10% ethanol
 

how do you guys feel about the ethanol content in our fuel? wouldn't that raise the octane slightly? I'm not 100% sure how all this stuff works, but a dude at work brought it up yesterday.

I had the same concerns a while back when I first saw the stickers on the pump.
Seems like the ethanol will increase performance slightly, but reduce the fuel economy.
I'll look for the thread in the other forum.

so basically the ethanol (which is probably added so that we're "less dependent on foreign oil") is doing absolutely nothing for our dependence on foreign oil... nice.

Here it is:
MS3 Fuel and Ethanol...? Issues??? - Mazda Forums

this is correct, its like a race fuel, more power, about 30% worse fuel milage and almost no emissions

Is it all that beneficial in terms of performance though...? I've been trying to avoid fueling stations with it...?

i saw on the discovery channel they said ethenol fuel delivers like 30% more power,30% worse fuel economy and costs about 30% more than gasoline. has less then 10% the emissions of gasoline.

MTBE (methyl tertiary-butyl ether) has been commonly used to increase the octane rating of fuel since we stopped using lead to do this job. Because MTBE is a known carcinogen (and a very bad one) they are starting to use ethanol to raise the octane rating of the fuel.

Ethanol has 30% less energy per unit volume when compared to gasoline. This means a reduction of 30% in gas mileage. A properly designed engine could make the same amount of power or even more than a gasoline because of the ability to run higher compression ratios, but there is no getting around that there is less energy per gallon in ethanol than gasoline.

So what does this mean for us? We can run higher boost and timing?
Do our ECUs compensate/adjust for the increases detonation resistance?

If the standard fuel is 93 (here in FL), then why isn't is corrected if the ethanol increases it? Does that mean that 89 is really 91, 91 is 93, and 93 is 95????

I am not sure how a fuel could give more power but less economy. kind of a paradox.

the rating you see on the pump is the MINIMUM octane rating. 93 is really a minimum of 93 octane, meaning it's probably higher anyway. I doubt that refineries are like "hm lets take 93 octane and make it 95 with the ethanol because we just like people and want them to have better gasoline!!!" it's all about the bottom line.

i think its cuase it burns hotter and faster than gasoline it realeases it energy faster=less economy

Exactly. The 93 is the same as any other 93, except the additive is ethanol instead of, or in addition to, MTBE


I ran 93 in my motorcycle in WV, and I avoided stations with the 10% ethanol. I move to CA and all I can get is the ethanol 91, and the motorcycle instantly runs like shit. It could be alot of things, but I choose to blame the fuel.

well seeing as how you went from 93 to 91, that is one reason.

Ethanol actually burns cooler... If you see guys running straight alcohol, the motor is actually cool to the touch.

Economy is reduced because you actually burn more than equal amounts of gasoline. If you ever ran alky on a carbed setup, you know you have to significantly fatten up the jetting.

Ethanol currently cost's more to produce because the manufacturing process is very limited. In the next 5-10 years, this will change greatly, with ethanol costing less than half what gasoline now costs us. That and our money will be going to the American Farmer rather than to the middle east.

There are several guys down here in dallas running 100% ethanol on 700+hp cars with no issues.

I think I am not incorrect in assuming that economy and power are both dependent on the amount of energy released when fuel is burned. someone feel like chiming in here?

good, lets give all of our money to the corn farmers. I mean corn was already in EVERYTHING at the grocery store, lets put it in our fuel too. yayyyyyy.:banghead2:

I sense some sarcasm...

Truth is, the American farmer is only staying alive from government subsidiaries. There is no longer any money in farming and most small farmers have been replaced by large corporations...

The move to Ethanol could greatly help the small farmer into actually profiting from his crops. Money that stays in the U.S. is always a good thing!

ziggo said "ethonal has 30% less engery per unit than gasoline" ethenal has a higher octane raeting so more power BUT it has 30% less "storage" capacity of energy than gas ..thus more power and worse economy.

octane doesn't have anything to do with power, it has to do with the speed of the burn. higher octane fuels are more stable, and thus slower burning, which is why you can run advanced timing with them.

30% less energy per unit means that it releases 30% less energy when burned... that means less power to me. anyone else?

I'll find out and give you an explanation. but you are incorrect in sayin less power, ethanol increases horsepower while at the same time reduceing economy.

your rite about the octane the higher the slower the release of the stored energy.. but achohal stores less energy and burns faster, does it give more power than gas???

Here ya go!

good article! so in conclusion.... ethenal alcohal delevers more horsepower while at the same time delivering worse economy.

Ethanol's burn rate is 2:1 over gasoline.

that doesn't answer anything though.... other than we'd probably need more energy to start the car and run it until the engine reaches operating temperature...

so in conclusion, we'll have an even rougher cold start idle problem than we already do...

I don't know how you could possibly conclude that. it's all about energy release. you only get more power if you advance the timing enough to compensate for the slower burn.

so it burns faster? what am I missing here?

BAD!!! come back..lol

this means less emissions

this means less power because some of it is being used to vaporise the fuel


what am I missing

Exactly, it burns quicker. Hence why you fuel economy is going down roughly 3-5 mpg.

I get why economy is decreasing. what I don't understand is how (at the same time) power could increase. to me, that is totally counterintuitive.

Alcohol's base octane rating is 130 octane. When added to gasoline, it makes the fuel a tad bit cooler, which the car can make a tad bit more power.

oh no, I'm lost again.


would a cooler engine be more or less efficient?

is all of this just theory or are there dynos of gasohol vs gas? if it's theory, I'll just write it off as poop, but if I can see dyno and efficiency proof of it, I might buy into it.

i'm trying to find it but i have read about it in popular mechanics where they showed ethenol made more hp than gasoline but with dismal fuel economy, aslo they called it a "race fuel" on speed tv, Also the race car "Koieing" built a 1000hp ethenol car and i remeber reading how the article said it made the power esier cuase of the ehtonal.

Theres plenty of data out there if you're willing to search it on google. If alcohol didn't have this amazing power/cooling ability, why would turbo cars benefit from Methanol Injection?

Ethanol is cheap to manufacture and is used instead of MTBE to keep everyone happy. It also burns cleaner.. hence.. the power of alcohol.

I'm having issues understand this less fuel economy and more power concept...

But I think that what they are trying to say is that ethanol has potential to make more power if you tune for it...its not going to make more power just by putting it in your tank...

Is this right?

I only did a cursory search so I guess I'll have to research it further. I did read that it costs more energy to produce than it provides though. that doesn't sound like cheap energy to me.

that has to be the only way that it's true. an explosion is an explosion. it's just a force over a period of time. the only thing we're worried about is the amount of force and the amount of time. if you increase either it's going to make more power and economy. if you decrease either, it's going to make less of both.

also, how many of those people do you hear getting more power but less miles per gallon?

This explains it better:


Hense more power, more consumption.... with less dependence on atmospheric air due to quench = 5:1-6:1

EVERYONE?????

Seriously, those go hand in hand!!

I don't think anyone in quest of "more power" is going to comment or worry about fuel economy... :rotf:

what about "efficiency" horsepower?

ie putting a more efficient intake on so that power is not wasted drawing air into the engine, or putting an exhaust system on so that power is not wasted pushing exhaust gases out? there is plenty of stuff you can do to make more power and more economy.

I see tons of people commenting and worrying about fuel economy. shall I search threads?;)

The simple fact is, horsepower is made by more efficiently being able to add more fuel and more air.... simple as that. You can't make more power with less of either even in the most optimum environments.

:no: :rolleyes:


:D

the efficiency gains come from converting parts from restrictive oem parts to more "optomized" aftermarket parts. do you think your car came from the factory with the "optimum environment" for making perfectly efficient horsepower? no, they wanted it to be quieter, and nicer to drive than an F1 car.

I'm just sayin.

when I had my 350z stock I got like 25 mpg ont he highway. after I put my intake, plenum, and exhaust on it, I was getting over 30. granted, at WOT, I'm sure that my economy was worse than stock, but cruising, the system was much more efficient. do you think the EPA is computing mileage at WOT or cruising speeds?

Direct Injection more efficiently adds fuel to the combustion chamber by atomization.

Turbo's assist in forcing more atmospheric air into the cylinder so that more fuel can be added as well for more power

NO2 changes the atmospheric air properties so that the air is denser so that more fuel can be added, or added in conjunction.

If you want more power, you must have more fuel, simple as that. All the bolt on crap just assists in making the delivery more efficient. Once the optimum efficiency is hit, there is nothing else but more fuel and air.

Ethynol does not burn correctly in gasoline engines. It, like most other alcohol fuels need a compression ratio over 11.5:1 just to combust. My uncle's been running Hartog Oil for years, and according to him, ethynol is added to gasoline simply as a filler. That's why it's up to the particular station. It makes that 35,000 gallon tank underground "up to 10%" cheaper for them to fill back up, even though most of them don't pass on their savings to their customers. Then you get worse gas mileage and have to come back sooner.

While we're on the subject of gas/gas stations; did you know there's a return line at the handle of the hose that is there to return "fumes" back to the storage tank? When you click the hose to spray the fastest, fumes and spatter get returned through that. Too bad the flow sensor is before that, so you end up paying for a bit of fuel that ends up getting returned. Also, never fill up right after a station refills it's storage tank. When the refill, alot of crap that's settled to the bottom over the last few weeks gets stirred up. I wouldn't want to run that shit through my motor. Takes about a day and a half for it to settle back down. Just some fyi.

ok you've just said exactly what I did. congrats. we're now on the same page.

I'll set up survailance cameras at my gas station to see exactly when the trucks drop the new load in there.

lets get back on topic, shall we?

bottom line:
1. we're using the SAME amount of fuel and air
2. the fuel is slightly different

how is it possible that, given the same amount of fuel and air are going into the combustion chamber and no tuning has been performed, an engine can have more power and less economy?

You can ask the guy inside what their refill schedule is. It's usually consistant (every other wednesay, every 20 days, ect...).

yeah you beat me to it...... I understand what you're saying, it's just typically if you want allot more power.... you're finding ways to get more fuel and air in the system....

Making power is counter to efficiency... otherwise we would all have 1000HP, 100mpg cars....

to me it is fairly straight forward that if the new fuel creates more energy when burned, economy and power will go up. if it creates less energy when burned, both will go down.

we aren't talking about MORE fuel here though, we're talking about DIFFERENT fuel.

Agreed, but since Ethanol burns at 5-6:1 instead of 13-14:1.... efficiency is directly related.... and hence our side argument on more power=larger consumption of fuel.

to consume more fuel, you'd have to either be on the gas more, or have a different tune though. what am I not getting here?

Well you don't make horsepower at idle.....

ok here is what I am not getting:

more power = more horsepower at WOT. this is straight forward. it means that when you add ethanol to gasoline, you get a more explosive burn, releasing more energy and pushing the piston down harder for each power stroke.

less efficiency = more fuel needed to cruise. if each explosion is pushing the piston down harder on each power stroke, then you shouldn't need the same volume of fuel to create the amount of power needed to make your car go, say 55 mph. that means you're using LESS fuel to make it go 55 mph. that means you're actually running MORE efficiently.

But you are comparing two different fuel sources...

OH MY GOD

I want to ban you from my thread.

different fuel sources don't matter. the physics are the same dude. do you think that just because this other stuff is made from corn that it's magical and not subject to the laws of physics?

LOL!!!

Okay.... each explosion with ethanol does create a higher level of energy = more power.

But, since ethanol's squelch is at 6:1 instead of 14:1, it takes twice as much ethanol for each explosion as would gasoline.... so you get poorer gas mileage.


As compared to running 100% gasoline....

ok so what is making your car pump more fuel into the combustion chamber? to get worse gas mileage, you're going to have to either have a poorer burn, or tell your car to pump more fuel. there are two ways to pump more fuel: add more air, or change the way the computer is mixing. I don't think using 10% ethanol is changing either of these.

ut oh wheels are turning....

I wonder if, since ethanol is a "cleaner burning" fuel that the o2 sensor is not picking up the mixture as rich enough and adding more fuel to compensate.... that would mean that our cars would be running even more pig rich than normal... what do you guys think? this is the only thing that would make me believe the more power worse economy argument, and it actually makes sense... there is more fuel that the computer is seeing.... kinda. anyone?

I could find the equations later, but the thermal efficiency is directly related to the compression ratio of an engine. The fuel source matters not, its all just heat in as far as the energy is concerned. Its another reason why Diesels are more efficent than gasoline engines.

Ethanol CAN make more power in an engine if the compression ratio is raised to take advantage of it. Even if the engine is desiged for it though you are still going to have to burn more of it to get the same heat out of it due to the reduced energy content. There are numbers floating around, but running 100% Ethanol in an engine designed for gasoline WILL result in a gas mileage reduction of ~30%, I think running ethanol in an engine with a proper compression ratio will result in a reduction of ~5-10%. This is because while you are using more fuel to generate the heat, you are also becoming more thermally efficient. The gains in thermal efficiciency never offset the loss of energy per unit volume when compared to gasoline.

FYI, an engine is most "efficent" when it is running WOT at its torque peak (peak volumetric efficiency). The reason that this is not practical in real life is because it doesnt take into effect wind resistance. The faster you go the more energy you lose to drag. You can play some interesting games with CVTs, and engines that switch on and off to take advantage of this.

e-85 is hillbilly race-gas equivilent to 100+ octane. With a higher octane rating, you can run more boost and more time with better cooling and less knock. Modern cars run much hotter than necessary for emissions purposes. Alky injection not only bumps up the octane, but cools the cylinder with the water instead of fuel.

Less fuel=more power.

What we're all missing from this discussion is that the stoich for ethanol is NOT the same as gasoline. Gasoline is 14.7:1 while pure ethanol is 9:1.

That means that if you're burning pure ethanol your combustion is happening with 9 parts air and 1 part ethanol. That means that you're using more ethanol for the same amount of air than if it was pure gasoline just to have the combustion happen at stoich.

Now, if you add 10% ethanol to gas, you end up with a stoich of about 14.2 ... so if you guys using 10% ethanol-enhanced gas see your AFR's at 14.2 or so, you now know why. :D

Actually you are incorrect, i see a stoch of 14.6 or 14.7 with 10% Ethanol in my fuel at idle. Theory wise, that sounds logical... reality, it's not. Gasoline still supercedes as 90%. 10% alcohol isnt going to change a thing, except make your fuel burn quicker... which is something we are seeing here in CA and probably across the US. They ( oil companies ) are using it as a cheap filler and making even more money off conserving 10% of extra gasoline.

That's odd, because I see 14.1/14.2 with 10% ethanol and others have said the same thing that use the same Sunoco 94 gas up here.

Plus if you do the math it makes perfect sense.

I may put in 91 non-ethanol (can't get any higher on pure gas) just to see though.