Friday, June 13, 2008

Slower But More Hyper

I have continued trying to squeeze more mileage out of my car. So far it’s working great! OK, I'm going to get all math-y here for a minute (I have retained some of my engineer training).

I drive a 1998 Toyota Corolla (sexy, I know. But it’s paid for, and I’m beyond caring about what kind of car I drive). With my previous driving habits I usually got about 28-31 miles per gallon overall. I probably do about 75% of my driving on the highway. I’m going to say my baseline mpg is 29.5 mpg.

I have a 12.4 gallon gas tank. I used to have to fill up when I would hit about 330 miles driven on a tank. For my first tank after changing how I drive, I went 374.4 miles before having to fill up. I put in 11.0 gallons, so that works out to 34 mpg. So, dividing 34 by 29.5 results gives me a 15% increase in gas mileage. Not too shabby. I drive about 1600 miles per month. At 29.5 mpg that’s 54.2 gallons of gas. At 34 mpg that’s 47.0 gallons of gas. So if I got 34 mpg from here on out (very doable) I would save 7.2 gallons of gas per month. At the current price of $3.93 per gallon, that saves me $28.30 per month. That’s $339.60 per year. Not a fortune, but nothing to sneeze at either.

Tank 2 has been even better. I’ve been driving slower, using the AC less, and coasting more. I also aired up my tires close to the maximum air pressure. I got 415.4 miles out of my tank before filling up. With an 11 gallon fill up, that’s 37.8 mpg, which is a 28% increase over my baseline. At 37.8 mpg, I use 42.3 gallons of gas per month. That saves 11.9 gallons per month over the baseline. At $3.93 per gallon, that saves $46.77 per month, or $561.24 per year. Wow! I think that’s pretty impressive given that my car is 10 years old and that the only physical modification that I made was to add more air to my tires.

So I’ve pretty much gone from a speed demon to a grampa driver in the last 3 weeks. But I think getting paid $46 a month in exchange for people giving me the stinkeye occasionally is worth it. Maybe I should start a driving school.


Blogger Deb R said...

Pretty cool, JC!
I still haven't tried this yet. Unlike you, a lot of my driving is in-town driving or twisty rural roads, so I suspect it wouldn't make nearly as much difference for me, but still, I should try it.

6/14/2008 7:17 AM  
Blogger kristen said...

i've thought about this since you posted about it, but have yet to put it into practice because i've got lead in my foot.

6/14/2008 2:24 PM  
Blogger paintergirl said...

ok jc, i'm still trying to figure out the math part. I try really hard not to step on the gas too hard. The (almost)over inflating something that we might try.
You get really good mileage no matter what you do.

6/15/2008 9:55 AM  
Blogger hollibobolli said...

I love that you did all these calculations - but I do the same thing.. remember, I yelled at that lady next to me when we were driving "great, lady - way to burn through your gas!!" You know I can't floor it because it just tears through fuel in the Shreksplorer.. which otherwise gets awesome (aihtw) mileage.

6/15/2008 6:56 PM  
Blogger REENblack said...

LOL I love this post! After your last post about this I've done less and less quick start/stop and tried to coast doesn't do a lot of good with an automatic though. When we eventually get our second car (that will be a big POS), it will most definitely be manual if for no other reason than to be able to coast!!!

6/15/2008 8:06 PM  
Blogger Rebecca said...

you might try replacing the air in your tires with nitrogen. it stays the same regardless of the temp. ian says that the expansion and compression of air as it heats and cools has a great deal to do with the type of gas mileage that you get.

we checked out a smart car last week in knoxville. really cute, but wow, if you were rear-ended, you'd die! no doubt. the only thing that we didn't like is that it's gas mileage of like 33 city/low-40s hwy was based on using top-grade/premium fuel, not regular. so ian is back to wanting a diesel VW bug once we get our other VW paid off. good luck with your tricks & techniques for getting more bang for your buck!

6/16/2008 9:06 AM  
Blogger Cory said...

You lost me at "I'm going to get all math-y here for a minute" =)

6/17/2008 1:15 PM  

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