probaly a stupid question but have never done it and was wondering what is the best way to calculate your gas mileage as accurate as possible.

 

next time you get gas, reset your trip mileage, and make sure that your tank is full.

then drive on that tank until you need to fill up, and pay attention to the trip mileage and the exact number of gallons. say that you drove 301 miles and when you filled up the second time, it took 16.235 gallons, you would divide the mileage (301) by the new fuel amount (16.235).

so, 301/16.235 = 18.54 mpg.

 

it's one of the more expensive things you can do to a truck

 

If you have changed your tire size a lot it will skew your calculations.

 

Only if you didn't recalculate. As long as your speedometer is correct you should be fine.

 

When you say "recalculate" what are you refering to? Is there a way to reprogram things for the different tire sizes?

 

yea, most of the programers will do that

 

You can reprogram the speedometer for different size tires yes. This can be done at the dealer if they know how to do it. It can also be done via a Hypertech programmer. Thats what I used. There is also a thing is it a superlift or something that makes a thing that just reprograms the speedo? Someone makes one that just does that. Then there is the Superchips which I would think would do it but I'm not 100% sure as I haven't used one. There are several different ways to go about getting the speedometer recalculated for bigger tires.

 

The above is how I do mine, but it is far from a perfect method in my opinion. The perfect method would be if you could fill your tank up to the exact same volume everytime. That way, your starting point is always the exact same. This makes your mpg calculations more accurate because your starting out with the same amount everytime. The amount you put back in after driving would be a more accurate indicator of what you actually used. Using the previously mentioned method though, the amount you get in your tank on each fill up can vary from station to station and probably from pump to pump. How full your tank gets all depends on when the nozzle clicks off. So your are never getting the exact same amount everytime (it's close, but not exact).

To help make it a little more accurate, I will sometime:
-gas up at the same pump at the same gas station (as much as possible). This (in my opinion) helps make it more likely that the point where the nozzle clicks off is about the same each time I gas up.

-I also pump the fuel in on the slowest flow setting of the nozzle, mainly at the end when i'm approaching the point that the nozzle clicks off. Imagine pouring milk out of a jug into a glass with the goal of getting the glass as full as possible. If you let it glug glug out of the jug at full force, and then you suddenly stop pouring, you're going to be left with some space at the top of the glass once the milk has stopped sloshing around. If you did this method again on the same glass (empty again), the space might be a little different then it was the first time because it is hard to shut off the strong flow of milk at the exact same place everytime. But if you pour it in at a slow pace, you can pour right up to the very top, leaving virtually no excess room in the glass. And you can do this same method over and over again, making it so that your glass is always filled up to virtually the same point each time. This is how I invision the fuel flowing into my tank, and why I use the slowest setting on the nozzle to pump in the gas (at least when it is almost to the full point). Or, you could do it by hand (not locking the handle button on the nozzle), and as you near the almost-full point of the tank, restrict the flow way down and trickle in the last bit until the the nozzle clicks off normally. The point is to ensure that your filling it up to the same point everytime. I don't think you get that result if you are pumping the fuel in at a high flow rate.

I know this seems really ****, but i'm an engineer by trade, so I think about stuff in this way. The point is, your MPG reading will be more accurate if you're starting with the same amount of total fuel everytime.

 

wow, no one has ever made pumping gas sound so difficult.

Just messing with you Silver