MR2 SpyderChat banner

POLL: 87, 89, 91?


  • Total voters
    21
41 - 46 of 46 Posts

·
Registered
Joined
·
899 Posts
You can expect exactly 10% better gas mileage because there is exactly 10% more GAS in your tank. The alcohol doesn't do a damned thing to help the car go forward.

I've kept a detailed spreadsheet of every tank of gas I have put in my car for 5 years like religion. Without any shadow of a doubt, I got 10% better mileage, different octanes had zero effect.

Here's a bit of the accumulated data:

Avg MPG
28.11
Total Fuel $
$4,675.54
Miles Driven
48,117.48
Cost per Mile
$0.70
Total Gallons
1716.44
Avg Cost/gal.
$2.73
Repair/upgrades
$8,244.55
Pure ethanol has approximately 2/3 the energy content (per gallon) as pure gasoline. So the "10% more gasoline in your tank" is not the correct way to figure out the effect of 10% ethanol. All you need to know is that E10 has about 97% the energy content of E0. If the E10 you use has the same Octane as the E0 you are comparing it to, there is no reason why you would get 10% better gas mileage on E0 (pure gasoline).
 

·
Registered
Joined
·
453 Posts
I'm not making any of this up. I have the hard numbers to prove my statements. Direct empirical evidence, gathered by meticulously by me.

So on one hand, we have anecdotal evidence that ethanol has 50% of the energy, and on another hand we have more anecdotal evidence of 66% of the energy.

Who is to say they are putting "pure ethanol" in the gas? To the best of my knowledge, our engines were not manufactured with alcohol in mind. To the contrary, they were in fact engineered to run gasoline.

My point here is these are gas engines, and I choose to run gas in mine. Sometimes it's not available, and every single time I put the crap in, I have measured between 9.335% to 10.275% difference in fuel economy. These measurements were taken over a period of 5 years and just under 50,000 miles.

These numbers definitely don't lie, and neither do I. I have no reason to mislead any of you about this, it would be a waste of my time.

Cite all the other numbers you like, it just seems highly coincidental that what's written on the fuel pump is "may contain up to 10% ethanol" and when I use that stuff I get -right at- 10% variation in the mileage.

As they say on the interwebz, YMMV.
 

·
Registered
Joined
·
899 Posts
I'm not making any of this up. I have the hard numbers to prove my statements. Direct empirical evidence, gathered by meticulously by me.

So on one hand, we have anecdotal evidence that ethanol has 50% of the energy, and on another hand we have more anecdotal evidence of 66% of the energy.

Who is to say they are putting "pure ethanol" in the gas? To the best of my knowledge, our engines were not manufactured with alcohol in mind. To the contrary, they were in fact engineered to run gasoline.

My point here is these are gas engines, and I choose to run gas in mine. Sometimes it's not available, and every single time I put the crap in, I have measured between 9.335% to 10.275% difference in fuel economy. These measurements were taken over a period of 5 years and just under 50,000 miles.

These numbers definitely don't lie, and neither do I. I have no reason to mislead any of you about this, it would be a waste of my time.

Cite all the other numbers you like, it just seems highly coincidental that what's written on the fuel pump is "may contain up to 10% ethanol" and when I use that stuff I get -right at- 10% variation in the mileage.

As they say on the interwebz, YMMV.
First of all the 66% is not anecdotal, it is factual data. So is the 3% overall energy content difference. Secondly, if you really are getting 10% better fuel mileage, than it is probably due to there being a significant Octane difference between the 2 fuels. Other contributing factors is the fact that the repeatability of vehicle fuel mileage measurement is no better than +/- 2% even under laboratory chassis rolls conditions, and that you are not doing the test comparisons as a blind test (unintentional driver bias).

Dave
 

·
Registered
Joined
·
453 Posts
OK, "anecdotal" is the wrong word. It's second-hand evidence, unless somebody here is doing the actual research themselves.

Octane has had absolutely zero effect on my fuel mileage.

Factual data, maybe... if you believe that none of these researchers are in the pocket of any particular company with financial interests in the outcome of said research.

I've been keeping track of my own data and I am the only one who has driven the car for five years. I've burned 1716.44 gallons of fuel to date. My average fuel mileage is 28.11 mpg.

I have no skin in the game other than being aware of what my own car is doing. I get 10% better fuel mileage from pure gas vs. the other kind.

I'm not sure why anybody would argue this point with me. No driver bias, intentional or otherwise. I fill the tank, I enter the numbers into the spreadsheet in my tablet, let the formulas do their thing.

Honestly, the only reason I care about the mpg is because if it goes down significantly, it's an indicator that something is wrong. Gas prices don't concern me in a vehicle with a 12 gallon tank.

And with that, I'm done with this conversation.
 

·
Registered
Joined
·
453 Posts
Negative, I use the highest octane available when I can't get E0.

Usually the E0 is 87 around here at the QT stations but Marathon usually has 90. There are some obscure stations with higher, like 93 or even as high as 100 but I don't see the need for octane that high.
 
41 - 46 of 46 Posts
Top