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Old 09-28-2004, 11:42 PM   #1
hotrod
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Default Using E-85 fuel in turbocharged cars ( WRX specifically)

Well I've been putting this off for a while until I had a good base of exprience but given the current news about oil prices, thought this would be a good time to open the discussion.

How many of you have used or considered using E-85 fuel in your WRX?
How many of you even know what E-85 is?

I have been running a high ethanol fuel blend in my WRX for over 2 years now, with no problems traceable to the fuel. The car really likes the high alcohol blend, with an obvious improvement in performance comparable to high octane so called "race fuels".

The Stock WRX ECU can handle up to approximately 33% E-85, by volume before you get a check engine light for "too lean" due to the fuel trims being pushed to the max rich settings. Add just a bit of pump premium and the CEL will clear.

I recently shifted to STi 550 injectors without any special changes in the engine management. Due to the cars larger injectors the car now prefers a higher blend. I am now running about 95% E-85, but have run the car on blends as low as about 30% E-85 without any serious problems. At lower blends the car has some surging due to the over size injectors at higher throttle settings, but can be easily driven as a daily driver if you stay out of the >60% throttle position transition to open loop.

The one problem is that currently E-85 sites are a little difficult to find, but the more of it we use the more available it will become.

The folks backing E-85 production are pushing as hard as they can to get stations to make it available, but its a slow process. They need customers to start asking station owners if they plan on carrying it to motivate stations to add a pump/tank.
There are currently dozens of FFV's out there that are designed to run on the stuff if folks can find a place to buy it. Simple way to drastically reduce oil demand as well, and put money in our economy instead of some other countries coffers.

I currently drive 20 miles each way to get to the nearest E-85 stations, but it is still a good deal as I am paying $1.59.9 / gal for the E-85, vs about $2.05.9 / gal for premium. ( some E-85 vendors charge at a premium fuel rate of about $2.00/gal)

With the added octane of the E-85 you can actually splash blend it with mid grade gasoline with out problems.

When I suspect it will be difficult to locate E-85 from the pump I just make a point of topping off the tank before it drops below 3/4 full. This keeps the ethanol blend up to a high enough level to avoid any drivability issues with my oversize injectors.


Any other adventurous souls out there playing with E-85?
I know a couple others are using alcohol fuels !

http://www.e85fuel.com/
http://www.e85fuel.com/database/search.php

Larry
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Old 09-29-2004, 01:08 AM   #2
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I am highly intrigued.. I'd love to give it a try
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Old 09-29-2004, 01:18 AM   #3
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and interestingly enough there is a station that apparantly sells this stuff only about a mile outta my way.. I go buy it at least once a week, but I didn't have a clue they sold this e85 stuff, guess I'll have to check it out.
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Old 09-29-2004, 02:27 AM   #4
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Just a note, in another forum the issue was raised that Utec users would have to be careful of mixture AFR in the Utec controlled portion of the map with E-85, as the ECU will adjust fuel trims as the closed loop, ecu controlled fuel trims would shift rich to compensate for the leaning effect of the alcohol on the AFR due to the lower oxygen demand of the alcohol compared to gasoline.

E-85 AFR would only be about 92% of the gasoline AFR.

Larry
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Old 09-29-2004, 02:52 AM   #5
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not that I really care due to my catless exhaust, but does this fuel have better emissions than normal 93 octane?
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Old 09-29-2004, 03:05 AM   #6
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I wish I could get it here....I'd love to juice it with some toluene
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Old 09-29-2004, 03:46 AM   #7
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Quote:
not that I really care due to my catless exhaust, but does this fuel have better emissions than normal 93 octane?
Yes much better emissions. That is the reason 10% ethanol blends are used here in Colorado and several other locations. The presense of the extra oxygen in the fuel greatly reduces CO and Ozone emissions. It also reduces benzene emissions due to the lower percentage of Aeromatic hydrocarbons being burned. Since it burns cooler Nitrous oxide emissions are also reduced. EPA studies indicate high ethanol blends can reduce emissions by as much as 50%. Also for those interested in CO2 emissions and the whole global warming theory, ethanol being a renewable fuel greatly reduces CO2 emissions because the CO2 released in its combustion is re-captured in the growth of more feed stock for the creation of the next batch of ethanol.

Larry
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Old 09-29-2004, 11:40 AM   #8
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The closed loop doesn't have any affect on utec controlled portions if you use open loop fueling so that shouldn't be a big deal and if you used a constant mixture say 50/50 of this and gas you should be able to tune the closed loop portion to work w/ fuel trims near 0.

I wonder how this mixes with standard gasoline? Does it mix well, or will it seperate over time into its components causing knock at one point when I don't have the extra octane and not at another.

Chuck
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Old 09-29-2004, 12:03 PM   #9
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It seems like a pretty cheap source of alcohol for alcohol injection. I've seen people talkin about payin $10 a gallon for ethyl alc......
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Old 09-29-2004, 12:21 PM   #10
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Quote:
I wonder how this mixes with standard gasoline? Does it mix well, or will it seperate over time into its components causing knock at one point when I don't have the extra octane and not at another.
There is no problem with separation. Alcohol gasoline mixes will stratify if they absorb significant water. In modern low evaporative emission fuel systems there is almost no opportunity to absorbe water.

I've never had any problem at all except the slightly higher vapor pressure of the fuel at about 65% - 75% mix is causing a CEL because the ECU thinks the gas cap is loose. I am currently trying to figure out how to spoof the evaporative emissions system check to eliminate that CEL. I never got that CEL at the lower <30% mixes that you would likely run with standard size injectors.

Quote:
It seems like a pretty cheap source of alcohol for alcohol injection.
Since it contains 15% gasoline it would not mix well with large amounts of water. The gasoline would settle out in that case.

For that your better off buying fuel grade ethanol or methanol from a drag race fuel supplier. That goes for about $2.00/gallon here.

Larry

Last edited by hotrod; 09-29-2004 at 12:59 PM.
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Old 09-29-2004, 12:53 PM   #11
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interesting
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Old 09-29-2004, 02:44 PM   #12
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Quote:
Originally Posted by hotrod
The Stock WRX ECU can handle up to approximately 33% E-85, by volume before you get a check engine light for "too lean" due to the fuel trims being pushed to the max rich settings. Add just a bit of pump premium and the CEL will clear.
Hmmmm... On a related-but-not note, My car had a consistent misfire code when running sunoco 94 (would that be E-10 basically?). This is an early 2002, that I never got reflashed.

Tom
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Old 09-29-2004, 02:45 PM   #13
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if this stuff is cheaper here (i should find out tonight) I may switch to a 50/50 mixture of this and 93 every day to save money and make more power... next question is I wonder how much more power I can make

the next question is are there any concerns with the alcohol wearing out (ie drying out and cracking) rubber hoses or gaskets.. I've heard that is a concern w/ some tolulene mixtures... Would there be any other parts in the fuel system that may need to be considered for more excessive wear or damage by using a higher mixture of ethanol?
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Old 09-29-2004, 03:05 PM   #14
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MustGoFast:

If you have a stock ECU, and stock size injectors I'd suggest you start at about 20% or so and work your way up to see where your ECU will throw the "too lean" CEL. On my car that is near 33% alcohol content in the fuel.

Slidewrx:

Can't say for sure, each major metropolitian area has different requirements for fuel blending depending on how the EPA evaluates their pollution history/problems. If it only happens with that fuel that would suggests to me the engine for what ever reason is not getting reliable ignition on that fuel. You may want to check your plugs. It may be that they are not giving a good enough spark for that fuel. Perhaps old or too wide a spark plug gap, or maybe an ignition coil that is getting a bit weak.

If your still on warrantee, I'd fill up with 94 and take it to the dealer when you get the CEL if you don't have the time or means to trouble shoot it yourself.

Larry
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Old 09-29-2004, 03:17 PM   #15
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Oh it happened a while ago, back in the first year I had it. Took it to the dealer a couple times to get it on record, but once I connected it to the 94, I just stayed away from it. I haven't had the problem in two years.

The sunoco's near me always has the "contains up to 10% ethanol" sticker at the pumps, so I guess that's E-10 (or less). After reading this, I figure I just had a cylinder more prone to misfire than the others, so the misfire code would come up at 10% rather than a 'too lean' CEL at 30+%. I suppose if it was maybe just the plugs, I'll try it again since they have long been replaced.

Tom
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Old 09-29-2004, 04:01 PM   #16
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hotrod... I don't have stock injectors or a stock ecu.. I run the current utec firmwear in open loop and should be able to tune for the higher octane gas and avoid the CEL's.

My concer is still as in my last post about wear items due to increased amounts of ethanol in the system.
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Old 09-29-2004, 05:07 PM   #17
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Quote:
Originally Posted by MustGoFast
hotrod... I don't have stock injectors or a stock ecu.. I run the current utec firmwear in open loop and should be able to tune for the higher octane gas and avoid the CEL's.

My concer is still as in my last post about wear items due to increased amounts of ethanol in the system.
I pulled this from an E85 website.

Will I hurt a gasoline-only vehicle if I use E85?
Yes. Longer-term use of E85 in gasoline-only vehicles may cause damage because of the incompatibility of the alcohol fuel with the parts in gasoline-only engines. Performance and emissions will also be compromised.

I would be wary about using this in high concentrations although Hotrod has been using it for two years without any problems.
I'd love to try it but the nearest station is a two hour drive.
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Old 09-29-2004, 05:27 PM   #18
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Yep I read that part of the FAQ too, but it really doesn't tell me what may be damaged and that is my biggest question. My guess would be the risk of dry-ed out crackedt gaskets or hoses in the system but I'm unsure.. I don't believe there would be any adverse affects to the engine itself.

I also am not really sure how to tune for the different type of fuel. Basically it seems the fuel itself has more O2 in it... does this mean a standard 10.5:1 mixture would actually read leaner (unable to read true mixture) or does it mean that it actually is leaner? I need to understand how my system will read this AFR so I can tune it appropriately. I'm guessing I can runa leaner mix on E85 than on standard gas, but I'm not sure how far I can go. Personally I only want to do this to make more power for reasonable amounts of money as our cars love octane.
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Old 09-29-2004, 05:29 PM   #19
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Think I found my answer to the parts:
The fuel tank, fuel lines, fuel injectors, computer system, anti-siphon device and dashboard gauges have been modified slightly. Alcohols are corrosive. Therefore, any part that comes in contact with the fuel has been upgraded to be tolerant to alcohol. Normally, these parts include a stainless steel fuel tank and Teflon-lined fuel hoses.

So I was pretty on the ball with my guess here...

Edit:
So really if you wanted to run the stuff full time you'd want to replace your fuel lines, and your 02 sensor system for measuring fueling... now onto my previous question about how to tune for it.. if someone can run with that I'd love an answer.
Quote:
I'd love to try it but the nearest station is a two hour drive.
That sucks.. I have about 5 of them within 20 miles of me according to the map.
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Old 09-29-2004, 05:30 PM   #20
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If there is any damage it would be to the fuel system.
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Old 09-29-2004, 05:40 PM   #21
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since the etoh has o in it, a stoich AF ratio is less than 14.7:1.

i think the general consensus on alky blends is to tune to lambda, which takes the different afrs for stoich into account. going by that method, an 11:1 afr (generally safe for 93 oct) gasoline ratio is ~0.75 lambda. with 100% methanol/etoh that's only ~4.7:1. i would assume that a 50/50 would be situated right in between those two numbers, or around 8:1 afr.

you can see that you get octane, but you lose fuel power density. you're squirting a lot more fuel mass.

i noticed when i put in around 10% methanol to a tank, i got around 25 miles less per tank, but i could raise the boost at least 3psi and remain completely knock free!

handy site for afr conversions http://www.rbracing-rsr.com/rsrairfuelmeterl.htm

ken
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Old 09-29-2004, 06:30 PM   #22
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According to page 4 of this PDF (which is a good read, BTW), the stoichiometric a/f ratio for E-85 was found to be 10.7:1.

Also on page 4, they were saying that they had to use warmer spark plugs, as the cooler ones were causing misfires.

Interesting stuff, guys. Note: you have to drive a long way to find non 10% ethanol fuel around the Chicagoland area.
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Old 09-29-2004, 06:48 PM   #23
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Quote:
Originally Posted by ride5000
handy site for afr conversions http://www.rbracing-rsr.com/rsrairfuelmeterl.htm

ken
Great site, that water injection regulator is just what I've been looking for.
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Old 09-29-2004, 07:50 PM   #24
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yeah, that rb racing site is pretty impressive. you can just tell when folks know what they're talking about.


how do you like that downpipe?

fyi: Best 1/4 mile E.T. 7.55; best mph 176.
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Old 09-29-2004, 07:53 PM   #25
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Quote:
Originally Posted by ride5000
since the etoh has o in it, a stoich AF ratio is less than 14.7:1.

i think the general consensus on alky blends is to tune to lambda, which takes the different afrs for stoich into account. going by that method, an 11:1 afr (generally safe for 93 oct) gasoline ratio is ~0.75 lambda. with 100% methanol/etoh that's only ~4.7:1. i would assume that a 50/50 would be situated right in between those two numbers, or around 8:1 afr.

you can see that you get octane, but you lose fuel power density. you're squirting a lot more fuel mass.

i noticed when i put in around 10% methanol to a tank, i got around 25 miles less per tank, but i could raise the boost at least 3psi and remain completely knock free!
You are correct that one should think in terms of lambda and you did end up with an E85 AFR that is close to what I'd recommend for max power with E85. But I disagree with the logic.

According to this document (prepared by the DOE's National Renewable Energy Lab and the National Ethanol Vehicle Coalition), E85 has the following properties:
(R+M)/2 Octane: 96
Stoichiometric Ratio: 10.0:1
Specific Gravity: 0.78

For most fuels used in spark ignition, max torque is achieved with an air/fuel mixture that is about 15% richer than stoichiometric. For gasoline with a stoichiometric ratio of 14.7:1, that works out to 12.5:1. Running an even richer gasoline mixture is "safe" because the evaporation of the extra fuel cools the intake charge to stave off knock; but some torque is sacrificed in the process. The E85 air/fuel ratio that is 15% richer than stoichiometric is 8.5:1. There is no need to add even more E85 for evaporative cooling purposes.

Quote:
Originally Posted by 8complex
According to page 4 of this PDF (which is a good read, BTW), the stoichiometric a/f ratio for E-85 was found to be 10.7:1.

Also on page 4, they were saying that they had to use warmer spark plugs, as the cooler ones were causing misfires.

Interesting stuff, guys.
That document is interesting and, along with the caveat in my owner's manual to never use fuel with more than 10% ethanol, will keep me from ever trying E85 in my WRX.

Everyone should note that E85 conducts electricity whereas gasoline is an electrical insulator.
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