Weight reduction: not filling the gas tank

[krousdb]

Originally Posted by MetroMPG

As Dan knows, you can gain an equivalent weight advantage by just not filling your tank above half way.

Yup, about 6 lbs per gallon IIRC. When not calibrating the SuperMID, I only have 6 gallons max in my 11ish gal tank. That is about 30 pounds savings. I also have my windshield washer solvent at 1/2 tank max.

[MetroMPG]

Originally Posted by krousdb

Yup, about 6 lbs per gallon IIRC. When not calibrating the SuperMID, I only have 6 gallons max in my 11ish gal tank. That is about 30 pounds savings. I also have my windshield washer solvent at 1/2 tank max.

I love it. Are you running half-tanks now, or are you still calibrating the MID with the VX?

I think 6lbs/gal is what I turned up most in a recent search I did as well. Which actually makes fuel the single heaviest easily "removable" item on my car. 10.5 gal tank = 63 lbs. Spare & jack = 24. Passenger seat = 29.

[argylesocks]

Originally Posted by MetroMPG

I love it. Are you running half-tanks now, or are you still calibrating the MID with the VX?

I think 6lbs/gal is what I turned up most in a recent search I did as well. Which actually makes fuel the single heaviest easily "removable" item on my car. 10.5 gal tank = 63 lbs. Spare & jack = 24. Passenger seat = 29.

how much difference does 30lbs really make??

for what its worth, i skipped breakfast this morning. figure it was worth a couple of pounds.

[krousdb]

Originally Posted by MetroMPG

I love it. Are you running half-tanks now, or are you still calibrating the MID with the VX?.

I'm calibrated and running half tanks now. Can't say it it makes a difference. Can't hurt though.

[Ted Hart]

Originally Posted by theclencher

I wonder if the increased fuel sloshing around when at less than full causes more evaporation?

For..."theclencher"-
And, where is this "evaporated fuel" going to go? A volatile liquid ...in a closed container... rapidly saturates the space above the liquid...and, as such, the space cannot take any more molecules of vapor. Unless you heat the liquid. Then, the vapor pressure goes up...to equilibrium. The molecules jump out of their liquid state...and saturate the space above... until equilibrium occurs, then everything stops. The fuel won't evaporate in a closed container.

[zpiloto]

I experimented with this(nothing hardcore just comparing tank averages) running several tanks with 5 gallons compared to the usual 15 gallons with no noteable increase in FE. It does accelerate better but I didn't like filling up every 3-4 days.

[MetroMPG]

Originally Posted by zpiloto

I experimented with this(nothing hardcore just comparing tank averages) running several tanks with 5 gallons compared to the usual 15 gallons with no noteable increase in FE. It does accelerate better but I didn't like filling up every 3-4 days.

Not surprised it didn't show up as a measurable increase.

If we take the conservative side of EPA's claimed 1-2% FE penalty from 100 lbs extra weight, then you'd increase your fuel economy by .3% if you drove around with 30 lbs (5 gals) less fuel in the tank. That's easily lost in the noise, even with instrumentation.

But it's still a real gain. Weight reduction is common sense.

[MetroMPG]

25 lbs may represent a fuel economy difference of about 0.25% - 0.5% based on the oft quoted figure of a 1-2% fuel economy penalty for every extra 100 lbs carried (EPA).

The difference is likely too small to measure reliably with FE instrumentation in a test scenario. But it's real, and every little bit helps.

However, this kind of discussion is probably an example of how we apparently cultivate the impression we're Screwballs.

[SVOboy]

Is dan back from retirement? Retirement meaning the beach.

[GasSavers_Jack]

I make up for full filling my by just running it 50 miles after the fuel light comes on!