E85 Ethanol % Test - Test it at your fuel station

[swbca]

E85 can contain anywhere from 51% to 85% (or more) alcohol. They transition to less alcohol for the winter in cold climates to maintain vapor pressure. The octane goes up to 105 (estimated) with "real" E85. My Holiday station has E88 this morning in mid-september.

If you can do simple math in your head, you don't need a spreadsheet or an application to check Ethanol % of your local E85.

Why do I care ?
I am using my 2014 A4 (flex-fuel) for Track Days, with a Stage 1 APR flash. They said "real" E85 adds about 40 additional horsepower with the APR program set at 92 octane.

Get this "test kit" in 15 minutes -24/7 at many Walgreens stores
You don't need to order a kit from Amazon or locate a calibrated test tube from a lab supplier.
You just need a baby bottle with good calibration detail. Many drug stores are open 24/7 and they're everywhere.

Items needed:
1. Smile & Save 4-pack of baby bottles from Walgreens
2. A black magic marker
3. A jar or large cup that can safely hold 8 liquid OZ without spilling.
3. A bottle of water

The 23ml layer of gasoline below calculates to 88.5% alcohol (E88.5)


This brand from Walgreens doesn't soften with fuels and has better measurement lines than most.


Steps
1. Carefully highlight the 200ml and 250ml lines on the baby bottle with the marker.
2. Put about a cup of E85 fuel in a wide mouth jar or measuring cup while pumping a couple of gallons of E85 in your car.
3. Move your car to a parking space at the fuel station.
4. Pour E85 into the baby bottle to the 200ml line that you have highlighted with magic marker
5. Add water to the 250ml line you have highlighted.

6. Put the top on the bottle and shake it a little without shaking liquids out of the top.

7. Set it down for 2 or more minutes.

8. Read the float-line between the gasoline and water/alcohol mix (227ml in image above)

Calculate . . . using example in image above 250-227 = 23ml of gasoline
23/200=.115, or 11.5% gasoline, or 88.5% alcohol

What we found in Minnesota
Mid September 2015 (they use less alcohol in the winter)

SuperAmerica I checked only one station
75% or E75 (their pump has a permanent sticker saying 70% Minimum)

Holiday I checked 2 stations, 50 miles apart
88% or E88 (their pump has a permanent sticker saying 51% minimum)

There is no E85 within 50 miles of Brainard International Raceway so I bring 18 gallons to the track in 6 gallon gas cans for a mid day refill. (this is a bit scary)

[Mat@1975]

Brilliant !

[AudBoost]

Very informative write up! Thanks!

[cspcrx]

Thanks I need to test the one by my house. I have been adding 3 gallons on top of 91 octane at fill up to get me to 93 octane. Car really liked it during the summer heat here in Phoenix.

[S4 00 2.7]

cool stuff, thanks.

[skiracerblah]

Zeitronix sells an ethanol gauge with an ethanol sensor that gets plumbed into the return fuel lines....

http://www.zeitronix.com/Products/ECA/ECA.shtml

[jimrobbington]

Thanks I need to test the one by my house. I have been adding 3 gallons on top of 91 octane at fill up to get me to 93 octane. Car really liked it during the summer heat here in Phoenix.

Samesies in Denver. My station says minimum 70% but I've never tested it.

[aysix]

E95 here in vegas...bitches.

[jokingjimmy]

E95 here in vegas...bitches.

Lol

[skiracerblah]

fyi, a few years ago in Norcal somewhere a bunch of Evo's and Subaru's were sustaining engine damage and all were filling up at the same station. They filed a complaint with the regulators and the regulators tested the fuel which ended up being E50...

So, Test your fuel!

[rtl5009]

Why test so much? The same principle applies to a small amount. I used a test tube lol.

[rtl5009]

I've done a lot of testing. I have seen e89-e68 at pumps in western PA depending on time of year.

[cspcrx]

How did you test it in PA. I see your in Phoenix now. I need to look for a sticker stating the minimum level. I have never noticed one.

[rtl5009]

Calibrated Hydrometer. Pretty much the same test above but with a calibrated test tube and scale.

[rtl5009]

Thanks I need to test the one by my house. I have been adding 3 gallons on top of 91 octane at fill up to get me to 93 octane. Car really liked it during the summer heat here in Phoenix.

This is not safe at all to do.

[rtl5009]

How did you test it in PA. I see your in Phoenix now. I need to look for a sticker stating the minimum level. I have never noticed one.

New standard is 50 min. In phx I doubt it would ever go below e75. They add gas (mix expensive) to aid in cold starts. Not a prob in Phoenix.

[Usa]

How do you mix E85 / 93 to achieve something close to where it would be safe to run a 100 Octane file from APR?

[AudiS4TW]

From time to time I do a 60/40 blend of 91 pump (76) and e85 (Propel) with the race map from the GIAC Stage 2 software for my S4. No upgraded fuel lines or aftermarket fuel pump. Slight increase in power using the butt dyno, and eventually you get the CEL light later on due to the air-to-fuel ratio running "lean", which you can clear after you fill up the tank with just petrol gasoline. CEL doesn't come back on after you do this. No issues so far. I've done this at least five times on my way to a racetrack. It's an alternative to pumping 95 octane gas, which is non-existent in Southern California. We have a couple gas stations that have 100 octane unleaded gasoline in San Diego, but it costs $8-$9 per gallon.


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[AudBoost]

How do you mix E85 / 93 to achieve something close to where it would be safe to run a 100 Octane file from APR?

I wouldn't recommend doing this unless you know the ethanol content of the E85 you are using. Reffer to what skiracerblah said in post #10.
E85 has octane rating of ~105. If mixed with 93 you would need to make E54 (54% ethanol) to get 100 octane. So on an empty tank you would need 10 gallons of E85 and 7 gallons of 93. Assuming the E85 you are filling up with is in fact E85 and not a lower ethanol concentration. Use the chart "Octane result from blending 2 fuels" from this site: http://www.intercepteft.com/calc.html.

**The issue here is that the stock fuel system can only handle up to ~E30 before fuel trims max out. Because ethanol requires more volume (more fuel flow) the stock fuel system can't supply enough fuel so your car will run lean. Unless you have an upgraded HPFP I wouldn't suggest going over E30.**

[infinkc]

How do you mix E85 / 93 to achieve something close to where it would be safe to run a 100 Octane file from APR?

http://www.intercepteft.com/calc.html
bottom table.

[dl73]

I wouldn't recommend doing this unless you know the ethanol content of the E85 you are using. Reffer to what skiracerblah said in post #10.
E85 has octane rating of ~105. If mixed with 93 you would need to make E54 (54% ethanol) to get 100 octane. So on an empty tank you would need 10 gallons of E85 and 7 gallons of 93. Assuming the E85 you are filling up with is in fact E85 and not a lower ethanol concentration. Use the chart "Octane result from blending 2 fuels" from this site: http://www.intercepteft.com/calc.html.

**The issue here is that the stock fuel system can only handle up to ~E30 before fuel trims max out. Because ethanol requires more volume (more fuel flow) the stock fuel system can't supply enough fuel so your car will run lean. Unless you have an upgraded HPFP I wouldn't suggest going over E30.**

I tend to agree, though a recommended 'max' number (~E30) is also a function of your airflow as well - whether you are Stage 1, Stage 2, the DA where you are, etc. all impacts this significantly, so while E30 may work for most/all, E40+ may also work for some. And whether your resultant octane is viable on a tuner's race program requires logging to see how aggressive their timing advance is for the '100' program, as this varies as well. Maybe 98 octane would work for some. I'm just speculating on any numbers but careful testing and logging is the way to go.

[pdqgp]

From time to time I do a 60/40 blend of 91 pump (76) and e85 (Propel) with the race map from the GIAC Stage 2 software for my S4. No upgraded fuel lines or aftermarket fuel pump. Slight increase in power using the butt dyno, and eventually you get the CEL light later on due to the air-to-fuel ratio running "lean", which you can clear after you fill up the tank with just petrol gasoline. CEL doesn't come back on after you do this. No issues so far. I've done this at least five times on my way to a racetrack. It's an alternative to pumping 95 octane gas, which is non-existent in Southern California. We have a couple gas stations that have 100 octane unleaded gasoline in San Diego, but it costs $8-$9 per gallon.

Are you seriously stating you do this with no F's given? WOW! You must have never seen a motor pop from a lean situation. Let's just say I've seen several. No thanks. My autocross car was an MS3 that I had putting down 290hp/270tq and it was solid. Others pushed it to get to 315/320hp ignored lean code, cleared them out and went boom. Rod through the lower passenger side. Several just went boom at 4k rpms under light throttle too.

IMO mixing E85 given all that's known about the variance in the mix is just playing Russian Roulette with your motor. Either get do it right or realize you're likely just getting lucky. I hope those that do run a scan when they do.

[rtl5009]

There is no agree here. This is right, and then there is wrong.

Throwing codes for lean? Yea , that's cause the system is lean due to the fuel mixture. A race program adjust TIMING, not fuel delivery for a new stoich AFR . While the car has safety adjustments it can only adjust so much. E85 stoic AFR is 10.0 while gas is 14.7. Under load you want to see a .78-.80 lambda on gas and a .80-.83 lambda for E. Notice has gas needs to be more rich for safe burn, you still have mostly gas in the tank and you have now leaned out the system.

You WILL melt a piston ring doing this. It is only a matter of time.

[AZT]

No one should ignore lean codes, but this engine monitors wideband lambda at all times and can detect the first hint of an unexpected deviation - and will cut throttle/boost long before it gets the point of melting things.

[jimrobbington]

This is not safe at all to do.

Lol, ok. So the hundreds of 335 guys running 50/50 mix on stock engine are all retarded i guess. 3 gallons in a 16 gallon tank is well within the abilities of our ecu to adapt to.

[derek.kritz]

Just monitor your e85, that's all. And don't go crazy high with the mix if you don't have a tune for it. I put in about 3 gallons per tank fill up. No issues. Waiting patiently on EPL's full E85 tune...


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[AZT]

For best mixing does one recommend putting in the E85 first or last, or does it matter? The post made me think about how it may tend to settle or stratify with regular gas (though obviously it is not the same principle since we aren't adding water!)

[rtl5009]

Lol, ok. So the hundreds of 335 guys running 50/50 mix on stock engine are all retarded i guess. 3 gallons in a 16 gallon tank is well within the abilities of our ecu to adapt to.

There is a key difference in what they are doing.

[derek.kritz]

For best mixing does one recommend putting in the E85 first or last, or does it matter? The post made me think about how it may tend to settle or stratify with regular gas (though obviously it is not the same principle since we aren't adding water!)

I like putting the E85 ON TOP of the petrol. I threw a lean code once putting the alcohol on the bottom of the tank. The tank was nearly empty though.


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[cspcrx]

This is not safe at all to do.

? Why others mix E85 and 91 all the time. ?

[derek.kritz]

? Why other mix E85 and 91 all the time. ?

It's fine. Putting a few gallons of E85 in your tank is a good thing. Especially on a tunned engine in the heat of summer. Keeps that timing pull at bay. Don't go 100% if you arn't tuned for it though.


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[jimrobbington]

There is a key difference in what they are doing.

Please elaborate how it's different?

? Why others mix E85 and 91 all the time. ?

X2

[cspcrx]

That is what I figured. My car is totally stock and it just feels like a slug in the summer. The highest fuel we can get here is 91 so I started running a mix that would get me to 93. I could feel a difference and never had any codes or anything.

[derek.kritz]

That is what I figured. My car is totally stock and it just feels like a slug in the summer. The highest fuel we can get here is 91 so I started running a mix that would get me to 93. I could feel a difference and never had any codes or anything.

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[rtl5009]

No one should ignore lean codes, but this engine monitors wideband lambda at all times and can detect the first hint of an unexpected deviation - and will cut throttle/boost long before it gets the point of melting things.

If it monitors and adjust to WB lambda then why do people get lean codes? It's can monitor all day, however you will reach a point where the system cannot course correct as the system is designed around the use of the intended fuel.

[rtl5009]

Please elaborate how it's different?

X2

JB4 cars have multiple maps that are specifically tuned for different e85/gas ratios, which have modified timing and FUELING. A 100 oct file on our car is set up for the knock resistance of 100 oct fuel over 91/93, which is timing. It doesn't not change fuel delivery.

[AZT]

If it monitors and adjust to WB lambda then why do people get lean codes? It's can monitor all day, however you will reach a point where the system cannot course correct as the system is designed around the use of the intended fuel.

Yes, the lean codes will come when it reaches the limit of its correction. That doesn't mean you are running dangerously lean/high EGTs (yet) and it should go into limp/protection mode before it even gets to that point. Unless the tuner crippled some of the factory safeguards. I am not sure anyone has hit this exact scenario on their S4 (though plenty have gone into limp mode for other reasons - it does exist). The B5 S4 limp mode was notorious when the ECU felt something dangerous going on (even if you disagreed!) and that engine technology was almost 20 yrs ago.

[derek.kritz]

Yes, the lean codes will come when it reaches the limit of its correction. That doesn't mean you are running dangerously lean/high EGTs (yet) and it should go into limp/protection mode before it even gets to that point. Unless the tuner crippled some of the factory safeguards. I am not sure anyone has hit this exact scenario on their S4 (though plenty have gone into limp mode for other reasons - it does exist). The B5 S4 limp mode was notorious when the ECU felt something dangerous going on (even if you disagreed!) and that engine technology was almost 20 yrs ago.

Correct. I'm yet to hear a single person throwing a rod on a B8 S4 from running lean. If anyone has, please post the link.


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[rtl5009]

No one has ever thrown a rod from being lean.........

You melt things.

[pdqgp]

No one has ever thrown a rod from being lean.........

You melt things.

my comment was just an example of what was common on MS3's with guys screwing around with E85 without supporting mods. Either way, mixing E85 to me is like $9 plastidip on the wheels of a $60k car. Just go get the tune and supporting mods for E85 and do it right.