Testing as done by AMS:
I'm not sure what initially sparked our interest in E85 fuel. Somehow, one of us was surfing the internet and stumbled upon it, let a few other people know, and eventually everyone had just as many questions as we had answers! Using our searching capabilities we scoured every information source we could find on the fuel. There are three major questions that everyone asks about E85; what is the advantage of it, what does it do to my fuel system and what do I need to do to run it? Two of these questions can be answered easily, while the question of what it does to your fuel system remains somewhat unanswered.
E85 is supposedly a corrosive fuel if you take into account that it is 85% ethanol. The properties of ethanol, while less corrosive than its counterpart methanol, are listed as being able to corrode aluminum, weaken and eat through rubber fuel lines, and do other nasty things to components commonly found in your fuel system. Original Equipment Manufacturer's (OEM) fuel systems have been made more tolerant of ethanol than they were in the past. Normal gasoline can contain up to 10% of ethanol, which OEMs have had to deal with by federal regulation. None of these companies, if they are smart, have done the absolute bare minimum to be in compliance with the fuel that we use today. If they had, there would be problems with the fuel systems that would incite huge numbers of recalls and eventually cost them more money. However, it is very tough to figure out how far they have gone with their ethanol compatibility without testing, or the exact chemical makeup of each part. There is no real way for us to know how the factory fuel system on each particular car is going to hold up until someone is brave enough to test it.
The Mitsubishi Lancer Evolution is a relatively new vehicle with parts that aren't exactly easy to find in a junkyard, or used for a reasonable price. If you break something in your brand new EVO 9's fuel system because you were running E85, chances are you warranty claim is going to be denied. The best thing to do in this situation for us was to use all the broken pieces of various fuel systems we had and submerge them in containers of E85. While the test is not the most scientific thing I have ever done, it serves its purpose. In our 6 containers we have:
A stock EVO fuel sending unit
Various fuel lines of different material, including the stock EVO lines and Stainless Steel braided line
A DSM fuel injector
fuel injector o-rings and isolators
bare aluminum
anodized aluminum
stainless bolts
A disassembled inline Walbro fuel pump
An extra jar filled with e85
Our extra jar of E85 not only serves as a control, but allows me to monitor how much water this fuel is going to soak up. Ethanol is a very hydroscopic liquid, which means it likes to absorb water. When there is roughly a 1% content of water the ethanol and gasoline will separate and obviously start to cause some issues.
After about 4 months, there has been no change in the composition of the materials that are submerged in the containers. There has been a change in the color of the fuel in a couple of the jars. The jar with the fuel lines in it is the darkest of them all. Some of the fuel line I used, had been previously installed on a car and it had some electrical tape on it. The electrical tape has not fared well at all! I would not consider this to be a valid concern unless you are planning on holding back in excess of seventy-five psi with electrical tape. If you do, you are bound to have other problems with your fuel system. The other container, with a used fuel sending unit in it, is also quite dirty. The used fuel filter on the end of the pump was visually very dirty before it was submerged in E85. This proves some of what I have read about ethanol and its cleaning properties. In several articles I have seen, it is recommended that you change your fuel filter 50 miles after you start to run the fuel in your vehicle. I would say that this is an accurate estimate of the time allowed before you change your old filter. If you have an older vehicle, I would be inclined to tell you change it once again after that in order to insure that it does not become restricted with all of the debris being cleaned out by the ethanol. The rubber lines are not cracked, or weakened, my aluminum has not yet corroded and everything in my Walbro pump seems to be the same as I left it a few months ago. So far, so good, and now we need to test this on somebody's car!
It wasn't long after I told Eric, our sales manager at AMS, about the test results that he was seriously considering using it in his car. After a few days he decided it was time to do it and we had to figure out what we wanted to do about the fuel requirements for his car. Under full load the rumor is that the use of ethanol requires about 30% more fuel. The reason you need more ethanol to get the same power is because of the fuels lower energy content. This fuel also will burn slightly colder, and have a higher resistance to pre-ignition and contains more oxygen than conventional gasoline. Although the ethanol has only a slightly lower temperature during combustion, it takes much more heat to get it to change phase into its gaseous state. When ethanol changes phase, it does it very easily because of its low boiling point. The energy (heat) used for the ethanol to change phase is three times greater than that of gasoline. This heat gets pulled from the incoming air charge, and the surrounding material in the combustion chamber, runner ports and the intake manifold. It is easy to see how this could be advantageous to the production of power in high temperature, high combustion pressure engines. For comparison ethanol uses 410 btus/lb (heat energy units) to vaporize, and gasoline uses only 135 btus/lb.
We already had a good handle on the injector duty cycle he was running (making around 335hp at 22 psi on 93 octane) it was relatively easy to put him in the right size injector for his car. The injectors supplied with the car from the factory are 560cc units, fed by a very capable fuel pump at about 85% duty cycle. Using the 30% theory we should be able to get away with an injector that flows about 728ccs at the same boost level. However, we want to turn the boost up to get the most out of the supposed 105 octane fuel. We decided to use 880's and switch it up to a Walbro fuel pump which flows even more than a stock EVO 9 unit. Everything else in the fuel system will be left unchanged based on our findings from the above.
The stock ECU does not look at an air/fuel ratio for closed loop fuel trim adjustments. The stock ECU from this car and any other with any type of oxygen sensor looks at a value called lambda. This value of lambda always equals one when the stoichiometric air/fuel ratio is reached for whatever fuel is being burned. For example stoich on gasoline, which everyone is most familiar with is 14.64:1 and also is equal to a lambda value of 1. The stoich air/fuel ratio of ethanol is about 7:1 and also equals a lambda value of 1. All oxygen sensors, wideband or not, measure in lambda and then convert that value to the air/fuel ratio of your choice. In the stock ECU's case it does not waste time converting the value and uses the lambda value to get the idle, cruising and part throttle air/fuel ratio in check. Knowing this, all I had to do was correct the scaling used in the ECU so that I could get it as close as possible and let the ECU do the rest. With the drivability hammered out, Eric drove the car around for the next few days before it was time to get tuned.
-Eric's Mitsubishi Lancer Evolution IX SE
Relevant Power Modifications
AMS Full Turbo Back Exhaust
AMS Front Mount Intercooler
AMS Lower Intercooler Pipe
AMS Manual Boost Controller
AMS 880cc Injectors
Blitz Drop in filter with stock airbox
Walbro Fuel Pump
GSC S1 EVO 9 Cams
Once the car was on the dyno I made a few pulls to see where the car was at on the old tune. With the injectors scaled correctly, the tune was not far off from where it needs to be. I quickly started to notice a trend of the car liking more and more fuel. E85 definitely likes to run a richer (lower) lambda value under full power! As I was adding in fuel, power was staying the same and the knock noise was going down. The power numbers are roughly similar to the numbers on pump gas at the same boost level. On this car, there was no added benefit to simply running E85. Any gains were going to be realized with more boost and ignition timing. Utilizing a manual boost controller on stock EVO 9 turbo I managed to tweak it out to about 28 psi of boost. With the fuel dialed in, the next thing to do was to increase timing to realize any additional gains. Sadly and surprisingly, the car would only take very conservative timing values when in comparison with 100 octane gas out of the pump. Previously I have experienced 100 octane pump gas being able to make a bit more power than this and be much less sensitive to timing and boost changes. The timing the car ended up using is similar to a car on a 93 octane tune at 21psi of boost. While the car is making about 380ft lbs of torque, and 365 wheel horsepower, I am a little disappointed with the results tuning wise, and the cars ability to handle what I think it should.
The octane rating of 105 may not be entirely true, or not on the same scale as 105 octane in a regular gasoline mixture. If I had to guess an octane number it would be somewhere between 95 and 100 octane. The other difficult thing about E85, especially in the northern states, is the fact that the actual blend of ethanol to gasoline is changed throughout the year to compensate for the colder weather.
Ethanol is NOT a cold weather fuel. Cold start compatibility with ethanol on OEM vehicles usually includes a heated fuel line before the fuel rail in order to get the ethanol hot enough to vaporize and ignite. Under a certain temperature, it does not matter how much or how little ethanol is injected, it simply will not vaporize or be able to reach its flash point. The flash point of ethanol is actually 55.4 degrees Fahrenheit in its pure form, while gasoline will reach its flash point to temperatures as low as negative forty-five degrees. To combat this phenomenon, the gasoline to ethanol content is raised. The gasoline that we had in Eric's car could have been E80, or possibly E70. The stickers on the pump in Illinois specify that the "E85" will contain at least 70% ethanol. Unfortunately, there is no way for us to tell utilizing the information that we currently have available. Cars that are equipped to run ethanol from the factory have a special sensor inside the gas tank which is able to tell the amount of gasoline to the amount of ethanol and change the vehicles tune accordingly. There is currently no way to adapt this to the stock ECU, although there are a few pioneers out there leading the way to get this done. I have heard reports of several people being able to adapt these sensors into a stand alone and have the fuel and timing trimmed accordingly. Ultimately, this will be the best method of running this fuel out of the pump.
