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      07-17-2014, 08:03 PM   #1
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E85/Ethanol Thread

So, an offshoot from a dyno thread revealed that we can actually run a mix of E85 in our cars. The generally accept maximum of this is 30% Ethanol, 70% Gasoline (E30).

There are noticeable gains on the dynojet in my pants, but this thread is to further the discussion on the benefits, methodology and cautions regarding running ethanol.

<Discuss>
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      07-17-2014, 08:32 PM   #2
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I am interested in this. The gas station half a mile away has some E85 pumps and it would be nice if I could mix. I am hesitant but would like to hear people's responses as well as what tuners think. Thanks for starting this thread up!
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      07-17-2014, 08:42 PM   #3
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Quote:
Originally Posted by M.Hagen View Post
I think what Coloradoe92m3 is saying is that since the lambda value is nearly identical for ethanol blends as it is for regular gasoline, that the DME does not need to be smart enough to detect the ethanol content in order to achieve the goal of hitting all ignition targets.

The air/fuel ratio conversion is a different value (Lambda =1 will be 14.7:1 for gasoline vs ~12:1 for E30), but as you said the DME does not know it is ethanol, only that it has a Lambda target. As long as the DME is targeting a lambda value (1.0 for cruise and ~0.82-.85 for WOT), it will compensate for the energy density delta of ethanol blends up until the point where the maximum fuel trim is reached. Lambda = 1 for gasoline will ideally have a fuel trim value near zero. Lambda = 1 for an E30 blend will be ~10-15% more fuel, thereabouts.

That is how most OEM's make their cars "Flex Fuel". They no longer use ethanol content sensors, and just use a wider fuel trim limit before an error code is reached.

Ethanol content is great information for adding more timing or more boost based on the blend. I have 5d fuel and ignition tables setup on my Supra so fuel trim, ignition and the closed-loop boost target increases with ethanol content.

You can do fuel with only lambda, but you can't manipulate other parameters since ethanol content is non informed from lambda. However, since the DME has a high ignition target that is rarely reached with 91 octane, adding ethanol is a good way to bring your AKI up and achieve ignition targets.

From a previous thread.
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      07-17-2014, 08:44 PM   #4
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Quote:
Originally Posted by coloradoe92m3 View Post
Has no bearing. Its entire foundation of obd 2 modern AFR management using lambda. As long as fuel pump and injectors can keep up, there is no limit to what you put in tank from a stoic equivrlent factor. Lambda is an actual equivalence of oxygen and fuel. Given e85 has much higher oxygen, it requires much more fuel to balance to desired a/f. So computer keeps adding fuel until it finds its desired balance of lambda .

Only limitation is tuning for timing. Once you can consistently hit max timing without any pulling of timing, there's no benefit to more e85

M3 maxes at 32 degrees and on hot day it takes 94-95 octane to hit that consistently so e30 MUX enables you to hit max timing

It won't show on a dyno if you do a couple runs on 93 and were able to hit max timing but real world driving it will allow you to keep hitting the max
More.
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      07-17-2014, 08:48 PM   #5
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I'll be dynoing tomorrow on a E30 Blend, I'll post my findings shortly there after.

Previous dyno with Trick 101 on the same dyno.
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      07-17-2014, 08:57 PM   #6
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Is that bone stock?
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      07-17-2014, 09:15 PM   #7
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What worries me about running an ethanol mix is ethanol naturally retains more moisture. How do we know this isn't bad for the fuel system? Also, doesn't it also gum up/clog the injectors? Between running stuff to clear the fuel system/injectors, wouldn't it be better to have peace of mind and run a mix of 100 octane racing gas with 91 octane to get a 93 octane mix?
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      07-17-2014, 09:16 PM   #8
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Originally Posted by dereksM3 View Post
Is that bone stock?
That was with Trick 101
Corsa Exhaust
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      07-17-2014, 09:17 PM   #9
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Quote:
Originally Posted by FogCityM3 View Post
What worries me about running an ethanol mix is ethanol naturally retains more moisture. How do we know this isn't bad for the fuel system? Also, doesn't it also gum up/clog the injectors? Between running stuff to clear the fuel system/injectors, wouldn't it be better to have peace of mind and run a mix of 100 octane racing gas with 91 octane to get a 93 octane mix?
Go find fuel without ethanol in it...have fun. Most fuels up here are running 10% ethanol anyways and these cars have built in ability to adjust for ethanol.
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      07-17-2014, 09:26 PM   #10
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True in CA is 10% (maybe more), and every few thousand miles I'm having to put techron in and car feel far better after I run it. We're talking 3x that with the mixes proposed. My worry is also fuel system component corrosion...do we know what the components are made of and do we know what the fuel pump can handle?

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Go find fuel without ethanol in it...have fun. Most fuels up here are running 10% ethanol anyways and these cars have built in ability to adjust for ethanol.
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      07-17-2014, 09:32 PM   #11
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I only run fuels with Techron in them, so yeah.

Re: Components.

Most issues with E85 revolve around the cars stock ability to deliver the fuel. Some will hit 100% of their duty cycle and may cause it to cut out up top. So as long as your fuel system can meet the demand for fuel, you should be good.
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      07-18-2014, 03:01 AM   #12
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Can't wait to see the results!
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      07-18-2014, 04:08 AM   #13
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Likewise. Obviously I want to see a gain over what I made previously, but I REALLY want to see the curves and the AFR.
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      07-18-2014, 06:16 AM   #14
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FWIW, Brazil has a mandatory 25% ethanol in their fuels, and the M3's fuel system is 100% similar to the USDM model. Modern day cars are built to cope with levels of ethanol, so many of the contamination issues are a thing of the past.

you may not make any more whp or wtq versus your previous dyno run using a race fuel blend. The advantage may only be seen after many dyno runs as the engine/oil temps rise as ethanols advantage is cooler combustion chamber temps. <---however, i'm not sure if this applies to non-DI engines though.

your AFR may not change though, as the DME will want to reach for lamba 1, however, your fuel trims may show an increase and actual AFR will be different that reported AFR

here is a good read on wideband tuning between gas and E85, however, i'm having a difficult time finding reads on E85 blends:

http://honda-tech.com/showthread.php?t=3014051

http://www.iwsti.com/forums/2-5-lite...about-e85.html

from that post:

"Before we continue it is good to understand the concepts of AFR as it relates to E85. Because E85 contains less energy per volume it is necessary to use more of it to achieve the same desired result. As such the stoichiometric AFR of E85 at an ethanol concentration of 85% is 9.76:1 vs Petrol at 14.7:1.

You might be thinking it is impossible to tune because our ECU’s only read up to an effective 11.2:1 AFR and can only adjust up to that point. This is not so and here is why. All ECU’s and other stand alone AFR gauges designed use a number called Lambda. That number is the same for Petrol as it is for E85 and is equivalent to 1.0 when either fuel is stoich. What this means is that for a value of 1.0 lambda, for what ever fuel you happen to be using at the moment, it will report its result as 14.7 whether it is E85 or not because the lambda is 1.0 and the gauge is calibrated for petrol. That means when running E85 and your AFR is reported to be 14.7, your real-time AFR is 9.76.
"


essentially, I think that if your engine is reporting lamba 1 or near a 14.7:1 AFR, the car is happy with an E30 mix. I'm no expert though, so maybe Mike Benvo or ColoradoE92M3 can chime in?
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Last edited by spool twice; 07-18-2014 at 07:11 AM.
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      07-18-2014, 09:13 AM   #15
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Great thread, finally something new to read on M3post. Luckily, there's a gas station literally next to work with E85 and E93 ethanol free gasoline (which is what I normally use)

In the most basic terms, can you list the pros and potential cons of running this?
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      07-18-2014, 09:26 AM   #16
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Quote:
Originally Posted by spool twice View Post
essentially, I think that if your engine is reporting lamba 1 or near a 14.7:1 AFR, the car is happy with an E30 mix. I'm no expert though, so maybe Mike Benvo or ColoradoE92M3 can chime in?
Lambda = 1 will report 14.7:1 AFR for the gasoline equivalence conversion.

Lambda = 1 will report ~12:1 AFR for an E30 blend of gasoline/ethanol.

AFR =/= Lambda. AFR is an output when the lambda value is converted to the ratio of air and fuel for a given fuel type.

For example, in my Supra I have an Innovate Wideband. The default fuel type is gasoline, so the reported AFR at Lambda=1 is 14.7. If I go into the software for the wideband controller, I can change the fuel type to E85, the displayed AFR immediately changes to ~9:1 (I run E90-E95). Even though the reported AFR changed, the same lambda value is measured from the oxygen sensor.
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      07-18-2014, 09:45 AM   #17
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Quote:
Originally Posted by W/// View Post
Great thread, finally something new to read on M3post. Luckily, there's a gas station literally next to work with E85 and E93 ethanol free gasoline (which is what I normally use)

In the most basic terms, can you list the pros and potential cons of is running this?
Agreed...the which exhaust is best threads get old. Tech talk is more fun.

I've only ran into one con, mpg drops 2-4 depending on my cycle. The drops are more noticable during steady state cruising, where 70mph will display 26.5 mpg versus 22.5mpg on the OBC. Other than that, everything has been a pro. I have allergies, especially with my eyes, and an E30 mix helps reduce strong exhaust odors since I dont run primary cats.

It makes me wonder if running straight E85 in emissions testing day will assist those who are fully catless or running high flow 200cells?
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      07-18-2014, 09:45 AM   #18
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Quote:
Originally Posted by M.Hagen View Post
Lambda = 1 will report 14.7:1 AFR for the gasoline equivalence conversion.

Lambda = 1 will report ~12:1 AFR for an E30 blend of gasoline/ethanol.

AFR =/= Lambda. AFR is an output when the lambda value is converted to the ratio of air and fuel for a given fuel type.

For example, in my Supra I have an Innovate Wideband. The default fuel type is gasoline, so the reported AFR at Lambda=1 is 14.7. If I go into the software for the wideband controller, I can change the fuel type to E85, the displayed AFR immediately changes to ~9:1 (I run E90-E95). Even though the reported AFR changed, the same lambda value is measured from the oxygen sensor.
Good info, thats a benefit of being able to access the ECU.
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      07-18-2014, 09:57 AM   #19
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Quote:
Originally Posted by spool twice View Post
Agreed...the which exhaust is best threads get old. Tech talk is more fun.

I've only ran into one con, mpg drops 2-4 depending on my cycle. The drops are more noticable during steady state cruising, where 70mph will display 26.5 mpg versus 22.5mpg on the OBC. Other than that, everything has been a pro. I have allergies, especially with my eyes, and an E30 mix helps reduce strong exhaust odors since I dont run primary cats.

It makes me wonder if running straight E85 in emissions testing day will assist those who are fully catless or running high flow 200cells?
Fuel economy is not a huge concern for me, as the E92 is my weekend car now. And I actually like the smell of a catless S65 in the morning

I was thinking more like which part would need replacing more often. I read potententially 02 sensors and spark plugs? What about things like fuel pumps? Sorry for the noobie question, this is all kind of uncharted territory for me,
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      07-18-2014, 10:20 AM   #20
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Quote:
Originally Posted by W/// View Post
Fuel economy is not a huge concern for me, as the E92 is my weekend car now. And I actually like the smell of a catless S65 in the morning

I was thinking more like which part would need replacing more often. I read potententially 02 sensors and spark plugs? What about things like fuel pumps? Sorry for the noobie question, this is all kind of uncharted territory for me,
To me the gains are not worth the hassle. Running e85 on a NA car is a waste of time. Easier and better results from a small supercharger
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      07-18-2014, 01:15 PM   #21
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Not everyone wants a blower. Some want to extract most out of engine. Not to mention it's same price as 91 and mileage decrease for 30 percent mix is negligible. If I had access to 93 at pump I wouldn't bother but 91 in hot weather gives up 10 degrees of timing measure on bt
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      07-18-2014, 01:59 PM   #22
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I was curious after seeing this so last night I put in 3 gallons of e85 and topped the rest off with 93. After a couple pulls I feel like there is a difference. More throttle response and the car seems to pull a bit better. The temp here is in the mid 90's so maybe its simply offsetting that. I have test pipes and a BPM tune as well.

I saw someone mention their exhaust note changed afterwards and I can say that does seem to be true. The exhaust tone seems to be more mellow.

Overall it doesnt seem like a huge difference but if you can sense a change I guess thats worth something.
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