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58mm of Bliss
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I see a ton of people jumping on the E85 bandwagon without understanding what benifits it really offers.

Why does E85 make more power than Gasoline?

The main answer: Auto Ignition Point

This is the temperature that a fuel will ignite at if you were to heat it up.

93 Octane Gasoline = 280 Degrees C

E85 = 365 Degress C

What this means is that you can heat up and compress an intake charge with E85 a LOT more than pump fuel before it auto-ignites. In laymans terms, this means you can run higher compression ratios and higher inlet temps; a side effect of spinning a turbo or SC out of the center of it's efficiency range.

Fuel Octane is often mistakenly quoted as the main reason why E85 is "better" than pump fuel, but the differences between the 2 is relatively minor compared to the auto ignition point.

Pump fuel = 93 Octane
E85 = Approximately 102 Octane

What does this all mean?

I means you can run a few degrees more timing resulting in up to 8% increase in power, and you can additionally run a higher compression ratio resulting in up to 3% more power.

There is also a difference in the amount of energy stored in E85 versus 93 Octane fuel:

93 Octane = 35 Mjoules / Liter
E85 = 25 Mjoules / Liter

This really throws people for a loop initially, as the above basically means that 93 Octane fuel has approximately 40% more energy in it.

But....when you look at the stoich values for the two fuels, the picture becomes a little clearer:

93 Octane = 14.7:1
E85 = 9.79:1

At Stoich mixture preparation, E85 uses 50% more fuel than 93 Octane.


At the other end of the spectrum is Nitromethane. I bet most people didn't know it has an octane value of 60, and is stoich at 3:1.
 

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I checked the material safety data sheet at the servo the other day and it says 105-106 octane depending on mix.

I drive on E85 every day, have done for 30,000km's and the difference in fuel consumption is only 10%
 

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well I recently switched over to e85, without touching the timing (which it definately needs more) my butt dyno feels a dramatic difference. and feels a lot smoother.

I don't know how factual this is so feel free to correct me, but a couple of other benefits

increased cooling of intake charge due to more fuel being injected and alcohol evaporates quicker

I thought fuel for fuel at stioch that e85 has about 11% more energy (could probably figure it out based on the values you provided)

on a side note does anyone have any documentation on what the other 15% of e85 is? 87 octane gas? less/more? is it even gas? I heard somewhere that by law it doesn't even have to be gas... scary.:yikes:
 

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Also seen 200 degree celcius exhaust temp drop on an Evo 8 track car with E85
 

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What this means is that you can heat up and compress an intake charge with E85 a LOT more than pump fuel before it auto-ignites. In laymans terms, this means you can run higher compression ratios and higher inlet temps.

What does this all mean?

I means you can run a few degrees more timing
In fairness, this is basically the definition of octane, regardless of what the number assigned to it is.
 

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Very cool. How does long term E85 use make your valves and combustion chamber? Sparkly clean? Much better than gasoline?

I see 105 octane thrown around the most. How is it that it takes 110 octane race gas to make the same power? Is it the timing difference?

I saw this crop up a few places. Is it totally bunk? It claims that all the octane reading are totally wrong and E95 is between 94-96 octane. That makes no sense what so ever. but it did show up in a reasonably well regarded publication, the "Changes in Gasoline IV, sponsored by Renewable Fuels Foundation"

http://ethanolrfa.3cdn.net/dd9e74ce1c454a97cc_rbm6bdgh3.pdf


Octane: A minimum octane for E85 is not specified. FFV's
can tolerate the lower octane of gasoline i.e. 87 (R+M)/2.
There is no requirement to post octane on an E85 dispenser.
If a retailer chooses to post octane, they should be aware that
the often cited 105 octane is incorrect. This number was
derived by using ethanol's blending octane value in gasoline.
This is not the proper way to calculate the octane of E85.
Ethanol's true octane value should be used to calculate E85's
octane value. This results in an octane range of 94-96 (R+M)/
2. These calculations have been confirmed by actual octane
engine tests.


Oh, never mind. I found a 13 page post here on this specific statement:

http://forum.e46fanatics.com/showthread.php?t=887857

Estoril says "There's multiple ways of calculating octane. We are one of the only countries to use the rating you just cited.

Fact is, the results speak for themselves. You will make as much power or more out of e85 safely then race gas. That's all you need to know.
Whether or not it's "worth it" is personal opinion weighing the pros and cons. For me it was a no brainer as I speced my fuel system to be compatible (really you have to try not to) and with enough volume to support it to start with. If it's going to cost you a few thousand to be able to do it, then you have to ask yourself if it's worth it to get race gas performance for pump gas prices, for me it would still be a no brainer"
I agree 100% with Estoril

http://forum.e46fanatics.com/showthread.php?t=887857

In the above thread Sound Performance claims E85 outperforms C16 race gas. Fact? Or fiction? check this:
http://www.modularfords.com/f17/e85-vs-c16-dyno-results-165771/index6.html
 

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The 2 liter turbo (LNF - direct injected motor from a Cobalt SS) in my solo/autox mod car uses E85 and it runs 20 degrees cooler for water temp's and generates 45 more rwhp than 93 octane. Of course, 40% bigger injectors are needed along with a remap of the ECU. For race cars it is the way to go - NASCAR likes it.

Jim
 

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Can you speak to E85 being corrosive, is this true?
Listen dumb ass, if you don't know what hygroscopicity means, you have no business tuning cars.

Anyone who thinks they can ignore the hygroscopic nature of alcohol, and treat it like any other hydrocarbon based fuel is in for a big surprise.

Start reading.

http://www.injectordynamics.com/AlcoholArticle.html

Short answer, yes.

Long answer, sortof. E85 is very hygroscopic, it takes in and holds moisture in the atmosphere that it is exposed to. Therefore, two things happen:

-The iron in fuel injectors is exposed to water within the e85, and corrodes

-Rubber fuel lines and other fittings are dried out by the E85. Therefore special fuel system upgrades are usually a large component of a gasoline to E85 swap.

(PEI correct me If I got something wrong. :thumbup:)

EDIT: Also, :eeps:
 

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Listen dumb ass, if you don't know what hygroscopicity means, you have no business tuning cars.

Anyone who thinks they can ignore the hygroscopic nature of alcohol, and treat it like any other hydrocarbon based fuel is in for a big surprise.

Start reading.

http://www.injectordynamics.com/AlcoholArticle.html

Short answer, yes.

Long answer, sortof. E85 is very hygroscopic, it takes in and holds moisture in the atmosphere that it is exposed to. Therefore, two things happen:

-The iron in fuel injectors is exposed to water within the e85, and corrodes

-Rubber fuel lines and other fittings are dried out by the E85. Therefore special fuel system upgrades are usually a large component of a gasoline to E85 swap.

(PEI correct me If I got something wrong. :thumbup:)

EDIT: Also, :eeps:

I think (hope) Andy was just trying to be funny by quoting this:


QUOTE FROM: http://www.injectordynamics.com/AlcoholArticle.html

"And now that you know a cool new word, you can use it to ***** slap unsuspecting goofs on the internet.

Example:

"Listen dumb ass, if you don't know what hygroscopicity means, you have no business tuning cars"

Or..."Anyone who thinks they can ignore the hygroscopic nature of alcohol, and treat it like any other hydrocarbon based fuel is in for a big surprise"

With intelligent witty posts like that, no one will ever guess that you are a forty year old virgin living in your mom's basement."


Rob
 
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