Ask the Best and Brightest: Kill Mid-Grade Gas? E85?
Published: March 22nd, 2008
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From TTAC reader Ian Opp: "With all the talk about gas prices, etc. why is mid grade still being manufactured? I understand that most cars are either biased towards reg or premium, so wouldn't it behoove us to scrap the whole idea of an 89 octane?" To which I'll add a sub-question: what about substituting an E85 pump? According to the the ethanol industry, you can get better fuel economy with ethanol than regular gas. No, really; they actually want you to believe that. Check out this study from The American Coalition for Ethanol (link to the full report at the bottom of the press release). Are you craving corn juice?
More by Robert Farago
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One of the interesting things to know is that "mid" grade is NOT 50% premium and 50% regular. It's more like 75% regular and 25% premium. So it usually IS possible to save money by blending your own mix.
I buy midgrade instead of having to put premium in. Its a good way not to have the knock sensor kill performance or have the valves knock by using lower grade gas in higher compression engines.
oh and for the record the 3 grades I see here are 87 89 and 93. So for example I might see $3.13 for 87 octane $3.23 for 89 octane $3.33 for 93 octane
1) The blend of low grade and high grade to get your mid grade is dependent on the actual octane levels of the low and high! For example, if you have 87 and 93, then you blend 60% low grade and 40% high gives you a mid grade 89. Some gas stations blend mid grades on their own--others buy mid grade from the terminal. But the terminal blends mid grade this way as well. 2) Ethanol has a higher octane rating, but a lower energy content than gasoline. That means that it pings less, but it will give you a lower gas mileage. E85 yields about a 30% decrease in gas mileage over pure gasoline. Generally most people cannot detect the gas mileage difference between pure and E10. This is evidenced by those who believe that they get more gas mileage with the E10. The laws of physics generally contradict this result.