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Old 06-17-2008, 07:31 AM   #7 (permalink)
EcoModding Lurker
Join Date: Jun 2008
Location: Rhode Island
Posts: 17

Mr. Miragi - '96 Mitsubishi Mirage S
90 day: 27.45 mpg (US)
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Originally Posted by ConnClark View Post
hmmmm..... How does 1/3785th of a gallon additive translate into a 4 mpg boost? Answer: it doesn't. You filled the tank with more gas when you did the acetone test than you did without the acetone. Blatant proof is you have a 3 mpg drop below your base line without the acetone..
This is typical naysayer logic... The percentage of the additive is not what is important, it is the vapor pressure and surface tension of the mixture of gasoline and acetone that gives the boost in efficiency. The drop below the baseline was probably because it takes a full tank on most cars for the computer to adjust the fuel trims for new gas. This is also why most people get best mileage out of the gas station they always go to. Not because the gas is necessarily better, but because the car is used to that particular gas.

Originally Posted by ConnClark View Post
To truly top off a tank you have to fill it to the top of the neck. Then you have to put the cap back on and bounce and rock the car around to get the fuel to displace trapped air in the tank. You will have to do these two steps a few times. I have found I can pack an extra .7 gallons in my car that way. To get a consistent mileage reading you also need to do this each time you fill up. You also have to do it from the same pump having your car face the exact same way to rule out influence of slope of the pavement.
Really bad advice, topping off a tank in this way is extremely bad for your evap system. Please just fill up until it clicks once. If you record your mileage at every fill up and the ammount of gallons it took to get there the resulting average fuel economy will be accurate. Each individual mileage reading between fill ups will vary no matter what you do, but the average of your readings will be accurate when you look at a few fillups.

Originally Posted by ConnClark View Post
Also your wife has a 2006 car and your mileage is only 5.3% above EPA. To do this poor with my car I have to drive around with my foot in it almost all the time and my car was built back in 1985.
For one thing, maybe his wife does drive around with her foot in it. And are you going by the old epa estimates for your car or the new ones. Not to mention, 80s cars are MORE efficient than todays pieces of junk. Trust me also, getting 5% better mileage on a V8 truck with todays emmissions and safety standards without any hypermiling techniques is a serious gain.