My experience with Ethanol free gas

[y_p_w]

But doesn't denser mean more energy? So with more energy per volume, a potential bigger bang with each revolution?

If so, can't the ECU just compensate and bring in more air when on ethanol free fuel for the same quantity of fuel?

(I have no idea, nor hold any expertise whatsoever on the matter).

No. The fuel's energy density is not the hard part. If there's less energy density in the fuel, it's still a liquid and it's easy to just inject more if more is needed. For example, pure alcohol engines (think IndyCar) can be really powerful even running methanol with considerably less energy density than gasoline. But I believe the big issue is going to at wide open throttle when it's trying to get in as much air as it can. If you can't get in enough oxygen to turn those hydrocarbons into CO2 and water vapor, that's going to be the limitation as to how much power can be extracted.

An internal combustion engine is just a big air pump. Injecting more or less fuel is easy. But getting in more oxygen into an engine gasping for breath is hard. There have been all sorts of things to improve the amount of air that can be pumped. Bigger intakes. Less restrictive exhausts. Multiple valves to improve airflow. Forced induction. Nitrous injection. As was stated, using oxygenated fuel is just giving it a little bit more oxygen when it can't really suck in any more.

But at normal cruising speeds or when commuting, the higher energy density is probably more desirable. But for performance driving, oxygenated fuel will be better. I believe there are other things about oxygenated fuel that helps with performance - something about more efficient cooling.

 

[OppositeLocK]

No. The fuel's energy density is not the hard part. If there's less energy density in the fuel, it's still a liquid and it's easy to just inject more if more is needed. For example, pure alcohol engines (think IndyCar) can be really powerful even running methanol with considerably less energy density than gasoline. But I believe the big issue is going to at wide open throttle when it's trying to get in as much air as it can. If you can't get in enough oxygen to turn those hydrocarbons into CO2 and water vapor, that's going to be the limitation as to how much power can be extracted.

An internal combustion engine is just a big air pump. Injecting more or less fuel is easy. But getting in more oxygen into an engine gasping for breath is hard. There have been all sorts of things to improve the amount of air that can be pumped. Bigger intakes. Less restrictive exhausts. Multiple valves to improve airflow. Forced induction. Nitrous injection. As was stated, using oxygenated fuel is just giving it a little bit more oxygen when it can't really suck in any more.

But at normal cruising speeds or when commuting, the higher energy density is probably more desirable. But for performance driving, oxygenated fuel will be better. I believe there are other things about oxygenated fuel that helps with performance - something about more efficient cooling.

Interesting. But would turbos do anything to compensate for that? Such as just increasing compression?

 

[y_p_w]

Interesting. But would turbos do anything to compensate for that? Such as just increasing compression?

my 2004 WRX engine has a relatively low 8:1 compression ratio. The boost is supposed to compensate for that. But then it has all that stuff to try and suck more air including the turbo, VVT, an intercooler, etc. Compensating for lower energy density of the fuel is easy. Eventually it”s going to max out on how much oxygen is available, and the ECU adjusts. The oxygen in the fuel in addition to everything else.

 

[y_p_w]

But doesn't denser mean more energy? So with more energy per volume, a potential bigger bang with each revolution?

Again - I'm no expert on this, but the key is that you're talking about energy per unit volume of **liquid**. That liquid is then turned into a mist that doesn't fill the cylinder. When you're driving around town with a fuel injected engine, the accelerator affects the amount of air coming in (via the throttle body), and then the amount of fuel injected is adjusted to reflect that. And it's really easy to just inject more fuel. You were looking at it the other way (adjusting air to match the amount of fuel) which is not how it works.

When you're flooring the accelerator and it's up to maximum air flow, it's still at the level where there should be no problem just injecting enough fuel to match the amount of oxygen in the cylinder.

If energy density of liquid fuel were the key to everything, then diesel or kerosene would be more powerful.

 

[Surestick]

Unless your engine is GDI then the fuel is injected somewhere upstream of the intake valve.
The additional fuel displaces air in the intake which means you are limiting power slightly. It's doubtful you would be able to tell the difference between E0 and E10.
The difference in energy density means that you need a bit more of a less energy dense fuel to obtain a given power so your mpg will drop.

 

[y_p_w]

Unless your engine is GDI then the fuel is injected somewhere upstream of the intake valve.
The additional fuel displaces air in the intake which means you are limiting power slightly. It's doubtful you would be able to tell the difference between E0 and E10.
The difference in energy density means that you need a bit more of a less energy dense fuel to obtain a given power so your mpg will drop.

Fuel economy certainly, since fuel economy at cruising speeds is heavily dependent on energy content unless the engine can advance timing to take advantage of higher octane - especially flex fuel engines.

But displacing air will not mean less power if there’s an oxygenate. If that really reduced power, then nitrous injection wouldn’t boost power. There's also a power benefit in cooling the mixture. All in all, oxygenated fuel has the potential to produce more power even with a lower energy density.

 

[Kernel Potter]

But displacing air will not mean less power if there’s an oxygenate. If that really reduced power, then nitrous injection wouldn’t boost power. There's also a power benefit in cooling the mixture. All in all, oxygenated fuel has the potential to produce more power even with a lower energy density.

Good point y_p_w. When I come across people that don't comprehend this I'll throw out the most extreme example that I know of that undeniably hammers the point home.

I give the example of a 4 cylinder engine from nearly 50 years ago that was about 160 cubic inches and ultimately made 1,000 horse power. Not only was it reliable but it won major races. To make this power it had a turbocharger delivering over 40 pounds of boost. But it did NOT have an intercooler. The races it won were a lot the Indianapolis 500s - plus scores of others. It was able to do this for a lot a reasons but the biggest reason was it ran 100% methanol for its fuel.

It also helps that it was amoung the very best racing engines ever made. Many would argue that it was the very best. The engine was the Offenhauser originally designed as a boat engine by Harry Miller. For anyone familiar with Harry Miller that explains a lot. Fred Offenhuaser and Leo Goosen explain most of the rest.

But the bottom line is the cooling effect and the effective octane of 100% methanol made all that horsepower and reliability possible.

 

[wpod]

I ran alcohol free gas for a couple on months in my 2015 2.7 Eco boost F150 and A consistently get 23.5 with up to 10% pump gas doing the math and 1 mpg better running alcohol free gas.

 

[y_p_w]

Good point y_p_w. When I come across people that don't comprehend this I'll throw out the most extreme example that I know of that undeniably hammers the point home.

I give the example of a 4 cylinder engine from nearly 50 years ago that was about 160 cubic inches and ultimately made 1,000 horse power. Not only was it reliable but it won major races. To make this power it had a turbocharger delivering over 40 pounds of boost. But it did NOT have an intercooler. The races it won were a lot the Indianapolis 500s - plus scores of others. It was able to do this for a lot a reasons but the biggest reason was it ran 100% methanol for its fuel.

It also helps that it was amoung the very best racing engines ever made. Many would argue that it was the very best. The engine was the Offenhauser originally designed as a boat engine by Harry Miller. For anyone familiar with Harry Miller that explains a lot. Fred Offenhuaser and Leo Goosen explain most of the rest.

But the bottom line is the cooling effect and the effective octane of 100% methanol made all that horsepower and reliability possible.

I thought about mentioning pure alcohol engines like in Indy Car, but that might not have been a fair comparison because of the effective octane rating being so much higher. I was getting at the claim that (assuming all things being equal such as octane rating) displacing air with ethanol would decrease power. I’m pretty sure it’s slightly more because the amount of oxygen added in the fuel is more than that what’s displaced. And all ICE engines are just air pumps where it’s really about matching the fuel to the amount of oxygen.

 

[Dorian]

In my 99 Camry 5S-FE the car ran better with E0 91, though no increase in power. Mileage average went from 27 mpg to 31. The engine felt more refined as far as NVH and idle quality. Though, the $0.65/gallon increase was not worth it.
The Hybrid actually had no increase in mileage and no noticeable power or NVH change. The 14.5 actually ran great with it and felt a little more torquey, with about a 2 mpg increase. Top Tier regular still is the way to go considering cost.

 

[SwampSurvivor]

Years ago, when they got their 2012 Escape 2.0 GTDI, my father did some long term calculations on running 91 Ethanol free vs standard 87 e10.

The fuel economy increase from running 91 ethanol free paid for the higher cost of the fuel. By a large margin? No. Like pennies per thousands of miles. At that point, it's worth it to not be running ethanol fuel.

I use regular E10 in daily drivers. Stuff that sits get E0 along with anything that has a carburetor. I don't like stabil. I've seen that create sludge in the tank.

 

[Tom NJ]

Does the car computer make any adjustments when switching from E10 to E0? If so, how fast does this occur?

 

[Hermann]

The only close by E0 is a 91 octane. It is not Top Tier, It is 50¢ more than E10 87 octane TT. Have noticed that my new motorcycle does not like E0. As far as mileage, noticed no difference.

 

[loneryder]

I saw ethanol-free gas for the first time when I went on a trip to Bar Harbor recently. The closest gas station that offers it is 30 minutes away from anywhere I go, but I think it's worth it.

Before I started using it, I always averaged
25-26 mpg and getting about 370 miles a tank during summer.

Now after my second tank of ethanol free gas, in mostly rural driving with the AC always running, I'm getting 27.8 mpg and got 420 miles before the gas light even came on. The butt-dyno says there's a slight increase in torque, but that's not always accurate.

Anyway, is ethanol free a wise choice for a GDI engine? It definitely seems to drive better and is much better efficiency wise, but I'm not sure what difference there is inside the motor.

You should get 10-15% better gas mileage using ethanol free gas.

 

[y_p_w]

Does the car computer make any adjustments when switching from E10 to E0? If so, how fast does this occur?

Well - I think the two main components at play would be the O2 sensor and the knock sensor. I think even if you had a blend of E0 and E10 in the tank where it's not thoroughly blended and varying amounts of ethanol are being sprayed, it would just adjust within a split second. The engine really has no way of knowing what's in there. It can only observe what's happening with its sensors and then adjust accordingly.

I remember getting into a argument with someone who insisted that engine detonation was not something to be trifled with, and that he didn't necessarily trust that one should rely sensors to prevent destruction of the engine. But way too many cars these days rely on their electronics to produce the most power and highest fuel economy without risk of the engine destroying itself.

 

[madeej11]

You should get 10-15% better gas mileage using ethanol free gas.

That sounds way out of wack. I would say 3-5%.