Hi again, e30!

Thank you all for this eduction! I also track ignition correction on 1 and 4. I now have a better understanding of their importance.

If you have read about the people who use a E30 tune over let's say a 93 tune. They see a reduction in fuel mileage. I have access to 91 non ethanol top tier gas. I get the best fuel mileage in my daily driver from it not really worth the cost though. I am sure there are certain examples on certain engines where if you put non ethanol let's say 85 versus E15 91, 88 in my area though. Maybe the E15 would result in better fuel mileage, because it allows the engine to perform much better than 85 which is horrible. Also when I play around with the octane calculators if I take 87 octane assuming it has ten percent ethanol in it, and I increase it by five percent I get E15 88.26 octane. If I take non ethanol 85 and add fifteen percent ethanol I get E15 88.6 octane. So at the end of the day I call bull on that paper. This article actually says E15 has 88 octane, and it's coming from the State that benefits the most from ethanol. https://iowarfa.org/ethanol-center/e15/e15-facts/

Last thing I will say. I do believe higher octane fuel can result in better fuel mileage. I believe we should actually set a higher standard and get rid of 87 at the very least. This would allow manufacturers to make engines with higher compression and more aggressive ignition timing. Not only more power but better fuel mileage. The Mazda SkyActiv engine has less compression in American than Japan due to the fuel. I don't want higher ethanol fuel though. E10 max.

If you have read about the people who use a E30 tune over let's say a 93 tune. They see a reduction in fuel mileage. I have access to 91 non ethanol top tier gas. I get the best fuel mileage in my daily driver from it not really worth the cost though. I am sure there are certain examples on certain engines where if you put non ethanol let's say 85 versus E15 91, 88 in my area though. Maybe the E15 would result in better fuel mileage, because it allows the engine to perform much better than 85 which is horrible. Also when I play around with the octane calculators if I take 87 octane assuming it has ten percent ethanol in it, and I increase it by five percent I get E15 88.26 octane. If I take non ethanol 85 and add fifteen percent ethanol I get E15 88.6 octane. So at the end of the day I call bull on that paper. This article actually says E15 has 88 octane, and it's coming from the State that benefits the most from ethanol. https://iowarfa.org/ethanol-center/e15/e15-facts/

Last thing I will say. I do believe higher octane fuel can result in better fuel mileage. I believe we should actually set a higher standard and get rid of 87 at the very least. This would allow manufacturers to make engines with higher compression and more aggressive ignition timing. Not only more power but better fuel mileage. The Mazda SkyActiv engine has less compression in American than Japan due to the fuel. I don't want higher ethanol fuel though. E10 max.

Do you see any negative corrections? I always see +2.50-3 WOT.

Do not agree at all. I know on every vehicle I have I would see a reduction in fuel mileage if I were to run a higher ethanol fuel. Just going to have to agree to disagree.

Yeah, this is what I assumed would happen - and it did. My average on a Dizzy 91 tune was 29.9, and on the E30 tune it has dropped to 27.0.

If mileage is a priority, don’t run E30, and stay out of boost.

I probably won’t convince you, but have you actually tried it (for an extended period, not just a tank or two).

Here’s food for thought. When you are able to increase power by advancing timing, fuel and air into the engine *don’t* change. You are literally extracting heat energy that would otherwise combust later in the stroke and just get blown out the exhaust. This is how you can get more power out of E30 and race gas than you would otherwise expect, just by advancing timing.

The same thing happens at any load point, not just at WOT. And since you can get more power out of the same fuel quantity, it very much follows that you can chose to reduce fuel (and maybe air, or just run lean) and increase timing to achieve the same power output, even at light cruising loads.

It is rarely explored in aftermarket tuning, but car manufacturers spend thousands of hours on part throttle tuning engines, and the algorithms that monitor for corrections and dynamically add and subtract timing on newer cars are primarily there to exploit that, not just to occasionally make more power.

I can almost guarantee that most cars that are designed for high octane, but readily adapt to low octane fuels will get slightly better mileage (as well as emissions) on high test. The main problem is that it’s subtle, and usually never quite enough to justify the 5-10% higher cost of premium gas.

When it comes to E15 and E30 fuel economy, remember that standard gas is almost universally E10 already, so it’s not as big a jump as you’d think to make up for the lower energy content of ethanol. It just doesn’t keep going all the way to E85 because at some point with high knock resistance, increasing timing in most cases starts the burn too early and you just can’t make use of the higher octane