A real look at E-85

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Joined
Jun 16, 2013
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Location
Iowa
My Car
1973 Mustang Mach 1
I am going to give you all some data on E-85 verses using Premium gasoline. This will be geared to being pro E-85, please READ THE ENTIRE POST before screaming NO at the top of your lungs. I am aware Ethanol has negative effects on hoses, gaskets, and has a possibility of corrosion on our original equipment. This will be viewed in terms of analysis, of ACTUAL fuel specifications, NOT how much it would cost to retrofit or continued maintenance. That being said:

E-85 has about 73-83% of the BTU content of straight Gasoline.

E-85 get around a 25% reduction mileage per gallon.

E-85 has 100-105 octane rating compared to 91-94 for premium.

Stoichiometry A/F Ratio: E-100 is 9:1, Gasoline is 14.6:1 E-85 should be approximately 9.84:1 (based on ratios)

In Ames, IA as of 5/24/2017: E-85 has a cost of $1.799, Premium (93) has a cost of $2.899.

Analysis:

You can purchase approximately 1.61 gallons of E-85 for the same price as a gallon of (93) Premium.

With a 25% mileage reduction- 1.61 gallons would actually equal 1.21 gallons for equal distance of travel for Premium. This means you would be able to move 21% further for the same money at the pump.

With naturally aspirated engines at 14.6:1 burn ration E-85 to burn would only require 67% to burn an equivalent liquid volume. That means you can increase the fuel volume into the cylinder by around 33% at the same air ratio. With evaluating a BTU decrease of the lowest end of 73% compared to Premium. In the same cylinder during combustion you could actual produce a 6% increase of BTU's over Premium fuel.

Now to examine safe compression ratios. Most agreed upon limits for TRUE E-85 would be around 16:1 compression without detonation (I realize this ignores all design differences and real world issues). Premium (93) would be around 12:1.

Boosting applications: My 351C has a compression ratio of around 9.5:1 ignoring ALOT of variables. I would be able to supercharge or turbocharge my engine safely on Premium by 4 PSI. On E-85 I would be able to pump in 10 PSI of pressure. Generally for every 15 PSI of boost you add you about double your current engines potential. As an example is my engine produces around 435 naturally aspirated. Premium @ 4 (12.1) = 553.40 E-85 @ 10 (16:1) = 731.00. (Yes I know these are theoretical calculations)

Summary:

E-85 at current cost will boost mileage by 21% compared to Premium. E-85 will allow you to increase compression ratios by internal or boosting applications. You would receive a slight increase of BTU potential in the same static environment.

  :chin:

I feel as a community we tend to look at something new and hack it off because how it was before was "better" or "just as good". Also I have noticed if you need to do anything out of "normal" maintenance every few decades its a problem.

***All of these benefits from getting some difference fuel lines (rubber and metal), carburetor (or EFI retune), and replacing a fuel take and sending unit periodically. With as low of gas mileage as we get a 21% boost would pay for itself.***

Love to hear some thoughts.

 
If Ethanol is that great take away all the government subsidies, price it as any other commodity, turn it loose in the automotive fuel market and let the consumer decide.

IOW - if it's as great as E-proponents say they shouldn't need the government forcing us to buy it be it at 10%, 15% or 85%.

 
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I don't personally believe it should be subsidized, the problem is it is. Also a small number of vintage cars buying it or vetoing it won't make it go away. The point of this was to actually discuss the fuel itself, and examine E-85's use and properties. If production costs dropped and gasoline prices increased significantly (and all subsidies magically removed) most non automotive people would not care about anything in this post and simply chose the cheapest option their car could run. That means E-85 or any kind of junk fuel that is acceptable. Also, most people who aren't considered "tuners" or "import enthusiast" will not give E-85 a chance. If it is already there and we can benefit from thinking outside the box, lets not just roast it for no reason.

 
Good points,Bob.

Most of us don't put a lot of miles on our cars, meaning the fuel saving per year would be minimal, certainly not enough to pay for periodic replacement of fuel tank, fuel pickup/sending unit, fuel pump, and fuel lines, not to mention rebuilding or replacing carburetors. Because we don't drive our cars much, we wouldn't be cycling fresh ethanal through the system often enough to keep the moisture in the ethanol from reaching corrosive levels. Ethanol is hydrophilic, meaning it attracts and absorbs water, which creates a perfect medium for growing a particular type of bacteria whose by-product is acetic acid. A daily driver likely runs through enough fuel to keep the moisture and bacteria flushed out of the fuel system. Just leaving a tank full of E-10 or E-15 sitting in our cars for a few weeks will start the corrosion process, imagine how much more acetic acid E-85 will produce.

That is why most of us try to find only ethanol-free gasoline. If we have to use ethanol-laced gasoline fuel stabilizer becomes mandatory, quickly wiping out any fuel cost savings. And, stabilizers don't completely eliminate the problem.

 
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Good points,Bob.

Most of us don't put a lot of miles on our cars, meaning the fuel saving per year would be minimal, certainly not enough to pay for periodic replacement of fuel tank, fuel pickup/sending unit, fuel pump, and fuel lines, not to mention rebuilding or replacing carburetors. Because we don't drive our cars much, we wouldn't be cycling fresh ethanal through the system often enough to keep the moisture in the ethanol from reaching corrosive levels. Ethanol is hydrophilic, meaning it attracts and absorbs water, which creates a perfect medium for growing a particular type of bacteria whose by-product is acetic acid. A daily driver likely runs through enough fuel to keep the moisture and bacteria flushed out of the fuel system. Just leaving a tank full of E-10 or E-15 sitting in our cars for a few weeks will start the corrosion process, imagine how much more acetic acid E-85 will produce.

That is why most of us try to find only ethanol-free gasoline. If we have to use ethanol-laced gasoline fuel stabilizer becomes mandatory, quickly wiping out any fuel cost savings. And, stabilizers don't completely eliminate the problem.
So even when using a carb built for E-85 it will need to constantly be rebuilt? If this is a problem for all cars? Is acetic acid bad for internal components?

Also, E-85 is like 170 proof... How can bacteria grow in that medium, but not standard drinking (hard liquor) alcohol?

 
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A daily driver will likely keep the bacteria and acetic acid flushed out, due to frequent re-fueling.

Yes, acetic acid is a problem for our cars, it is corrosive.

I know that the last time I rebuilt my Holley the kit didn't say anything about being ethanol safe, I just looked up a couple of Edelbrock kits, and they didn't say ethanol safe, and I don't remember ever seeing an ethanol fuel pump for our cars. I believe that FiTech EFI is just good for up to E-15.

 
A daily driver will likely keep the bacteria and acetic acid flushed out, due to frequent re-fueling.

Yes, acetic acid is a problem for our cars, it is corrosive.

I know that the last time I rebuilt my Holley the kit didn't say anything about being ethanol safe, I just looked up a couple of Edelbrock kits, and they didn't say ethanol safe, and I don't remember ever seeing an ethanol fuel pump for our cars. I believe that FiTech EFI is just good for up to E-15.
Okay, a follow up would be: are you sure the bacteria can survive in such high proof environment? Bacteria can grow in beer, maybe even wine on occasion, but hard liquor? Generally that stuff is so strong bacteria cannot grow in it. Do you know what makes ethanol able to be survived at such a high (170) proof level? I know that lower levels could bacteria could possibly tolerate it and produce such acid, and combined with its solvent problems it could compound a negative experience. But can they really survive at that level? Maybe that would eliminate half the problem associated with it.

 
Its a pretty horrible experience having a rowdy aspirated streeter on e85 as a daily driver. It is a lot more corrosive than you would think. Kills paint. In really tuff applications you are using near methanol volumes of fuel,the payoff is great torque 14:1 comp and or cool running engines blown or otherwise on the street.

 
The problem is the moisture the ethanol absorbs. When manufactured it has a very low moisture content. When exposed to the atmosphere it begins to absorb moisture. The longer it sets the more it absorbs. A closed fuel system will help. Most carburetors are vented to the atmosphere. Most of our carburetors were built to withstand the type of corrosion from gasoline, which is different than ethanol. Ethanol melts substances that gasoline doesn't, and vice versa. Yes, materials can be developed that withstand the corrosive effects of both.

Not only that, I like corn flakes and corn-fed beef, the price of everything associated with corn production has escalated. Burn less ethanol, not more. :whistling:

 
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Prior to moving back to TX I lived in NH. Up there they did not have E-10. They used MTBE as an additive.

When I moved here I had no first hand knowledge of E-gas but had gotten so much ethanol saves the planet sunshine blown up my butt that I thought it was a good thing and never thought twice about putting e-10 in my '69. The car went about 1 mile on E-10 before I parked it.

With moving, ramping up the business and a bad PB booster she sat for about 7 months.

After changing the booster the car would not start - not getting any fuel.

Traced it back to the fuel pump. Replaced it, car started, ran like crap. Took the old pump apart and the rubber components were swelled up and more gelatin than rubber. E-10 with Stabil ate my Holley fuel pump.

Thoroughly disgusted with how crappy the car was running it sat for another 3 months before the o-ring on the gas tank started dripping.

Drained the tank, the fuel that came out stunk to high heaven. Pulled the sending unit, the o-ring is the same jelly the pump internals were.

While it was out I decided to put my newly rebuilt low fuel sending unit in.

Again, life and business got in the way. The car sat with no fuel (other than what avoided the drain plug) for about 2 years.

Last February I started getting serious about getting the car back in shape for cruises and shows. I fixed a bunch of little things and since there is no way to avoid E-gas on road trips I replaced all the rubber fuel lines with 'green' e-safe hose and replaced the Holley street avenger with a Summit carb.

Not wanting to have the E woes again I filled it with only E-free gas (about .30 more per gallon than e-10, so $6 a tank).

Car ran great. For about 100 miles.

Fuel filter completely clogged, crap coming out of tank.

Drained the tank and ran a camera in. Sending unit looked like it spent the last 3 years in the ocean - filter sock completely gone and sediment in bottom of tank.

The fumes from the gallon or two of Hippie Gas that remained in the tank after draining it were so corrosive my rebuilt OEM sender and sock had disintegrated!

Hippie gas may be great for corn growers and the feel goods, but it's hell on cars not built for it.





 
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There are several of my friends running E-85 in their VERY fast street cars around here. IF an engine is built to the point it needs race gas E-85 is a great alternative. E-85 in a vehicle that doesn't require the octane is not a wise choice.

If anyone needs a carb or have a carb converted (or repaired) for E-85 check out Horsepower Innovations.

 
The extra fuel used in running an engine on E-85 has a cooling effect on the engine. If you want to run it, then every component in the fuel system and every piece of rubber in the engine would really need to be changed to make a car "compatible"

Not worth it in my mind, but E85 has its place-that place just isn't in my car.

 
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