How to calculate without filling up to full?
 

On average I drive 500 miles a month. With my new hybrid civic that could mean filling it just once a month. I figure with such a long period between fill ups it would be more efficient to not have to fill up all the way and carry all that extra gas around. But if I do this I'm not sure how it will affect the numbers I put in the mileage database. I suppose my second tank has to be a total fill up just to figure out how much my first tank was. Any thoughts? Weight savings in gas not worth the effort?

Re: How to calculate without filling up to full?
 

I haven't run my FEH all the way down yet. By using the Mileage Database on this website, I've been able to see my mpg very easily, even though I've never run to empty.

I agree with you. I don't like running the car to empty for several reasons. If you keep a record of the mileage (I use the Trip odometer for the tank mileage) and how much you put in, seen on the pump, then you can easily figure out the mpg that you get. I let GreenHybrid do the math by putting my mileage on their website.

Re: How to calculate without filling up to full?
 

That's my thoughts, exactly!

If you keep it at maximum 1/2 full, you'll be saving the weight of about 5-6 gallons of gas.
On the other hand you'll be filling up twice as often to do this, and visiting the gas pump less often IS one of the joys of this car!

Enjoy. Maybe I'll see you around North Dallas! What color is yours?

Re: How to calculate without filling up to full?
 

That is a little extreme. In aviation, it makes sense when operating at gross weight and high density altitude. You're looking at ~6.2 lbs per gallon. For an 11 gallon tank, saving half of the weight, 5.5 gallons, saves 35 lbs.

Bob Wilson

Re: How to calculate without filling up to full?
 

Well twice as often for me would probably be every 2 weeks which is fairly typical. I guess since the Civic has such a small tank filling it half way won't make much difference (I read somewhere every 100lbs shaves 1% off FE). My previous car was a 95 Camry and I could tell a difference if I filled that tank to full versus 1/3 full I usually kept it at (about $10 worth of gas). Not keeping the tank full also makes me think a lil more about making medium long trips (1 hour) as doing so almost automatically requires a fuel up versus just making the trip without thinking about it.

Gumby:
Mines is alabaster silver, I usually take Plano Road on the way home. I used to take a backroute on the way to work because of the convenience of ATM and Post Office on the way but after I got my car I did some experimenting and found out I get better fuel milage going up Greenville. The new route has just as many stops but they're all clumped together in downtown Richardson. I find I can more than make up for that with the longer stretches of emptiness once you get past Arapaho.