Calculated MPG

[Charlie1717]

My Festiva is the weirdest car I've ever owned for MPGs. Doesn't matter if I take it slow and easy, or run 80-85, it seems to always work out to somewhere around 41.5- 43 MPGs.

Sounds like a good problem! But yeah It hasn't seemed to really effect my mpg... Time will tell as I don't drive very often being in college. Can't wait for Christmas break so I can keep working on the festy! To bad I'm poor ha

[batstiva]

Larger tires will negatively affect your MPG readings because the car is traveling farther per wheel revolution than the odometer will show. It's not much, depending on what size tire you are running now, could be in the 3 to 5% range. Doesn't sound like much, but add it up over 300-400 miles and it does make a difference.

My Festiva is the weirdest car I've ever owned for MPGs. Doesn't matter if I take it slow and easy, or run 80-85, it seems to always work out to somewhere around 41.5- 43 MPGs.

[GenevaDirt]

would depend on the type of driving you are measuring , if it is a lot of stop and go....it will hurt you...if it is a lot of freeway....it can help.

[Charlie1717]

So I started to keep track of my miles vs gallons used to see how my festy was doing. I figured it wouldn't be great since it's a 4 speed and I do a lot of interstate driving. But I calculated it two separate times. The first run I got 43mpg but it wasn't a very accurate due to it only be for about 100 miles but my second time I drove about 350 miles about 160 miles interstate 80 miles highway and the rest was in town. I got 39.4 mpg which I'm happy with.

Also I recently put 13 inch rims on the front but still have the twelves on the back both are 155/80... Do the 13 inch rims improve my mpg or hurt just out of curiosity? My speedo is now off by about 3mph slow.