E85, IS It Plant Juice Power, Or Fuel System Eating Acid From Hell

[paradime]

A few years ago I posted this on another site, and I thought I'd bring it here. I've been running e85 for 4 years now, and can say with conviction, the shit works.

 

I'd spent months researching e85 before making the decision to build my SR swapped 510's fuel system to be able to run this fuel if I wanted. When I posted this in my build thread on the Realm 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 was from guys in Australia who'd been using e85 for years.

 

In the interest of our new Ratsun 2.0 nonpolitical act, I'll define the conversation 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 renewable fuel it's somehow subversive. These same 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 shit ton 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 pro renewable fuel 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. I realize there is a disconnect between the broader market'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 the only thing he's looking for is 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, to JQP what's the point?

 

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 becomes more efficiently 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 these two 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 coming from hackers who didn't know what they were talking about. Yes, If you don't do it right, as with any fuel, it will bit 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, efficiency 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 PE 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 PE is also one of the reasons why e85 burns cleaner, because more of it's energy is converted during combustion.

 

"Because Ethanol contains oxygen, it has a very low power stoichiometric
when compared to gasoline fuels (6.5 compared to 12.5). Ethanol must be run at much richer
mixtures than gasoline, more than offsetting the lower energy per unit volume. The net
energy released per cycle is higher and this results in more horsepower."

http://iqlearningsystems.com/ethanol/downloads/Racing%20Fuel%20Characteristics.pdf

 

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

 

https://www.sae.org/publications/technical-papers/content/2007-01-0473/

 

 

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.

 

Ethanol has a very high MON octane rating, allowing engine
builders to run higher compression ratios without fears of destructive detonation. It also has
a very high Latent Heat of Vaporization, so the engine is cooled far better than one running
on gasoline. This lowers bottom end and oiling system temperatures substantially.

 

3. Zero carbon build up.
Shit, that ones self expiatory.

 

4. Average price per gallon is still around $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
http://www-personal.umich.edu/~annastef/papers_FFV/DSCC08_KAhn_Stefanopoulou_Jankovic.pdf

 

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

[KoHeartsGPA]

This is interesting, would the KA24e with the 240sx ECU + harness be compatible for this option?

[paradime]

Hey KO,

 

In short, no not so much. Without forced induction, or NA with super high compression, ethanol doesn't make much sense. You won't get to a 107 oct without higher combustion pressure. Not having a tunable ECU is also a drawback, but there are other considerations like fuel pressure, replacing all rubber in the fuel system, injector size, etc. There are re-flashes to convert the KA to run e85 you can jet off the internet, but that's a highway to nowhere when you consider the variables of engine mods, true gas/ethanol ratios, on and on. 

[KoHeartsGPA]

Hey KO,

 

In short, no not so much. Without forced induction, or NA with super high compression, ethanol doesn't make much sense. You won't get to a 107 oct without higher combustion pressure. Not having a tunable ECU is also a drawback, but there are other considerations like fuel pressure, replacing all rubber in the fuel system, injector size, etc. There are re-flashes to convert the KA to run e85 you can jet off the internet, but that's a highway to nowhere when you consider the variables of engine mods, true gas/ethanol ratios, on and on.

 

Yeah I see, might just go with a compatible option rather than attempting to retrofit the KA.... thanks for the heads up ;)

[G-Duax]

Many modern fuel lines are E85 compatible, so no real reason to go to Teflon lined hose.

 

Paradime, any timing ball park numbers on timing curves for E85 vs. gas ?

 

I will be running larger injectors, but my stand alone does sequential injection, so I can start spraying fuel just as the valve opens, and shut off the fuel before it closes.

 

If I had a choice, I'd rather run 100% methanol.

But it would be expensive to change over the whole fuel system on a car to run it.

It really does attack aluminum, so things like fuel rails would be a problem.

On race engines, the fuel system is purged at the end of race day.

Not something you want to be doing on a daily driver.

[paradime]

Many modern fuel lines are E85 compatible, so no real reason to go to Teflon lined hose.

 

Paradime, any timing ball park numbers on timing curves for E85 vs. gas ?

 

I will be running larger injectors, but my stand alone does sequential injection, so I can start spraying fuel just as the valve opens, and shut off the fuel before it closes.

 

If I had a choice, I'd rather run 100% methanol.

But it would be expensive to change over the whole fuel system on a car to run it.

It really does attack aluminum, so things like fuel rails would be a problem.

On race engines, the fuel system is purged at the end of race day.

Not something you want to be doing on a daily driver.

 

Timing advance is really dependent on compression and or boost, and it's based on a map curve. For higher boost applications it's not uncommon to advance 10 to 12 degrees, way more than pump gas, but again, you really need a dyno and a seriously accurate 02 sensor, knock sensor to do it right. 

[Lockleaf]

Engine masters on motor trend on demand recently did a comparison episode on race gas vs e85 that was pretty interesting. They give much of the same information you have Paradime. Yes it can be good, but like anything, it's just one more tool that is best used in specific conditions.

[nl320what]

I think E100 should have taken off as a primary fuel by now due to it being made locally easily too.

 

But it is Corn Liquor-white lightning, just like how its made from a stihl at home.

 

There use to be a solar pump that makes E100 over a couple days with just sugar and water you add to it at home processor and it was very expensive though.

 

Ethanol is hygroscopic and becomes acidic, but engines have to be made for it to take advantage of its benefits.

 

It has properties of a Diesel fuel and Gas, the Ethanol  though has a Cooling effect in the combustion, and allow you to run a smaller exhaust valve and enlarge the intake valve actually.

 

Just for giggles I ran E85 in my 67 Bug stock everything, it runs but needs tuning the jets.

[KoHeartsGPA]

I know this doesn't cover everything....but....its fun to watch experiment...

 

[paradime]

^ "Moonshine, being ethanol burns a lot hotter than gasoline." Cute, but Stupid. 

[G-Duax]

I did find some info that E85 requires more initial advance, and less mechanical advance.

Otherwise it's hard to get a good idle.

Instead of say for reference 10* initial, it has to be 20*, and then only about 10* mechanical.

Just about opposite of what you would run for gas.

[nl320what]

^ "Moonshine, being ethanol burns a lot hotter than gasoline." Cute, but Stupid. 

Ethanol has less energy content then gas so it burns cooler as a fuel if properly tuned for it.

 

If not tuned for it, just like gas it will lean out the mixture and a regular motor will naturally overheat being out of Stoic.

 

Plus there is timing and intake/exhuast diameters to accomodate the more flow required for Ethanol.

 

Again the Ethanol takes on characteristics of a Diesel and Gas fuels.

 

Overseas they have been running Ethanol 100% since the early 70's and also the Ford Model T had an adjustable jet to run on the homeade Ethanol corn fuel too.

 

Its a highly miss-understood and under-developed fuel in the US.

[paradime]

There is immense money and power derived from fossil fuel energy. Because of that there are huge financial interests making sure ethanol remains miss-understood and under-developed. Seriously though, there is no way ethanol could ever replace fossil fuels, but the auto industry is moving towards electric and smaller turbocharged engines. If that is the way of the future, I would think the accessibility of ethanol should be developed as a supplemental alternative for modern turbo-ed cars.

 

For a while there in the early 2000s, there were a bunch of neo-hippies converting their old turbo diesel 240Ds to vegetable oil, and getting it from recycled restaurant fryer grease. All well and good until you wake up on a cold morning and your fuel has solidified in the lines. One cold winter and you don't see'm around any more.

 

Oil money and power interests aside, ethanol is a great performance fuel in the right applications, and that's what I'm interested in. Until gas goes back above $4.00 a gallon, for the masses ethanol will remain fringe hippy shit, and thats fine by me.

[G-Duax]

For a while there in the early 2000s, there were a bunch of neo-hippies converting their old turbo diesel 240Ds to vegetable oil,

 

I read up on the conversion a little once, and the witch's brew of chemicals they were mixing, and heating in old hot water heaters to make the junk was scary.

One guy down here burned his house down trying to make 'cheap' diesel. 

[nl320what]

I have tuned a 05 Dodge SRT4 (Neon on Speed), 2.4L turbo 4cyl...... tastefully thought out upgrades as far as rerouted turbofold, 1200cc Siemens Injectors, fuel pump mod, wide band O2, and handheld DSP tuner.

 

We tuned it for dual fuel, not on the fly but had a 93 Octane Gas tune and E85 tune.

 

Gas Tune made 350hp and was consistent and fun.

E85 Tune made 420hp and was inconsistent due to the blends which is E70  to E90 really.

 

E85 ran much cooler after driving it hard, plus you can litterally suck on the tailpipe and its just water and a ever so slight alcohol smell.

 

But it eventually ate up the fuel sending unit like a diesel would after a year or so.

 

But you have to redesign the motor from scratch and tune it way differently, 

[paradime]

I read up on the conversion a little once, and the witch's brew of chemicals they were mixing, and heating in old hot water heaters to make the junk was scary.

One guy down here burned his house down trying to make 'cheap' diesel. 

 

Here in cali they were running straight veggie oil with a simple stabilizer and two stage filter. Hippies  :rolleyes:

 

 

 

I have tuned a 05 Dodge SRT4 (Neon on Speed), 2.4L turbo 4cyl...... tastefully thought out upgrades as far as rerouted turbofold, 1200cc Siemens Injectors, fuel pump mod, wide band O2, and handheld DSP tuner.

 

We tuned it for dual fuel, not on the fly but had a 93 Octane Gas tune and E85 tune.

 

Gas Tune made 350hp and was consistent and fun.

E85 Tune made 420hp and was inconsistent due to the blends which is E70  to E90 really.

 

E85 ran much cooler after driving it hard, plus you can litterally suck on the tailpipe and its just water and a ever so slight alcohol smell.

 

But it eventually ate up the fuel sending unit like a diesel would after a year or so.

 

But you have to redesign the motor from scratch and tune it way differently, 

 

That Neon sounds interesting. I don't know about redesigning the entire engine, but it really helps having a flex fuel sensor, voltage sending unit, and a stand alone programable ECU to map for any E/G ratio. I have that set up in my SR 510 and it's making consistently fun 300hp to the wheels on the e85 here. With the right cam I'm sure it would make more, but there's a fine line between fun and terror. If anything I'd like that SRT4's extra 0.4L for a bit more low end grunt. 

[nl320what]

Here in cali they were running straight veggie oil with a :rolleyes: simple stabilizer and two stage filter. Hippies  :rolleyes:

 

 

 

 

That Neon sounds interesting. I don't know about redesigning the entire engine, but it really helps having a flex fuel sensor, voltage sending unit, and a stand alone programable ECU to map for any E/G ratio. I have that set up in my SR 510 and it's making consistently fun 300hp to the wheels on the e85 here. With the right cam I'm sure it would make more, but there's a fine line between fun and terror. If anything I'd like that SRT4's extra 0.4L for a bit more low end grunt. 

I have ran SVO and filtered WVO and BioD in my old Mercedes 240D and 300D cars, warm weathers above 60degs you can run it without tank heaters and no need for cetane boosters, just occationally change canister fuel filter and run diesel clean to prevent build up.

 

03-05 Neon SRT4 cars were the best bang for your buck fun car, didnt even have VVT or anything complicated.  Also they were 4 bolt main blocks and have gone over 1000hp with all stock internals. They blow when going lean just like any turbo car.

 

They usually go for $6000 for a mildly upgraded car.

 

E85 on a turbo just means more boost and timing curve mapping.

 

E85 on a NA motor means you can redesign it as a high compression 12:1+ motor and remap the timing for it up to a certain point.

[paradime]

I did a little research on the SRT4 and it sounds pretty stout. 1000HP on stock internals though, :w00t: holy F'n shit. Would it make a good candidate for a Dat swap? One thing I'm not so psyched on is 6200 rpm limit. Kind of like the KA24DET in that respect. The longer you can get the motor to wind up, the more access you have to power. rarely do you get loads of torque and high revving in a 4 cylinder without VVT, or stroking. Short of stuffing a flat crank V8 or a V12 into a 510, I'll stick with my SR20.  :lol:

 

 

Actually at 1 bar of boost you're essentially getting twice as much mixture into the combustion chamber. Using ethanol with higher relative compression from forced induction, there is a significant increase in it's MON octane rating, from 93 to upwards of 107 octane. It also has greater resistance to detonation than 110 oct race gas giving more access to it's stored potential energy. Ethanol also burns much cooler at base optimal tune due to it's high latent heat of vaporization and 30% richer mixture compared to gas. Every bit of change in the G to E ratio, or increase in boost starts to get complex because it doesn't equate to a linear reciprocity curve in the timing and fuel mixture. You can make gross estimates to get you in the ball park, but that's not going to cut it at WFO. The ECU monitors throttle position relative to rpm, regulates boost pressure while monitoring MAF, intake temp, fuel ratio, and exhaust 02 to adjust optimal timing, and fuel mixture accordingly on the fly. Tuning all that shit is WAY above my pay scale.

[nl320what]

I did a little research on the SRT4 and it sounds pretty stout. 1000HP on stock internals though, :w00t: holy F'n shit. Would it make a good candidate for a Dat swap? One thing I'm not so psyched on is 6200 rpm limit. Kind of like the KA24DET in that respect. The longer you can get the motor to wind up, the more access you have to power. rarely do you get loads of torque and high revving in a 4 cylinder without VVT, or stroking. Short of stuffing a flat crank V8 or a V12 into a 510, I'll stick with my SR20.  :lol:

 

 

Actually at 1 bar of boost you're essentially getting twice as much mixture into the combustion chamber. Using ethanol with higher relative compression from forced induction, there is a significant increase in it's MON octane rating, from 93 to upwards of 107 octane. It also has greater resistance to detonation than 110 oct race gas giving more access to it's stored potential energy. Ethanol also burns much cooler at base optimal tune due to it's high latent heat of vaporization and 30% richer mixture compared to gas. Every bit of change in the G to E ratio, or increase in boost starts to get complex because it doesn't equate to a linear reciprocity curve in the timing and fuel mixture. You can make gross estimates to get you in the ball park, but that's not going to cut it at WFO. The ECU monitors throttle position relative to rpm, regulates boost pressure while monitoring MAF, intake temp, fuel ratio, and exhaust 02 to adjust optimal timing, and fuel mixture accordingly on the fly. Tuning all that shit is WAY above my pay scale.

Being a larger 4cyl it does have its RPM limited and also due to that fact it has a chain driven balance shaft that help keep drivetrain from shaking itself loose.

 

But also it doesnt need to spin up to 8K to make power, it come right in with no lag and its flat torque from 2K to 6500rpm.

 

I have driven and owned alot of cars, Saturn Ion Redline, SRT4, SRT8, Nissan 350Z, and tons of american V8s making 500hp and the SRT4 has been the most fun on a budget.

 

It still gets 31mpg on gas and 25mpg on E85 at the current performance tunes, much better than my friend WRX at lower power levels.

 

Again though, the SRT4 block has 4 bolt main girdles and super high nickle blocks, its a beast in disguise.

[nl320what]

To stay on topic, E100 is a sustainable fuel that could be made at home cheap and legally with corn mash, fabbed up still, and a propane/nat gas deep fryer setup.

 

Its much easier than BioDiesel which requires more equipment, starting oil, precise mixtures, methane, lye, and heat.  You do end up with a biofuel and glycerin byproduct for homeade soaps.

[G-Duax]

How much corn by weight, does it take to make a gallon of ethanol?

How many times do you have to run it through a still to get all the water out?

How many gallons of mash do you have to ferment, then cook off to make 10 gallons of ethanol?

How much energy does it take to distill pure ethanol?

And how long does it take to make a batch, from mixing, to usable fuel?

[metalmonkey47]

I love E85, but I hate it at the same time.

 

Great for squeezing a bit more power, especially from forced induction cars but the drop in fuel economy, lack of supply and its corrosiveness make it sucky to use.

[paradime]

How much corn by weight, does it take to make a gallon of ethanol?

How many times do you have to run it through a still to get all the water out?

How many gallons of mash do you have to ferment, then cook off to make 10 gallons of ethanol?

And how long does it take to make a batch, from mixing, to usable fuel?

 

All good question's, and although there are environmental, anti-establishment, and accessibility advantages, these topics run into theoretical arguments around economics energy dependance and eco-science which are inherently political. In the interest of avoiding an intervention from Sheriff Mike, let's not go there. This thread isn't about overthrowing a F'ed up system, the topic at hand is clearing up disinformation about ethanol's viability as a performance fuel alternative to race gas in high relative compression applications. 

[paradime]

I love E85, but I hate it at the same time.

 

Great for squeezing a bit more power, especially from forced induction cars but the drop in fuel economy, lack of supply and its corrosiveness make it sucky to use.

 

Have you used it? If so what on?

[G-Duax]

I'm still waiting for nl320 to answer the questions I asked about making your own E100.......