all going to be with 1/2 inch line

second the vacuum line i connected to is from my evape canister and it connects to the center of my intake manifold, i used a QUART JAR and a hose line then just t'd into the vacuum line

oh and mwebb i only used about 1/3 of a gallon on 3/4 of a tank!!!

this tank is a little bit less then expected (between 24 and 26) but thats because it's been 60% highway driving witch doesn't allow enough vacuum on my jeep to evaporate the fuel very good at all it needs to be as close to idle as possible to be most efficient it's only about 4 - 6 inch pounds of vacuum at cruising speed

[Jim-Bob]

HUH? How the hell did you only use 1/3 of a gallon on 3/4 of a tank? Did the tank suddenly shrink as a result of your experiment? You still have not explained WHY this would work. What theory are you operating off of? As mwebb (a respected member of two forums I am a part of) said, the ECU will compensate for whatever you are doing through the O2 sensor. So, unless you change the fundamental nature of the engine you are using through modifications that alter it's combustion efficiency, nothing you have described has any basis in scientific fact that would lead to it working. Please provide ACTUAL data points to substantiate your claims and prove that this is not more quackery like HHO generators or magnets on fuel lines. Otherwise, no one on this board (or any other that is populated by intelligent people) will believe a word you say.

[some_other_dave]

Did anybody notice this part of the original post?

Originally Posted by stovie

... it only really gives my the gains in economy if i hold a sufficiant amount of vacuum.

I think we may have hit upon the source of any increase in economy... Driving with a lighter foot!!

-soD

[Ryland]

The reason that this would show some improvement at all is that it is feeding vaporized fuel in to the engine, granted it is only a small amount but it is there and vaporized fuel is going to burn quickly and help to speed flame spread, so there is something behind his idea, same idea as heating your fuel, only he is boiling his fuel by putting it under a vacuum.
but as I said before, when you do this you end up with the less volitial parts of the fuel being left behind, so you end up with a tank of varnish and goo.

[Frank Lee]

Sooo... introducing fuel to the intake via vacuum port gives it different and superior properties than otherwise? Evidently the regular carb or EFI should be done away with...

[max_frontal_area]

i have a supermileage carburetor book in which a coupa designs are vacuum type carburetors. incredible mileage is possible if all gasoline is vaporized, but exposing gas under a vacuum or preheating it can be dangerous.
smokey yunick took an 80's chevy to a hundred MPG by preheating fuel.

think this is the link: http://www.rexresearch.com/yunick/yunick.htm

personally i felt carburetors were never fully explored.
i once heard of a 70MPG carb having been left on a 70's dodge pickup and accidentally slipping off the assembly line...
chryser got wise to its mistake and offered a brand new top of line truck in exchange for carb alone - to no avail!