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Old 09-27-2005, 11:24 AM   #126
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Is there any way to figure out what the octane blend is for 30% Ethanol?
The formula I'm using now even using the 118 blend octane rating with 93 octane premium fuel show I should have 99 octane, but you are saying that the octane rating goes down the more ethanol we blend..
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Old 09-27-2005, 11:27 AM   #127
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i was wondering that also

i also wonder if the gas you start with has 10% ethanol in it, does that dimishish the mixing octane rating of the e-85 as you start to add.
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Old 09-27-2005, 03:59 PM   #128
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I stopped by the only e-85 pump in my area yesterday to get a splash of the good stuff...and well they priced themselves right out of the game. $2.79/gal for e-85 when 91 octane was going for $2.84/gal. CRAZY...
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Old 09-27-2005, 05:30 PM   #129
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I wanted to ask this and see what I might be able to do. I can't sell any kind of conversion "kit" per-se. But, can I post the information, test results, and parts used on my website without any reprocussions? I figure they can't nail me with anything bad if I'm giving away the info and listing the already-available parts I used.
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Old 09-27-2005, 05:42 PM   #130
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s_nold ---- It appears that there have been so many folks trying out E85 lately that we've created something of a shortage (at least that is my guess from the pricing I've seen) It's sort of a good news bad news thing -- increased demand will only help get more pump outlets opened up, bad news its putting a squeeze on a very good price split we used to have.


Hamfist --- I would think there would be no problems.

On the octane issue -- I just figure the octane based on a simple 100 octane for the ethanol fraction, and leave it at that. I see no point is splitting hairs over is my tank at 94.5 octane or 95.1 octane. Bottom line is does a specific blend prevent detonation in your car if it does that's all the info I need.

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Old 09-27-2005, 05:57 PM   #131
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I don't see a problem with that. Reason being is that you are not a company selling the parts to make said "kit". Your just providing information on what you used on your car.

I have plans to heavily modify my car and get up to around 400hp. If i use E85 (which i plan on). I'm going to need 1200cc injectors to handle all that. It might be easier to do some staged injection with the Hydra and add 1 or 2 more injectors.
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Old 09-27-2005, 06:59 PM   #132
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I'm a little lost now on the way the E85/gas octane # is being obtained. Anyway, with the way you were calculating the octane rating, what would E10 work out too?
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Old 09-27-2005, 08:09 PM   #133
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Assume that all regular Premium gas is 10% ethanol and 93 octane
E85 is 85% ethanol
WRX gas tank is 15.9 gal
Assume that our blend of E85 is 100 octane

To get 30% ethanol in a tank use this formula as a percentage of your tank.

((10% ethanol * 11.9 gal premium gas) + (85% ethanol * 4 gal E85)) / 15.9 gal tank = 28.9% ethanol final concentration

to figure out octane using the same percentage method

((11.9 gal premium gas / 15.9 gal tank) * 93 octane) + ((4 gal E85 / 15.9 gal tank) * 100 octane) = 94.8 octane final concentration in your tank.
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Old 09-27-2005, 11:04 PM   #134
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I just re-located the source that I was refering to from memory -- I miss-remembered the blending octane slightly --- its not 118 but about 112.5, but as you dig deeper in the text of the report you find that there is no one representative blending octane value.

Check out the following:

http://www.eere.energy.gov/afdc/pdfs/6968.pdf

Otane response page 3-6
Energy content on page 3-9
Materials compatibility starts on page 3-14

Lots of other good info but that should get you started.

As you will note the octane effect of added ethanol (like other octane enhancers) changes depending on the blending stock it is added to.

Larry
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Old 09-29-2005, 07:27 PM   #135
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Wikipedia has this very interesting bit in one of their Ethanol articles about how Brazil has been affected by its own ethanol fuel industry. They've been using it as an automotive fuel for decades.

http://en.wikipedia.org/wiki/Ethanol...ian_experiment
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Old 10-02-2005, 01:36 PM   #136
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Side note of interest...I had a little "fun" on recent cold saturday night. I succeeded in getting about 16mpg. I've never gone through 1/4 tank that fast. The funny thing is, it still gets 25-27mpg on the hwy. Still having cruise and A/C just rocks . Being delivery-boy it still manages about 22mpg in the city.
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Old 10-08-2005, 01:47 AM   #137
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Ham - Not the best results for me of late.. seem to be loosing power. Granted I need a new clutch, but when it does stick I'm getting about 20 MPG at less than normal power. I need to put the hotter sparks in tonight. I really get the feeling I need to tune to get the most outa this stuff so now that I have my new clutch purchased I'll be looking into a piggyback of some kind. I wonder how much a difference your torque chip is making on your setup... maybe it was made for E-85

72psi sounds way too much!! Is that relative to vac at idle or just straight off the gauge? I’ve been up to 55psi which is about 48 on the gauge at idle and I think it’s running rich… you think I might be on the lean side? I don’t know how much the pressure really matters anyway if the ECU is going to correct the map anyway, but it seems to be an issue with my setup.

I’ll pull the old sparks tonight and “read” them.
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Old 10-10-2005, 10:36 AM   #138
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Heck yeah you're lean!!! I have to run high pressures just to get the right mixtures. I'll be upgrading to WRX injectors(440's) over the winter. I'm actually running about 80psi base pressure. No problems so far. The way I've got it crimped on the returen line, though, my pressure drops to about 60 at WOT. It's basically pouring the stuff in, which is good. Around town, I'm still getting about 20mpg without my foot in it. 3,000miles on the stuff and so far so good .
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Old 10-10-2005, 12:36 PM   #139
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For those running a high percentage of E85 in their fuel tank, how does the ECU cope with getting the right A/F ratio? Does it just advance the timing until it detects knock and backs off from there? For E85, what is the proper A/F you'd be looking for when running a wideband sensor?

Thanks in advance for any info on the above.
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Old 10-10-2005, 01:47 PM   #140
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Quote:
Originally Posted by krees23
For those running a high percentage of E85 in their fuel tank, how does the ECU cope with getting the right A/F ratio? Does it just advance the timing until it detects knock and backs off from there? For E85, what is the proper A/F you'd be looking for when running a wideband sensor?

Thanks in advance for any info on the above.
read the first few posts by Hotrod
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Old 10-10-2005, 02:05 PM   #141
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Thanks... I should have reviewed the beginning.
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Old 10-11-2005, 05:52 PM   #142
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My goal with a blower has been to make the most power with the least amount of boost. Once I tune things there, then I can up the boost with smaller and smaller pulleys until the car is plenty fast. Solid 14.0/high 13's at this altitude using all stock components is a good accomplishment. Putting 200 to the crank on an n/a 2.5 I think is pretty damn good with a stock block, bolt ons, and a fuel change. With 5psi, I should be around 275hp. With 8psi, I should be at about 310hp. I've already maxed my stock injectors with running the ethanol. But, I found I can swap WRX injectors in with a cheaply modded fuel rail (thanks, ty ). Will I have enough fuel flow with WRX 440's, or should I step up to 550's? The fuel rails will accept either.
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Old 10-21-2005, 12:51 PM   #143
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Just wanted to report back to this thread on how the 2.0L VW engine has been running. I was up to 50/50 mix of E85/gasoline. No problems from the ECU as far as CEL's. I decided to stay at that mix since it was running fine and there's no way to hook up the WB to this car as it's completely stock.

So, the day before yesterday I filled up on the 50/50 mix again. However, this time I used E10 in place of the regular 87 octane and of course the normal E85. I'm assuming the E10 has a 10% mix of ethanol regular gas? Anyway, I thought that the slightly higher ethanol content might not make a difference.

Last night while driving, I accelerated from a traffic light and the CEL came on. I checked the code and it's P1128 for a long-term "fuel trim lean code" via the MAF sensor. To me, I don't know if this is from the E85 or not? Here's a quote for the code: "One of the most common codes we see on OBD-II Volkswagens is P1128, a long-term, fuel trim lean code. Any unmetered air introduced into the engine can cause P1128 to set.”

I added 4 gallons of 87 octane gas on top the mix and I cleared the code and it has not reappeared. What do you guys think? Man, I really need to read a bit more on E85
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Old 10-21-2005, 04:20 PM   #144
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Yep its from the E85. I don't remember what causes it but I remember reading that E85 does cause that to happen. I bet someone else will explain it in more detail.
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Old 10-21-2005, 05:33 PM   #145
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Go back to page one of this thread and read Hotrod's explaination of what happens to stock cars running E85. Basically you were running lean because you were running more ethanol than the computer/injectors could compensate for.
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Old 10-24-2005, 12:48 AM   #146
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Ethanol carries oxygen in it. That would be "unmetered oxygen" if you think about it. It didn't pass by the MAF .

Would you guys mind goofing off with this a bit? I'm trying to get the page "tuned right". The sound files open okay for some but not for others. It's optimized for IE.

http://www.gt-labs.net/e85conversion.html
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Old 10-24-2005, 12:19 PM   #147
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Quote:
Originally Posted by HamFist
Ethanol carries oxygen in it. That would be "unmetered oxygen" if you think about it. It didn't pass by the MAF

Good point! I was trying to understand the MAF/O2 relationship or was it just some weird VW code
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Old 10-27-2005, 10:50 PM   #148
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The fuel trim code takes a while to come up from what I can tell. The fuel trims need to stay at max for a few days (at least on a WRX before it will throw the code).

It will clear in a few driving cycles after you add enought gasoline to get it off of max fuel trim.

The code is because the ECU is running maximum allowed enrichment to get to stoich mixture under light throttle cruise. If it took that long to throw the code you are near the limit so you could likely get away with slightly less E85 on a continuous basis.

Larry
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Old 10-27-2005, 11:01 PM   #149
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You've got to be right on this one, Larry. The CEL light never reappeared since then . Defnitly must've been it!
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Old 10-28-2005, 12:05 PM   #150
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