Blend E85 with gasoline to increase octane?

[GT Mike]

Would this work? There's a couple stations that sell E85 fuel and it's about 20 cents a gallon cheaper than 87, and rated at 105 octane. If I blended a few gallons into 91 octane gasoline that already contains 10% ethanol, would it hurt anything?
I can't see it being all that harmful really, other than maybe screwing up the fuel trims from the added oxygen content of the fuel.

Any idea on what the mix ratio would have to be to achieve and end batch octane of ~94-95?

Any thoughts are welcome.

I've thought about trying some straight up in my 17HP Ariens garden tractor too...It would be simple since I can manually adjust fuel mixture and ignition timing to be optimum for it.
Anything to get that stinky thing to clean up a little is worthwhile as far as I'm concerned. The exhaust smell is just nauseating on anything but race gas (smells like the dragstrip then), and that gets a little pricey to mow the grass with.

 

[hannaco]

Try 2 gallons of E85 to 7 gallons of 91 octane.

 

[T-Keith]

If your looking to use in a performance application I would not. Ethanol has a lower caloric value, that means less power, less fuel economy. It's bad for small engines too, because it gums up carborators very well.

-T

 

[rpn453]

I wouldn't go over 10% ethanol on a normal car unless the manufacturer specifies that it's OK.
As T-Keith said, you'll get less power and higher fuel consumption with increased ethanol content.
So why the extra octane? Is it for a drag car?

 

[GT Mike]

My car is already octane hungry. It gets knock retard on anything but the best 93 I can feed it.

It runs satisfactorily on the lesser octanes, but the PCM learns the amount of knock it's seeing and runs on a less agressive advance curve at WOT.

I was just curious if anyone has ever run a non-flex fuel vehicle on straight E85 or a blend more than the standard 10%.

 

[SteveD2]

Use race gas. As others have said, the only thing alcohol is good for is the environment. It is a TERRIBLE thing for engines.

 

[wwillson]

quote:

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Originally posted by ZmOz:
Use race gas. As others have said, the only thing alcohol is good for is the environment. It is a TERRIBLE thing for engines.

---

"Terrible thing for engines"

Prove it...

 

[XS650]

quote:

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Originally posted by ZmOz:
Use race gas. As others have said, the only thing alcohol is good for is the environment. It is a TERRIBLE thing for engines.

---

The wine I am drinking tonight is about 11% ethanol. It's doing some good, but not necessarily for the environment.

 

[Jackpot01]

I have had the best luck with 94 Sunoco in my Maxima. I havent had any knock in the car, but it does run the best on that.

Eric

 

[tweeker43]

high alcohol fuels (e85) should only be run in vehicles with "flex-fuel" fuel systems. alcohol can cause problems in systems not intended for that use.

i would at least calculate your finished percentage before adding this.

for instance, if you had a 16 gallon tank:

(12 gal * .10 + 4 gal * .85) / 16 gal = 28.75% alcohol.

this would be a bit high for my taste. flex fuel systems have different materials (like stainless steel and special plastics) that are designed to withstand the corrosive nature of the alcohol.

 

[JeepZJ4.0]

quote:

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Originally posted by GT Mike:
My car is already octane hungry. It gets knock retard on anything but the best 93 I can feed it.

It runs satisfactorily on the lesser octanes, but the PCM learns the amount of knock it's seeing and runs on a less agressive advance curve at WOT.

I was just curious if anyone has ever run a non-flex fuel vehicle on straight E85 or a blend more than the standard 10%.

---

Sounds like you need to decarbonize your cylinders with Seafoam or Deep Creep or something else with the same effect.

 

[GT Mike]

Very difficult to do with the design of the 3800's upper plenum. Most the cleaner ends up sitting in puddles on the floor of the lower intake manifold, since the intake runners are at the top of the barrel shaped plenum. Some of these engines (mine included) just like a lot of octane, others don't.

I've tried GM Top Engine Cleaner in it, but again, about only 20% of the cleaner actually made it into the cylinders.

I really don't think it's a carbon issue either...I'm leaning to believe that it just is running too lean for the amount of compression and advance to run on anything but premium without measureable knock.

You Jeepers don't have to worry about knock sensors on the 4.0L engines. When they ping, you hear it. Believe me, I know about that. I've owned 3 Jeeps before buying my GP, 2 of which had the 4.0L.
We just get doggy engines that have to be scanned to figure out why.