Math, my Mileage and Ethanol Question

[straightshooter1]

Sitting here trying to figure out the answer and having trouble with it.

Yes, I am a pre-calculator guy (bought my first one for grad-school in 1977) and, Yes, I remember slide-rules, but sure never owned one.

I am sure this is simple, but still is over my head.

Okay, remember the thread on ethanol vs. no ethanol?

I've gone through two tanks on non-ethanol. My first gave me only one mpg better, but the second was much better.

Here's my question with all the info I can think of to solve it.

Ethanol treated gas is $386.9 per gallon.

Non-ethanol gas is $416.9 per gallon.

I got 19.1 mpg around town (everything is around town in TampaBay) with my last tank of ethanol.

I got 23.82 mpg around town with my second tank of non-ethanol gas.

What does my mpg have to be to make purchasing non-ethanol cheaper than purchasing ethanol gas?

I have an 18 gallon tank, if that makes any difference.

Then, if someone can solve the first question, I have a second question.

How much difference in price between ethanol and non-ethanol do I have to maintain in order to be economically viable buying the non-ethanol?

It's .30 per gallon more expensive now.

Thanks for at least looking at this.

Bob

[s&wchad]

Originally Posted by straightshooter1

Ethanol treated gas is $386.9 per gallon.

Non-ethanol gas is $416.9 per gallon.

I suspect you slipped a couple decimal points.
Based on your numbers:
Ethanol cost = 20.3 cents per mile.
Gasoline cost = 17.5 cents per mile.

[straightshooter1]

Yes, I did "slip" couple of points. I guess I wrote it like we say it, rather than the right way.

So, at this price and with this mileage, I am ahead of the game.

Bob

[thearborbarber]

My math says you need an 80 cent price difference to break even on ethanol.

[m1gunner]

For a less than 8% increase in price over alkie fuel, you are getting more than a 25% increase in gas mileage.

Can you see why these figures aren't made public?

[DeathGrip]

Bob,Where do you buy this real real gas?I think my Dad's truck needs some.'66 F-100 Big block/4-speed.

[DeathGrip]

You didn't say what you were driving.No real math but a concern about the older stuff.This could far outweigh mileage issues.Unless we think about the price of keeping a car for a long time.Yet most people don't buy a car and expect it to last much further than their first wash and wax.

[oldRoger]

Bob;
I consider Ethanol to be a wonderful thing in Scotch Whisky and a curse as a component in motor fuel.
However I think it unlikely that your nearly 25% improvement in fuel economy will hold through several tanks, remember average the mileage for several tanks, about 100 gals would be a fair test.
I am assuming that you were using the typical gas/ethanol blend which may be up to 10% ethanol.
Real world experience for this stuff compared to gasoline is more usually in the 92-95% range. Thus if the real thing gets you 23.8, you could expect 21.9/22.6 with algore wonder fuel.
With an 8% price premium you are probably just about breaking even
I do have a slide rule, I keep it in a glass front case marked “In Case of Emergency”.
Roger

[m1gunner]

Think of the gasahol this way, it has about double the alcohol of beer. Can your truck get arrested for driving under the influence?

[m1gunner]

Originally Posted by oldRoger

Bob;
I consider Ethanol to be a wonderful thing in Scotch Whisky and a curse as a component in motor fuel.
However I think it unlikely that your nearly 25% improvement in fuel economy will hold through several tanks, remember average the mileage for several tanks, about 100 gals would be a fair test.
I am assuming that you were using the typical gas/ethanol blend which may be up to 10% ethanol.
Real world experience for this stuff compared to gasoline is more usually in the 92-95% range. Thus if the real thing gets you 23.8, you could expect 21.9/22.6 with algore wonder fuel.
With an 8% price premium you are probably just about breaking even
I do have a slide rule, I keep it in a glass front case marked “In Case of Emergency”.
Roger

The mileage hit really depends on the fuel system in the vehicle. Older carbed motors seem to be affected under 10%. But the newer computer controlled systems really get hammered. My personal experience on several newer cars over 5 or more tankfuls shows a 20%+ reduction in fuel mileage. These have all been 4 bangers.

[straightshooter1]

I'll try to answer the questions.

The only place I know of in the TampaBay area to buy non-ethanol gas is Bollinger's Sunoco, located in western St. Pete on Tyrone Blvd., just west of 38th Avenue North. I only found them as the local paper ran an article on them a couple of weeks ago. Turned out to be a block from my Church, so it wasn't inconvenient.

EDIT: I googled ethanol-free gas and found a couple of other stations in St. Pete and several in TampaBay that sell this gasoline. You have to sort out the marinas and wholesalers, but it's not a long list. Bollinger's is still the closest to me.


I have a 2007 Pathfinder, with a V6 engine. I bought it in April, 2007 at auction and it had 25K on it. It now has 108K. I drive a lot for an old retired guy. Even with the rising price of gas, I will probably not curtail my driving as I shoot every single day that I possibly can and at my age and having some health issues, I want to play as long as possible.

I have always gotten pretty good mileage with it. I get 18-19 around town and 24 or more on the road. Nissan recommends premium fuel, but I used to fill up once with premium, then three times with regular (the Nissan service manager recommended that). The non-ethanol gas is regular, but I saw today that they had premium for $4.469 . I think I will stick with regular. I have a couple of stations I used for ethanol, but they are just convenience stores with pumps, Rally, for example. No name brand gas. I used to use Mobil, but my mileage was a bit less and the price was always the same or more.

I drove to Illinois the past three summers to shoot at the Grand American Trap Shoot in Sparta and, with lots and lots of flats (cases) of shotgun shells, clothes, shoes, cooler and two hard cases with guns and extra barrels. I got from 24 to almost 26 mpg. Most of the time, between 24 and 25 mpg. A small part of that is mountains in Kentucky and Tennessee. On the way home, the Pathfinder has less shells in it , but I usually have many bags of lead shot and powder so the weight is even more.

The folks at Bollinger's told me that it takes about three tanks of their fuel to reach the max mileage. After only getting 1 mpg better the first tank, I thought maybe they were just saying that to get me to buy a few more tanks, but today sorta convinced me that they may be right.

I am taking a short road trip to Dunnellon over the Memorial Day Weekend to shoot in the Spring (Trap) Championships and will see what my mileage is going up, then what it is on the way back (I'll have to gas up there with ethanol-I think).

I talked to one guy who was gassing up at Bollinger's who said his Ford Ranger got 25 plus mpg with four people in it and the bed full of stuff on a road trip from St. Pete to Cape Coral (mostly interstate and about 250 miles there and back). My wife's, which is a Mazda clone of the Ranger, but only a two seater, gets a whole lot less mileage using ethanol. She is thinking about trying the gas at Bollinger's too.

There used to be a marina where you could gas a car up with ethanol-free gas, but I am not sure they still let that happen.

So far, so good with this gas.

Roger, I will try to keep track of the mileage over time and tank fulls-unless I abandon the project. I want to talk to the service guy at Nissan (I trust him) next time I am in and ask his opinion.

Bob

[DeathGrip]

Thanks,Bob.

[JohnnieB]

Originally Posted by straightshooter1

.........The folks at Bollinger's told me that it takes about three tanks of their fuel to reach the max mileage. After only getting 1 mpg better the first tank, I thought maybe they were just saying that to get me to buy a few more tanks, but today sorta convinced me that they may be right...........

Unless you drain your tank, it will take multiple fill-ups to remove all traces of ethanol from your fuel. How many depends on how empty your tank is when you fill up with the good stuff.
For example: Your tank is half full of 10% Ethanol and you fill up with pure gasoline. You end up with a full a tank of 5% Ethanol.
If you do the same thing the next time your tank drops to half full, you'll be burning 2.5% Ethanol.
The next time it will drop to 1.25% and so on.
At some point, further reducing the amount of Ethanol in the fuel no longer improves gas mileage.

Also, it may take your vehicle's fuel management computer some time to acclimate to burning the good stuff.

[straightshooter1]

Thanks, JohnnieB.

I tried to get my tank very low before I put the first non-ethanol in.

Thanks for the information on the computer. That's something the folks at Bollinger's said, too, but I didn't know if it was hype or not.

Bob

[oldRoger]

There are two problems with Ethanol as an additive to gasoline from the fuel economy standpoint. There are of course lots of other negatives from the cost and environmental aspects.
First; ethyl alcohol has a lower specific energy content (BTU/Gal) than gasoline.
Second; Ethanol is very hygroscopic. (That’s why Ever Clear is only 190 proof not 200).

So we displace up to 10% of our gasoline with this stuff we will lower our mileage by some fraction. Further, the water which does not mix well with gasoline, does mix well with the 10% ethanol mixes. This water has to be heated from ambient and to the exhaust temps which requires BTUs.
The unknowns are what percent alcohol and how much water, these unknowns prevent us from getting a really good milage answer, but they are negatives.

This is a solution only a politician could love, a lose, lose everywhere but the road to nomination to office and when collecting contributions.