LDB

Wow, you’ve been reading and believing way too much internet BS. Just as the very most basic of reality checks, with tens of millions of cars having used gas with ethanol for over 30 years, how can you possibly believe such a serious litany of problems could have gone unnoticed by everybody in the world except internet hype-mavens.

It is corrosive to certain types of metals, but not to any that have been used in fuel systems since the early 1990’s. It is mildly hygroscopic, but modern gas tanks exclude most air, so that is of little consequence. It can phase separate if it contains some dissolved water and then cools off, but so can “pure” gas. There is precisely and exactly the same probability of this happening with and without ethanol. The only slight difference is that if ethanol is present, somewhat more water can separate. But since you have a problem if any water separates, this is hardly a huge disadvantage. It only burns hotter in a carbureted engine where its presence leans out the mixture. In a fuel injected engine where the ECM varies A/F ratio to maintain constant stoichiometry (ie, any car built since 1990), it actually burns cooler, not that that really matters, as it’s a very small effect anyway. And stale after 3 weeks? Where in the world did that come from?

I don’t like ethanol in gas either, but it’s because it requires subsidies and does not provide the alleged environmental benefits. There’s no need to cite crazy performance risks to argue against ethanol. All you do with that kind of argument is allow ethanol supporters to attack the credibility of ethanol detractors.

mikeCsix

Question for you LDB, if ethanol burns hotter, that implies there is more btu's available to burn. Why then does gas mileage decrease using ethanol?

LDB

You’re the one who started out saying ethanol burned hotter. I said under most circumstances it burns a bit cooler, with the only exception being a carbureted engine, where it burns a bit hotter. Perhaps that’s the “hotter” that you are asking about.

Flame temperature is a complex function of not only heat release, but how much the reactants weigh, how fast they burn, whether you are doing it in an open flame or closed container, and if the latter, whether and if so, how fast, the container is expanding. The latter issue gets really messy in an engine because the “container” (ie, the cylinder) is expanding as the piston moves down.

Ethanol has lower energy content, which would tend to drive temp lower, but also needs less air, which drives it higher because there’s not as much air to heat up. But the thing that makes the biggest difference in the example I was citing (ie, ethanol burns hotter in a carbureted engine, but cooler in a fuel injected engine) is yet another factor, namely the rich/lean effect. A fuel injected engine holds constant stoichiometry, which means there is no change in rich/lean when you add ethanol. But carburetors hold fixed A/F ratio, which means if you use a lower BTU fuel like ethanol, the mixture gets leaner. Leaner burns hotter because with the extra oxygen present, the fuel burns faster. That means that even though the ultimate end temp after all the gases are well mixed and going down the exhaust pipe is lower due to the extra air that had to be heated up, the peak temp right as the burning is taking place is hotter.

CSixDude

I have proof of the corrosive nature of Ethanol gas. I have a motorcycle gas tank that formed rust on the top side of the tank from ethanol exposure. Toyota has also published reports of pitting found inside of the fuel rails on some of it's vehicles from ethanol exposure. Once it absorbs water, and it will, the entire mixture becomes corrosive. With regular gas, if water gets in it, the water will sink to the bottom of the tank.

mikeCsix

LDB, Thanks for the explanation, it does make sense.

It wasn't me that made the claim ethanol burned hotter though. I believe that claim was in the table presented as alleged facts. In 'Dude's follow up, he doesn't state the age of the vehicles exhibiting rust issues. I was going to dispute the temperature fact until I saw your post, hence the question.

My experience mirrors your claim of less energy with ethanol in FI engines, I found about a 10% reduction in mileage when compared in my LS-3 powered Corvette.

One one of the issues with motorcycles is their fuel systems are not as environmentally isolated as our modern cars. One of the methods I use to help keep moisture out of fuel systems is to keep the tank full and limit condensation to a minimum.

Thanks again LDB,

Mike

LDB

The problem with such “proof” is establishing causality. Some damage is found. Gas with ethanol was used part or most of the time. But was ethanol the cause? To determine that, you’d need a controlled experiment. Test identical vehicles (or tanks, or fuel system components) with and without ethanol and see if there’s a difference. Some such tests have been done, but none that I know of have been unbiased. Almost all support the desired conclusion of the sponsoring group. One was just finished by a “green” group, which said pure gas is clearly more corrosive than E10. The bias gets introduced by the exact way they make up the test fuels, or the conditions to which they are subjected. Tests sponsored by “greenies” tend to handle the test fuels with extra care or choose testing situations that emphasize normalcy. Tests sponsored by those opposed to ethanol tend to subject the test fuels to undue stresses or choose extreme testing situations.

While I’m not familiar with the Toyota paper you mentioned, most manufacturer studies are statistical analysis of warranty data, and a favorite saying of engineers is that there are lies, damn lies, and statistics. So about all we can say on causality with certainty is that various plastics, resins, and rubbers used in fuel system components before the early 1990’s were clearly susceptible to attack by ethanol containing fuel. On more modern cars, all you can say with confidence is that differences are not large, because if they were, all would have to acknowledge that obvious an answer. On engines other than cars (such as motorcycles, lawn mowers, etc), while the answers still aren’t clear, there is more room for questioning because their fuel tanks are not as well isolated.

As far as water absorption, as I pointed out earlier, pure gas absorbs water too. Yes, E10 will absorb more, but it’s not true to imply that water drops out of gas without any absorption while it gets massively absorbed into E10.

LDB

Sorry, I guess the common Csix portion of the names, plus my own inattention made me mix up CsixDude and MikeCsix.

On mileage difference, I think all you can attribute to ethanol itself for E10 is about a 3% mileage reduction. But there are other variables in gasoline blending that might get you up to 10% on any given batch. For example, without the extra octane of ethanol, a blender might replace that octane with aromatics, which have higher density and thus more energy per gallon. Regards, Larry

NashvilleGrandSport

My 71 Datsun 240Z has exhibited no ill effects from ethanol fuel in the 30 years and 110,000 miles I've driven it. Anecdotal... yes.

rcharrison1

Thanks to everyone's thoughts/suggestions. As mentioned in one of the responses, one of the things I wanted to do is help prevent corrosion in the tanks and fuel pump. Now that I know the fuel recircs. among both tanks, I'll go with the whole bottle and run the tanks to Reserve. I don't usually sweat such small details, but when in doubt, it's always helpful to get someone else's experience/thoughts. Thanks again to everyone. I was out of town this w/e and talking to another Vette owner. During the conversation, I found he had never visited a forum such as Corvette Forum. After telling him what a great resource it was, he was going to check it out as soon as he got back home.

Thanks again.

CSixDude

Rust was found in tank when motorocycle was less than 2 years old. E10 gas is all that has ever been used in it. Tank is kept full all the time. Rust is evident even on internal tubes inside the tank.

There is obviously no point in arguing with you. Don't believe me if you want, I don't really care, but the fact is that E10 gas becomes corrosive when it absorbs water as it holds the water in suspension.

Bruze

Did you have an equivalent motorcycle next to it at all times, the only variable being that it had non-ethanol gas?

Without that control, how can you conclude anything about the rust?

Chris J

I cant comment on how this works over time as I new the owning a vette, but I purchase ethanol fee fuel that is 91 octane. Car runs great would it be wise to put an additive in such as Techron?

FortMorganAl

From one of the secret books only a few of us were privledged to have GM secret in our glove compartments:http://www.c6registry.com/Technical/...tte_owners.pdf Page 5-5
Page 5-7

RocketDawg

Texaco also has Techron in it. In fact, I wouldn't be surprised if the Texaco and Chevron additives are identical.

Mad*Max

Does anybody know if the GM Fuel System Treatment is identical to Techron?

demon340

Bottom line for me, I use only top teir fuel, shell, BP, Costco. And add stabil marine formula about every fill up, for the .25c per dose if it does half of what it says on the label I'm happy.

Corvette_Ed

They are.

Corvette_Ed

It's not. Techron is a proprietary formula that belongs to Chevron Corp.

FortMorganAl

I don't know but I suspect Ed is correct. LDB is the gasoline expert here. All I know is I don't add anything except Top Tier and I have no issues at all with an extremely smooth running engine.

hope2

Use Techron tank before oil change just to be safe.