Can someone explain Fuelly.com to me?

Threads like this are just fuel for the fire, if you'll pardon my expression, when someone tells me they're getting unbelievably good, or bad, gas mileage.

It's simple.

If you want to know what gas mileage you're getting.

1. You have to start with a full tank. Forget everything you ever knew about how many miles you've gone or how much gas you've ever used. Fill the effing' tank to FULL.

2. Reset the trip odometer to zero.

3. Drive. This part is easy. I hope.

4. Somewhere around 300 miles, give or take, the tank's going to be near empty and it's going to be time to buy gas again. Drive into the gas station. Fill the tank. All the way full.

5. Now, you just bought, say, 20 gallons. And your trip odometer says, say, 360 miles. Fine. You just used exactly 20 gallons to go exactly 360 miles. So you divide the number of miles on the trip odometer, (360) by the number of gallons you just put in the tank (20) and get 360/20 = 18mpg.

6. Zero the trip odometer and repeat.

Fuelly does exactly this except it keeps a running count of the "real" odometer reading, instead of zeroing the trip odometer every time.

Suppose I did not fill the tank to full on that second fill - Hey, I can get some GREAT gas mileage. 360 miles divided by 5 gallons (the amount I put in the tank) = 72mpg!!! You have to fill to the same point - full - every time.

 

Don't confuse the huddled masses, man.

 

Eureka!

 

Jesus Christ this isn't rocket science. You have no other way to know how much fuel you've used unless you fill up all the way (without OBD help). If you don't will up all the way, check the "partial fill up' box at the bottom. Because guess what, you only partially filled your tank. Fuelly will not factor in 'partial' fill ups into your average mpg.

There's no 'future' anything about Fuelly. It uses the miles you just drove prior to fill up, and the amount of fuel used prior to fill up (based on filling up all the way). There has to be a constant in order to base fill ups on. Filling up all the way gives you this constant.

This is the same way any person has calculated fuel mileage since the invention of the wheel. Not just the way Fuelly does it.

 

So much derp

Who woulda thunk entering the mileage the truck says and how many gallons the pump says into a computer could be so difficult

 

I dont understand why this is so complicated, fuelly is extremely simple, you just have to always fill up, I never top off, always fill to the first click to keep things consistent.

Say you fill up to the first click, drive 350 miles and at the next fill up your truck takes 18.5 gallons to the first click. You just drove 350 miles on 18.5 gallons of gas, hence your MPG will be 18.9189 MPG. This isn't rocket science and fuelly is not predicting anything, you just need to always fill up to the same level, if you dont there is no way to accurately calculate your MPGs offline.

Sure this may not be 100% accuarate, but its pretty damn close.

 

+1

 

What if I just used a calculator ?

How does that work again , do I need to fill up all the way everytime ?

 

First you need to make sure your calculator is topped off, be careful though, as most of them run on kerosene these days.

If you can find one that runs on diesel grab it becasue they are rare, a little more expensive but they will run forever.

 

I use Road Trip for the iPhone.
You put in the ODO, gallons and price/gallon every time you fill, even partial.

It does all the rest, duh.

18.97mpg overall
19.65 last fill.

It also tracks maintenance costs, reminds you of pending future maintenance etc...

 

If I use a paper and pen , do I need a new piece of paper each time ?

 

Gas Cubby for Iphone is pretty similar

 

You must fill the paper up completely, a partial filled paper will not give you accurate results .

 

And I wouldn't use a pen, what if you make mistake, you can't erase pen.

Unless you get an erasable pen, but they smudge to easily then you get ink everywhere, this is getting more and more complicated, I need a nap.

 

If you use fuelly, it could predict your mistakes

 

Yeah, but how??

 

Hell, I just use my calculator every few times I fill up. Much simpler.

 

I believe how to compute a simple average is taught in 4th., maybe 5th. grade.
Apparently a lot of the posters were absent that day. Geez!
A sad statement on the status of the U.S. education system.

 

Point out the "lot of posters" that can't compute an average.

The OP certainly dreams that somehow Fuelly can know how many gallons he burned without filling up, but everyone else is saying he is delusional.

Just a chance to ring in on the sad US education system while showing your lack of reading comprehension?