That sucks about your closest station :(

As for 89 octane? that's not really a fuel type, it's usually a mix of a higher octane and 87 that's combined at the pump.

Wow thanks for the Pure-gas link! Didn't know about it and it turns out there is one just two streets down from my neighborhood exit.

I'm sad to hear that E15 made it through. I hope it at least gives a decent drop in fuel prices. I'd be so pissed if prices stayed the same.

It will have no effect on octane in terms of what you get at the pmp, because AKI will be determined based whatever the blend is -- meaning the effect of ethanol will already be accounted for (sort of -- see below).

My only concern is the lack of consistency in claimed ethanol content -- pumps typically report UP TO some amount of ethanol (at the moment, < 10%). So are you getting 5%, 8%, 9.9%? It's unknown, and there is no information made available on how much variance is considered acceptable.

If we go to E15, that is a bump of 50% more ethanol... so now the range is potentially greater, and the lack of consistency from pump to pump is potentially greater.

the problem with the low ethanol blends say e10 e15 is that they MAINTAIN the same octane as regular unleaded. this is why they are cheaper. the only way you can stay around 85 octane with 15% ethanol is if you start with low grade gasoline. they use cheaper fuel then mix it with even cheaper corn fuel and you ed up with an 85 octane gas with less eneregy than standard 85.

Not exactly sure what those last two posts are saying, but;

The octane rating is tested, it will always be what they say it is, it's the dept. of agriculture that checks it.

The problem has nothing to do with octane, it's to do with the energy contained in the fuel, the more ethanol in each gallon of fuel, the less energy that gallon of fuel produces. If your engine is giving you less power, you open the throttle more to get the same, be it accelerating, or even just cruising. That's why the gas mileage goes to pot with this crap.

The more ethanol content in gasoline, the less powerful it is (wikipedia tells me that E85, standardized to gasoline, produces 30-35% less power). Hence, the energy density of ethanol is lower than gasoline. Basically, you need to burn more of it to get the same power, meaning more throttle and more fuel do to the same thing with E10 than E15. For that reason, E85 might be cheaper per gallon, but will be more expensive per mile. I don't think that a percentage difference of only 5 will make a huge difference, but overall, people will see slightly lower fuel economy.

The VQ37 is 11:1 comp ratio for gasoline, which is actually pretty high (few cars have a compression ratio this high, although they're more common as fuel economy is being maximized in this country; consider Mazda's SkyActiv technology, with 14:1 comp ratio). If we run E85, where octane numbers are estimated to be approximately 100 or more, we'll have less knock, which I guess someone could modify their Z's to be run on E85.

But since E15 has been approved, we're going to pay the same price for worse gas. It has less fuel and more of the cheap, rather useless ethanol. There's not nearly enough ethanol in E15 to make a difference from E10, it just means we get less actual fuel.

Is 87octane ethanol free going to knock?

All but 1 E-free gas stations only carry 87; Gulf, Citgo, and a few "unbranded" stations. And a Sinclairs that has 93. Also I worry about gas quality from these places as opposed to my usual shell. There's a shell with E-free 93 about 30miles away that I will buy from when I can.

So what is the bottom line here? All I care about is my car NOT being slower. How do I prevent that? I'm guessing based on the posts the only way to do that is to go FI or get higher compression internals?

HP will not be affected as much since its only e15. Gas mileage will suffer slightly.

pure-gas isn't always up to date. There are two stations in my area that aren't on there, so....take it with a grain of salt.

Well that's a relief if true....but all the posts above say that we will make less power. Can someone please clarify?

Somebody plz explain this! I need to know if I have to start saving for a turbo!

I promise the ECU will compensate for the extra 5 percent of ethanol content. We are already on e10. e15 will not do much worse. Actually, if our cars were boosted, it would help. Also, the ECU will be able to compensate for closed loop operation. The o2 sensors will pick up the swing in fuel and adjust accordingly via the fuel trims. This is where the gas mileage gets a little worse. WOT might lean out a hair, but that can be a good thing. Emphasis on "can", depending if your car has already been tuned or not.

So is this something to legitimately worry about? Also what do I have to look for at my local gas stations in order to tell? Also why is the government ok with this reducing fuel economy, but it is forcing car manufacturers to sqeeze out more MPG? I hate this FN country more and more each day.

Maybe no E15 after all???? maybe!

The White House May Waive The EPA's Ethanol Requirement