Hi again, e30!

[Mega ST]

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

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

 

[Dialcaliper]

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.

Actually, I think there’s a point on that paper I initially missed. The table is not the “standard”, it’s the actual average octane rating of the fuels tested, which is necessarily higher than the labeled minimum.

What actually appears to be the case is that there is no actual minimum Octane rating that the EPA requires for Ethanol blends

 

[Wolfsbora]

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

I only recently started seeing the same but not always. I’ll get back to you after I take the car for a spin.

 

[FJ16]

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.

 

[gtx3076]

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.

Theoretically a car could get equal or better mileage on ethanol, but not with all things being the same. It would need higher compression and proper tuning that wouldn’t be safe for a lower octane fuel.

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

 

[Wolfsbora]

Had a little fun yesterday for my first time back to e30 in a very long time. The biggest difference I have found going from stage 2 93 octane to e30 is much strong pull in 3rd gear. For me, first and second always had the strongest pulls and although third still doesn’t match them, it comes in a very close third (no pun intended). It’s great to be back!

 

[FJ16]

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

My only real cost of E30 in terms of MPG is convenience, having to fill up more frequently.

My mileage may have dropped from 29.9 to 27.0 (10% just to make it easy) but the cost savings was more than that - in my area it's a 15% drop in price. Perhaps this is just a midwest thing where E tends to be cheaper, but I'm actually getting more torque and saving a little money... at the cost of having to gas up a little more often.

 

[esp_martin]

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

Frequently Asked Questions (FAQs) - U.S. Energy Information Administration (EIA)

"The energy content of ethanol is about 33% less than pure gasoline. The impact of fuel ethanol on vehicle fuel economy varies depending on the amount of denaturant that is added to the ethanol. The energy content of denaturant is about equal to the energy content of pure gasoline. In general, vehicle fuel economy may decrease by about 3% when using E10 relative to gasoline that does not contain fuel ethanol."

edit: i've run about 8-10 tanks of e30 and in my personal experience the above quote tracks with what i've observed in my own car in a reduction in MPG (30ish mpg on 93OCT vs 25ish on e30)