conversation about plant juice, aka e85

[paradime]

A few years ago I spent months researching e85 before making the decision to build my auto-X SR 510's fuel system to run on it. when I posted this on my build thread I spent a bunch of time defending that decision. Some saw it as the black plague, others as hippy snake oil, but most saw it as a threat to their beloved tried and true gasoline. Most of the support I was getting came from guys in Australia who'd been using e85 for years.

 

In the interest of time and sanity, let's cut any political shit off right here before it starts: This is not a tree hugging anti fossil fuel rant, this is about the search for performance. I've run into so many people who think that because ethanol is an eco-friendly carbon neutral fuel it's somehow anti American. These same ignorant haters were saying the same thing about Datsuns a few years back. Personally if it makes my car go faster I couldn't give a flying fuck where it comes from or who it threatens. 

 

Over the years I've read a crap load of conflicting information about the performance advantages, and potential dangers of e85. There is a huge amount of disinformation out there, and I had no idea who or what to believe. I thought I'd dig deeper than the typical anecdotal car mag article, the over-enthusiastic crusaders in the hippie environmentalist encampments, and the wanker WAGs in the tuner crowd. With some hunting I found solid answers from scientific research studies, data sheets from NHRA, SCCA, and formula D teams who've done extensive track testing with e85. Bottom line, e85 isn't for everybody, but for modern EFI turbocharged engines, it's a very real performance fuel option. Here's what I found.

 

Is it an eco alternative fuel, or is it a performance fuel?

 

The short answer is YES. Undoubtedly there is a disconnect between the broader public's view of e85 and the performance crowd's view. It's a matter of perspective. For the average John Q Public driving a Flex fuel Ford F150, with 9.5:1 compression, more likely he's looking for the most economical way to get to work. So with 30% less fuel efficiency, if e85's $ per mile ratio isn't on par with gas, what's the point? 

 

For the performance minded, it's when you raze compression that e85 starts to make real sense as a high performance fuel. With forced induction you obviously get more fuel mixture in the combustion chamber, but under higher relative compression, e85's volatility increases and it releases more of it's potential energy with an octane rating of 107, while at the same time it burns cooler, cleaner, and is less prone to detonation than race fuel. (more on that latter) For example, N/A drag cars are running it at 16:1 compression. Even with 112 oct race gas you'd be pinging at idle at that compression. To someone pushing the performance edge, all this adds up to a great alternative to high octane race fuel at 1/4 the price. With this in mind it's easy to see why there's a disconnect in general public's and the tuner's viewpoints, because they are effectively comparing apples and oranges. 

 

So what's behind e85s bad rap? 

 

In all reality, politics, and green mania aside, e85 has it's down side; it's 25-30% less efficient, it can be hard to find, it's not as stable as gas, it's sensitive to water contamination, in cold clement it's blend ratios vary from 70 to 85%, and the biggy, it is more corrosive to rubber than gas. If you look around the internet you'll find wild claims of ethanol eating aluminum, unregulated refining methods, rampant contamination, motors blowing up and so on. Reading these claims in countless forums, I found one universal theme, it was either coming from hackers who didn't know what they were talking about, or blatant disinformation form oil interest. Yes, If you don't do it right, as with any fuel, it will bite you in the ass. Yes ethanol is corrosive to rubber and silicon, but not to anything metal, or polypropylene/vinyl plastics.

 

You might recall a few years ago a sudden increase in corn based ethanol production caused a huge spike in food based corn prices, and shortly after that ethanol lost it's government subsidy of $.35 per gallon. News reports at that time were saying this spelled the end of ethanol as a viable alternative fuel. If you peel back the curtain a bit you'd find the end of the gov's ethanol subsidies was because of a preplanned end date. This subsidy was implemented years ago and was intended to get ethanol product up and running. Despite the oil companies lobbying efforts to push the gov to end it earlier, these subsidies ended as scheduled. Today ethanol production has shifted to second generation non food crops and it's future is sable enough to be an A grade investment according to Standard and Poors

 

What's the up side?

 

1. Increased power: 

This is a claim that has seen it's share of skepticism and controversy, so I found a reliable scientific source of information. An SAE laboratory tests actually proves that on a N/A motor ethanol provides greater engine torque and knock tolerance than than 92 oct e10 pump gas. For example, 5 degrees of spark retard are required with E10 gasoline for each compression ratio increase, while the much less sensitive E85 requires only 2 degrees of retard for each compression ratio increase. This sounds good, but with forced induction e85 becomes a whole other beast,

 

Ethanol is not in and of itself a high performance fuel, but it does let you push compression far beyond the normal detonation limitations of pump gas, and even straight race fuel. Detonation occurs when excessive heat and pressure in the combustion chamber cause the air/fuel mixture to auto-ignite. e85 is not as volatile in that respect, but that has nothing to do with the stored potential energy of each fuel. In all reality gas has more SPE than e85, but there are limitations to how much, or how efficiently you can get that energy out of gasoline. It is that lower sensitivity, and natural cooling effect of ethanol during atomization that keeps auto-ignition from happening. This allows for higher compression which releases greater potential energy, thus producing more power. Greater access to it's SPE is also one of the reasons why e85 burns cleaner, because more of it's energy is converted during combustion. 

 

If you want to really geek out on this there are lot's of peer reviewed research studies out there that show very detailed data on the performance characteristics of e85 Heres an abstract below of one covering this very topic. 

 

An Experimental and Modeling Investigation into the Comparative Knock and Performance Characteristics of E85, Gasohol [E10] and Regular Unleaded Gasoline [87 (R+M)/2]

 

Number: 2007-01-0473

 

Published: 2007-04-16 

 

Publisher: SAE International

 

 http://beta.papers.sae.org/2007-01-0473/ m 

 

2. Cooler combustion:

 

Test studies report an average difference of 218 deg F lower peak exhaust gas temp than 87 oct E10 pump gas. I must admit, I have no idea how they defined base optimal tune for each fuel, or I should say I couldn't understand how they did it. Still, with a peak EGT of 1650 F on an average turbo charged motor, 200 deg is significant. As any turbo guy will tell you, heat is the number one barrier in getting the densest air/fuel mixture into the combustion chamber. To that end we use bigger inter coolers, water spray, ducted fans, heat shields, on and on. Take 200 degrees right of the top and you can see the benefit.

 

3. Zero carbon build up. 

Shit, that ones self expiatory.

 

4. Average price per gallon of $3.50

OK it is 30% less milage, but 105 oct race fuel is $12 per where I live. you do the math.

 

And 5. last but not least it is better for the environment.

 

 

What is required to convert to e85?

 

Honestly it's not for the faint of wallet, or the average weekend warrior. A list of fuel system upgrades are:

 

Teflon fuel lines

Bigger fuel pump, maybe two ethanol approved

Silica tank vent

Bigger high quality injectors (see calc below)

Adjustable fuel pressure regulator 

Tunable ECU,

REALLY GOOD DYNO TUNER WHO KNOW E85

O2 sensor.

 

Tuning for e85 is not as easy as simply upping the fuel delivery by 30%. It requires different timing and fuel curves, and the O2 levels need to be monitored by the ECU. plotting these curves is not something you can DIY by data-logging hard accelerations. It requires a dyno and a tuner that knows his shit.

 

When selecting injectors it's a good idea to select a slightly smaller injector than needed. You can make up the difference with higher pressure, but you will also get better dead time results with smaller sprayers. A good rule of thumb to select an injector than will run peak hp at no more than 85% duty cycle.

 

For instance, say I determined that I would need 1250cc injectors to produce 450hp on e85. I could get 1000cc injectors and push fuel pressure to 57psi to get 1250. That way I will get a much better dead time response than I'd get with a 1650, or 2000cc injector. 

 

Here's a quick calculation to determine the correct injector size for the amount of hp you'd like to produce. 

 

HP (1) X BFSC (2) Number of cylinders X duty Cycle (3) 

 

* Brake Specific Fuel Consumption: This is the amount of fuel consumed (in lbs. per hour) for each horsepower made. This should be .45 to .50 for naturally aspirated engines and for Turbocharged engines .60 to .65 

 

To calculate the injector size for E85 use a multiplying factor of 1.47 . The 1.47 number represents the difference between the stoiciometric fuel ratio of gasoline and E85. Gasoline is 14.7 and E85 is 10.0

 

Keep in mind, all these numbers are averages and can depend on tuning, boost, and so on, but this will get you in the ball park. 

 

A new development in the market are electro-voltaic sensors that can monitor ethanol levels and average it to an O2 sensor so your ECU can adjust it's map accordingly; basically turning any motor into a flex-fuel system. Again not a job for the average tuner/programer,

 

Measuring Ethanol Content Vai O2 Sensor 

m http://www-personal.umich.edu/~annastef ... nkovic.pdf m 

 

Cheers, and I hope this come in handy for anyone interested.

[paradime]

Fixed

[Cpl620]

mother of god, someone did their homework. Ive been hearing that even though its less emissions that it emits, that the carcinogenics it does emit are worse for the environment. that may just be green thumb hippie propaganda, who knows. ive seen nothing but good things as far as power results for the performance side of things, but i know it take some money to set up and in some cases can shorten the life of the engine, with the seals and everything.

[mklotz70]

The bit about carcinogens is probably coming from the oil companies!! lol

 

Great info!  I didn't think I'd even read this post, but I'm glad I did.....quite interesting!

[tr8er]

I'm all for ethanol in race gas, for an engine that is tuned and built for it. I honestly hate that it wasn't really optional at the pump for a long while. Even E10 was a pain with water in the tank. Sucked it right out of the sky. Ethanol kills small engines with diaphragm carbs. And it is worse for the environment in some ways.

 

BUT. Objectively looking at it as a race fuel source, it has all the merit you need. I'd love to test (joy) ride two cars with $20 of gas. One E85, and the other petrol race fuel. Both cars tuned right. I would not at all be surprised to find ethanol the winner.

[paradime]

Honestly, that's the first time I've heard the higher toxin thing. I'm with mk though, sounds like oil company propaganda. The performance of e85 vs. race gas really depends on the platform being used. For a N/A engine you'd have to push compression way beyond what gas could handle, so you couldn't really do a head to head. With optimal tuning on a turbocharged motor though, I would put money on e85. 

[az_rat210]

To run on E85 the valve train needs to be upgraded to handle the higher burn temperatures.  E85 is a lighter molecule than gasoline, burns hotter, faster, easier (due to lower surface tension partly).  Lighter molecules reduce vibration faster than heavier molecules thus they cool off faster (lower temp out exhaust).  Because the ethanol burns faster, there is less continous power on the downstroke of the cylinder.

 

Because ethanol usually contains more oxygey molecules than gasoline allows for more H2O (water molecules) to be formed thus less pollution.  Some hyper milers claim higher mpg by adding a small amount of acetone to their gas tank to lower the surface tension of the gas allowing for better burn.

[datzenmike]

 

To run on E85 the valve train needs to be upgraded to handle the higher burn temperatures.  E85 is a lighter molecule than gasoline, burns hotter, faster, easier (due to lower surface tension partly).

 

 

Ethanol contains less energy that gasoline about half as much, so how is it going to be hotter? Never heard of valves being replaced because of this. Turbo engines can double the horse power even triple it and keep the same valves. And what would you replace them with?

 

Lighter molecules reduce vibration faster than heavier molecules thus they cool off faster (lower temp out exhaust).  Because the ethanol burns faster, there is less continous power on the downstroke of the cylinder.

 

 

Carbon dioxide from ethanol and carbon dioxide from gas would be the same size molecule so what's left? H₂O? If the exhaust is cooler, maybe there was less heat to begin with.

 

[az_rat210]

I could have sworn Ethanol burned hotter than gasoline.  A google search has corrected me of this. :confused:  So where and what path did my brain go down to day.  Ethanol can cause damage to seals on older motors not designed to handle the ethanol which can lead to motor damage.  It burns cooler but longer so a motor gets hotter but the exhaust is cooler due to the lower temperatures?  Think I will go out and lynch the Science the neuron in my head.

[datzenmike]

It will burn 'slower' in a stock low compression engine. That's why an ethanol engine build should include a 13 to 1 compression to increase the efficiency. Compression increase will also increase the burn speed. (less ignition advance) 

[DanielC]

I went to some drag boat races a few years ago, and spent a weekend there.   Some of the boats ran methanol, and even a few ran some nitromethane.   Some of these boats were running a 7 second quarter mile.

 

When they fired up the alcohol engine in the pits, they would not even bother to supply cooling water to the engine.  I asked why.

They said, in the pits you cannot run the engine hard enough to get it warm, because the alcohol to air mixture is so much more rich, that the evaporation of the alcohol sucks so much heat out of the engine.   After the run in the pits, a few would cover the engine with a blanket, to retain some heat in the engine.

[paradime]

Like I said above, there is a lot of disinformation out there about ethanol. Bare in mind though, the conditions used during combustion can yield very different thermodynamic results. There are two basic factors that cause ethanol to burn cooler than gas. First is natural cooling of alcohol during atomization. Second is a greater amount of combustion product in the mixture. While ethanol can burn cooler and produce more power, thats because we performance guys burn as much ethanol as possible to get max power. Again, it's important to delineate between performance use vs. transportation use. If you really want to geek out on this, here's a little lite reading. http://www.fisita.com/education/congress/sc10/fisita2010sco04.pdf

 

Mike said: Ethanol contains less energy that gasoline about half as much, so how is it going to be hotter? 

 

What Mike is referring to is the stored potential energy of gas vs. ethanol, but their relative thermodynamics is not as simple as that. Unlike gas, under higher compression ethanol's relative octane increases from about 90 at 9:1 to as much as 107, but it's actual power advantage is it's resistance to preignition, aka detonation. It only requires 2 degrees advance for every increase in atmosphere. It is a confusing paradox to think that something more volatile, can burn cooler and also be more stable. You read that UC Berkeley study and figure it out. Once things get beyond my ability to maintain interest, or comprehend, I chalk it up to voodoo and move on with gratitude that it works the way it does.

[Anabolic620]

Outstanding write up!!! I absolutely love e85. That's all I run in my Evo.

[Anabolic620]

It's nice to see someone deciding to take the time to research and post up findings about a growing and even more popular/cheaper fuel used widely in racing and on street. Nice!

[Anabolic620]

Thank you for this thread.

[vern_k]

nice write up, thanks. E was the main fuel for early internal combustion engines before oil was found in TX, the whole it made food prices rise is BS the food prices went up with the cost of fuel and they just did some spinning on that...... if you do the reading on it the waste, is better for animals therefore helping with food production.... and it can be made from many more things then corn.....

 

Anyways I have been using it in my 85 Maxima for years, I have found that about 1/3 E85 works well (a little rough starting in winter) with no tuning device, a little bump in power (via butt dyno) and a smother running engine and no drop in MPG. She has 230,000 and has never had major work done, tried it in a honda civic (my Xs car) and with the higher compression it was able to take a bit more but a bit over 1/2 E85 it would start having rough start up and throw CEL (no tuning device) but that would go away as soon as you dropped the E85 % down, and would run smooth once warmed up (about 1 min if cool out less if warm out) even though the CEL was on from the rough start.

 

It really helps with passing emissions, not that my Maxima would not pass with out it, but it does keep her low enough to pass for two years. One thing I do recommend if this is something you are going to do, is change your fuel filter after the first couple tanks of fuel you do this too, as mentioned E does absorb water and with that water that in your tank already is crud so as it pulls the water out of the fuel in your tank already so comes the gunk (think fuel system cleaner= Isopropyl alcohol) and with changing the fuel filter you should change the rubber lines anyway, and most fuel lines in parts stores are E85 ready anyway. So if you are looking to clean out your fuel system while getting a little more power it is a good option, each set up is going to be a bit different the best would be start adding a bit more and see how it runs once you get to the point that it's starting harder then you like back off a bit, enjoy the cheep power adder and knowing you are helping a little with keeping fuel supply domestic and pushing the company's see that it is worth going greener, by creating the demand for the product.....  

[paradime]

That's an interesting use of ethanol for sure. So the stock ECU tune on your X's Civic was able to run an almost 50/50 blend gas to e85. That's crazy. What year was it? I finally converted my car to a flex fuel system, so I can run any ratio. I've had great results.

 

Again I'm not a crusader, but I get sick of seeing all the corporate disinformation out there about ethanol. Almost half the ethanol made today is second generation production. Switch grass is a fast growing crop. Unlike wheat, it can yield up to 5 harvests per season. Plowing in the stock and root replenishes the soil, so it needs less fertilized for the next food crop. Any argument that ethanol production is harming our food supply is DOA at this point.

 

It's funny, just before the France Energy Summit, there was a big political campaign to reduce mandatory ethanol in California. Paid for by, you guessed it, big oil. The first item on the agenda in France was calling for higher ratios of renewable fuels at the pump. Then Obama stated that he is pushing for more ethanol and the stage is set for another corporate/political showdown. Opec Vs Archer Daniels Midland Co. Shit, I don't know witch corporation is worse, but they're spending millions telling the public what to think. The general public is ill informed, but if you look at the big picture, you get a much better idea of what's actually going on.

 

This may not come as a shock, but if you look at the passed year and a half, oil stocks have taken a serious beating.

 

http://www.macrotrends.net/1335/dollar-gold-and-oil-chart-last-ten-years

 

Also a years ago, the Rockefeller family sold all their holdings in oil, stating "Fossil fuel is no longer a sustainable form of energy for this planet". Symbolically speaking, this was hugely significant, because oil is where the Rockefeller family's wealth was made.

 

http://www.bbc.com/news/world-us-canada-29310475

 

Exxon is under attach for documents that suggest they knew about the effect of "green house" gas's effect on climate back in the late 70s, but withheld that information from the public, later saying the burning of fossil fuel does not effect global warming. Reminds me of when they had all those tobacco executives lined up in front of a congressional investigation committee saying, "I do not believe cigarets smoke is addictive". If history tells of anything, when it comest to public health and the environment, as long as there's money to be made, people at the top will look the other way in order to get it. 

 

http://www.thenewamerican.com/usnews/politics/item/21918-new-york-attorney-general-goes-after-exxon-mobil-on-climate-change-stance

 

Even Opec can see the writing on the wall.

 

http://www.nytimes.com/2015/12/05/business/energy-environment/opec-meeting-oil-production-price.html?ref=topics&_r=0

 

One of the fastest growing forms of investment are what is called impact investments. A firm will create a hedge fund that invests in a particular industry, or companies that fit a particular agenda such as; the hiring of Vets, Women CEO, micro lending in developing countries, and renewable energy. Banks are not lending to small companies, so another huge insularly benefit of this movement is it decentralizes capital funding of new technology. If a bank is highly invested in the status quo, there is a conflict of interest in lending to a new industry that disturbs their world order. 

[vern_k]

The civic was like a 95 I think. One down side is that I only have found one place to get it so it takes a bit of planning to go get fuel..... I do keep up on some companys that are working on stuff like this company has stuff going on http://bfreinc.com/I do hope they take off a bit better but it really sucked almost all the green companys that I own stock in, the stocks dropped when oil prices dropped, one of those oh hey it's cheep again so I don't care about other things that would be better in the long run. There is a show on netflix that had a bunch of the story and it's called "Pump" and it had stuff like when CA was going to demand more E in the gas that the companys just started using a additive and said it did the same thing..... 

 

My project car is going to be tunable so I will be able to get it tuned to run E85, one of the reasons I don't want to drop CR to much for turbo, but still want to keep it down to run turbo and 91 oct for when I can't get E85, but should get one of the E content detectors I know there are a few out there. Have thought about putting a cold start system using propane for if I'm in a place where it gets really cold and such.   

  

[paradime]

I used the Zeitronix Ethanol Content Analyzer kit. Real time display of fuel ethanol content, and fuel temp ranging from -40 to 125 °F (-40 to 52 °C),This helps in programing for cold starts. Has two analog outputs so you can run separate data logging and engine management systems. The actual fuel sensor's output is digital, so they use a module to converts it to voltage output, so the ECU can understand it.

 

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

 

If you go this route, be prepared to do some serious programing and dyno time. Most stand alone ECU manufacturers have a downloadable flex fuel firmware update that provides the basic algorithm and interface for the data input. Programing the ECU to modify the entire tune on a ration continuum is WAY above my pay scale. If you're not a master tuner with your own dyno, it's not for the faint of wallet. I kind of combined two tune upgrades into one session. After rebuilding my head, I wanted to push boost some more, and I made the jump to ethanol at the same time. I had my car done by Bryan at Rebello racing and as usual he hooked it up right. Mild tune on 91 oct pump gas at about 12psi. On e85 it's running 15psi, and the timing and fuel curves are much more aggressive. Ethanol might as well be heroin, cuz brother, I'm addicted to that power.

[vern_k]

will have to price that out, don't think I will be able to intergrat it into my ECU since I'm going to be running a factory with UpRev Osiris, with a cut down harness and NATS removed (ok thats what I ordered but since the rest of the stuff I bought from Fever Racing has seem to be not that great I will see how much work it is going to be to make it work) but if I can get it all to work with a way to switch maps with out getting out the lap top, I should be able to have a map for 91 oct and maybe a couple for different % of E 

 

 

I have thought about putting my Maxima on the dyno just to see what a 230,000 mile VG30E puts out, then do my mixed fuel in and see what gains/losses I really get, but thats for sometime when I feel rich.....