vacuumizing fuel for better economy

[stovie]

has anyone else added a quart jar of gas to the vacuum lines of the car???? i did and got about 7 mpg increase on my 1997 jeep grand cherokee the only bad thing is that it only really gives my the gains in economy if i hold a sufficiant amount of vacuum. I have a 8 gallon compressor i modifide to fit under my jeep that i'm going to fell with 5 gallons of gas and i want to add a 35 inch pound vacuum pump to it and have a ball valve to control the amount of fuel the pump sucks out by connecting the ball valve to the throttle so i have gains throughout the throttle position.

[Frank Lee]

[MetroMPG]

Originally Posted by stovie

has anyone else added a quart jar of gas to the vacuum lines of the car???? i did and got about 7 mpg increase on my 1997 jeep grand cherokee

I think what Frank is trying to say is: sounds a lot like nonsense.

[Ryland]

How does it compare to dumping the quart jar of gasoline in to your fuel tank?
Basically what you are doing is vaporizing the fuel, leaving behind the thicker varnish.
The good way to truly test this would be to put a valve on your vacuum line so that while you are driving you can disconnect it, otherwise you are just adding fuel vapor to your intake and at that point the question is, what are you going to do with a tank or jar of varnish? most modern cars already run with the fuel tank under a slight vacuum to prevent vapor emissions, you are just taking it to the extreme and causing the fuel to boil in your jar.

[UFO]

I'd like to know how on earth 7mpg gain was calculated.....

[stovie]

Originally Posted by UFO

I'd like to know how on earth 7mpg gain was calculated.....

21mpg to 28mpg/24 gallon tank to 680 miles!!! i'm 3/8's the way through a tank and i have 320 miles

i know it sounds ridiculous but i'm getting that fuel economy and i'm not doing anything else but acetone it does drop the FE quit a bit driving on the highway though cause i have to stay at a TP that has to low a vacuum to work efficiently

[MetroMPG]

How to properly test modifications (AKA: don't believe every MPG claim you read)

[Old Tele man]

...LOVE Stan Laurel & Oliver Hardy!


...HATE snake-oil MPG contraptions!

[t vago]

I dunno...

On the one hand, it might possibly (and I am going out on a limb here) be a rather novel form of heterogeneous charged combustion. That is, a pocket of stoich air/fuel mix is developed within a homogeneous mixture of much leaner air/fuel mixture, and the result is burned within the combustion chamber. The stoich pocket reliably ignites, and reliably burns the rest of the mixture inside the chamber. Modern cars with direct injection can do this easily.

On the other hand... Well, there is the question of the procedure used to test this claim. I am pretty skeptical right now.

[bestclimb]

Originally Posted by stovie

21mpg to 28mpg/24 gallon tank to 680 miles!!! i'm 3/8's the way through a tank and i have 320 miles

i know it sounds ridiculous but i'm getting that fuel economy and i'm not doing anything else but acetone it does drop the FE quit a bit driving on the highway though cause i have to stay at a TP that has to low a vacuum to work efficiently

Judging by the fuel gauge is a sure way to see whacked out data. Extrapolating from gauge position is an excellent way to exacerbate that whacked data.

Case in point

In my civic I have a 11.9 gallon tank. I can go 150 miles at 50mpg before it drops off of the full peg (that's 3 gallons used gauged by an MPGuino). If I use an extra gallon to go to 200 miles it drops to just above the 3/4 mark. If I look at the fuel gauge at that point it looks like I have used only a quarter tank on the gauge which is just shy of 3 gallons. 200 miles by 3 gallons is 66MPG that is about a 15 mpg error if I go by the gauge.

Moral of the story is get an average of a couple tanks with the mod and without as a bare minimum for getting an estimate of the effectiveness of your mod. It would be better if you could eliminate the variables of changing driving conditions but we know that it is not always possible when testing a mod for your self. Gauges are indicators, right now you have an indication of a great boost in mileage we are looking forward to some real data. Don't forget to include the fuel you are sucking in the vacuum lines in your total fuel for the tank.