New record on MPG for me.

[CoastieCosta567]

I know my calculations are good cuz, what i simply do is just fill up the tank to full, restart my trip-meter right when i get back on my VX. Then when i run out completly and i mean almost to the bottom, then i fill up all the way again and see how much i filled up to and then i see what my trip meter said and divid that with how many gallons i waisted and then the answer would pop up. here is an example:

1. I fill up Completly full, and re-start trip-meter.
2. Drive till empty, and go back to Gas station and fill up to full again.
3. So the trip meter said 340 miles and when i filled up again the gas station gallon meter said 19.7g, lets say, now divid those two numbers and it will say
17.3 mpg if u round it up.
4. We all know our VX's hold 22.5g's, so now Subtract 22.5g - to 19.7g, making it 2.8g extra gallons on your tank, before you added gas to find out how much u used in your gas tank.
5. Now you have to times 17.3 x plus the rest of your tank, so that would be 17.3 x 2.8g and that would be 48.4 miles extra you had left on your tank.
6. Now add 340miles plus 48.4miles you had left and that would be 388.44miles on your gas tank full, but wait, there is still 1 more step.
7. Now if you have bigger tires, we all know that the trip meter is reading wrong and your are really covering more ground than what it says, so then you have to do the math on how much you are really covering and add those numbers up and you will get your true Miles Per Tank and your True miles per Gallon.
p.s So in conlusion you are really getting more then 388.44 Miles Per Tank and more then 17.3 Miles per Gallon. This is just a similer example.

you guyes understand?

So just cuz i Can't remember how to do the math on bigger tires, do any of you guys know how to do that with 33 inch tires to find out how mach more you are really covering?

So i guess i would be doing even better with my MPG if i was back in Florida and if i have my little oil and tranny fluid leak fixed.

Oh by the way, i'm getting tranny fluid leaking out of where my Mode position sensor is at. You guys have any idea on how i can fix that?

JHarris, I think you should buy your gas in Indiana. The RVP 7.8 stuff in Indiana is a heavier-molecular-weight gas that doesn't evaporate as quickly as conventional gas does (reduces smog from gas vapors). The ethanol-oxygenated stuff in Kentucky will give you lower mileage. Buy a tank of each and see what your results are. I'd be curious to know if there's any difference between the RVP 7.8 stuff and the fully-conventional gas you can get one county out.

Wikipedia has a decent write-up on gasoline and it's many variations. Here's some California-specific info

Coastie, I thought you were in FL! If you're in SF driving on 5.7% ethanol Cali-gas, I cannot believe that you are getting 18+ mpg. I don't know what's going on with your calculations, and I don't doubt that you are getting better mileage with correct plugs, but 18 mpg doesn't add up.

[JHarris1385]

Chopper - review my thread, it has been updated.

[VehiGAZ]

Okay Coastie, thanks for the full-disclosure update! You are certainly calculating your mileage correctly. But your extrapolation of how many more miles you could have run if you ran to empty that gets you over the 400 mark is what was so unbelievable to us. I don't think it's legit to thrown that in, because the 22.5 gallon tank rating does not translate into 22.5 gal of usable fuel... I can put in 21 gallons if I am sputtering and stalling pulling up to the pump. I am pretty sure any of us will run out of gas before we can burn 22.5 gallons.

Here is a tire-size-discrepancy calculator. If you calculate the difference in circumference on your bigger tires and multiply your odo's mileage reading by that ratio, you should end up with a more accurate mileage calculation.

[JHarris1385]

I think there is a little more math to it than that.....


Edit: I would use...http://www.rims-n-tires.com/rt_specs.jsp take the % figure and times it by your miles. The % is found in the speedometer box after the inputs are selected. If this holds true I just banked 18.138 mpg.

Re-edit: Or here http://www.miata.net/garage/tirecalcold.html.....I got 10.7% on the first site and 18.9% difference on the second site due to my larger tires. Which new quote equals 19.52mpg.

But remember I am in the middle of the acetone trials. I just filled up today with 4oz of the juice.

[taylorRichie]

I averaged 17.4 MPG on my way home from Colorado.

I must be doing pretty good... That drive is far from flat... far from it... plus it's windy in all directions, sometimes it's a head wind sometimes it's a cross wind... etc.

I'm still running on the same tank from Rawlins To Ogden (that's 283 miles) And I think my trip o meter is at ~300 (at the dealer or I'd check exact) And I had a quarter tank (on the indicator) left.

We'll see where I end up...

[Solitude]

I once drove to payson, az from phoenix.. most of the time I was doing over 80mph.. the fuel mileage was under 14..but I got there alot quicker.. LOL..