E85 ethonal tuning

[halfachance]

so can i make my 03 avalanche run on e85 and if so can i tune it to haul balls

[stevebo17]

you have to get this weird kit for it I think its a filter and some other crap to make it run right. I don't really like the stuff myself,it always has lower numbers than with "real" gas. With a tune though I'm not sure...

[EC_Tune]

You have to get the L59 engine's fuel composition sensor, plumb/wire it into your truck and then get an L59 engine calibration as well as the injectors. Then you're good to go.

If you were to run E85 exclusively, look at an L59 flex fuel cal in the tune repository as a comparison.

EC

[halfachance]

well i didnt know its 110 octane so i can push more boost and the engine runs cooler sounds like a plus to me but is this just a fad or is it here to stay

[samgm2]

well i didnt know its 110 octane so i can push more boost and the engine runs cooler sounds like a plus to me but is this just a fad or is it here to stay

Ethanol has lower energy content than iso-octane. It has a stoichiometric ratio of about 9 as opposed to 14.7 for gasoline.

It takes more ethanol to make the same power. The fact that it has a higher octane number has nothing to do with power. "Octane rating" refers to the ability of a fuel to burn slower and thus reduce the risk of knock (a reaction with occurs faster than the speed of sound in side your combustion chamber). The standard for octane rating is ISO-OCTANE (the primary ingredient in gasoline). ISO-OCTANE is defined to have an octane rating of 100.

The higher the octane rating, the slower the reaction rate and thus the velocity of the flame front. Since you are after making the maximum pressure when the cylinder is at TDC, you want to time the reaction for complete combusion when it is at TDC WITHOUT a supersonic reaction rate.

Unless tuned for the higher octane fuel, an engine will produce less power than the same engine tuned for the lower octane fuel. If higher octane fuel is put into an engine tuned for a lower octane fuel, then the combustion will not be completed until the piston is on its way down.

F = Pressure times area. Since the piston will be further down when reaction has completed, it will be in a larger volume and hence have lower pressure. This means the force on the piston will be lower and thus produce less power and result in lower efficiency for a given quantity of fuel.

Unless your truck was designed to run on ethanol and has larger injectors. It is unlikely, that stock injectors could flow enough ethanol to compensate for the lower energy value of ethanol and make the same power as the gasoline tune. It just depends on how close to maximum duty cycle the injectors run and if they could be pushed another 35-40 %.

You may need larger injectors to flow more ethanol in order to compensate. You will have lower fuel economy (on a volumetric basis (per gallon)).

That aside, burning ethanol has a zero impact on the environment in terms of adding CO2. During the growth cycle of the plant, it absorbs CO2 from the environment. When burned it releases it. Zero impact. Within a decade cars will run on biofuels in order to solve the problem of CO2 emissions. You are just getting a head start.

Sam

[halfachance]

true but its just like running alchol themotor temp is way cooler and i should be able to push more boost

[TheDarkKnight]

Ethanol has lower energy content than iso-octane. It has a stoichiometric ratio of about 9 as opposed to 14.7 for gasoline. It takes more ethanol to make the same power.

Which can be more than made up for depending on the application. The higher the load, the better a well-done E85 egine will perform. A pure E85 engine has the capacity to make better fuel eocnomy than gasoline. Why? It extracts more energy from the fuel. So it may take more fuel to make the same power, but depending on the application it may take less.

Studies have been done where small diesel engines were "converted" to ethanol and methanol. The compression ratio was about 29-24:1. Yes, turboed. Both produced better fuel eocnomy (same car, same engine just fuel differences) than the diesel, which was better than the gasoline engine for the same car. The difference was a bit larger than the difference from gasoline to diesel. The big difference is compression.

The fact that it has a higher octane number has nothing to do with power. "Octane rating" refers to the ability of a fuel to burn slower and thus reduce the risk of knock (a reaction with occurs faster than the speed of sound in side your combustion chamber). The standard for octane rating is ISO-OCTANE (the primary ingredient in gasoline). ISO-OCTANE is defined to have an octane rating of 100.

The higher the octane rating, the slower the reaction rate and thus the velocity of the flame front. Since you are after making the maximum pressure when the cylinder is at TDC, you want to time the reaction for complete combusion when it is at TDC WITHOUT a supersonic reaction rate.

This is important, bit there is anotehr aspect to it as well. The "energy content" of gasoline or ethanol refers specifically to it's heat absorption capacity. The less it can absorb, the higher the rating. Ethanol burns cooler and due to it's properties absorbs less heat.

That said, this process is not tested using and IC engine. When you burn the fuel "in atmo", it behaves one way. Under short timeframes and compression it acts differently. In this case specifically, in the short timeframe of a cylinder, the ethanol does not have the time needed to absorb it's heat capacity. As a result, the "energy content" is higher. Yes I kow how wierd that sounds at first blush, but if you stop and consider it it'll make sense.

But dont merely take my word for it. The Saab Biopower, which is an E100-G100 flex fuel (pure ethanol to pure gasoline) gets 15% better fuel economy on the highway on E100 than it does on G100. This year I understand they hybridized it to boot.

So the claim of lower fuel eocnomy must carry caveats to be accurate. And no you can't take EPA lsitings at face value on this. They don't test it, they take the "gasoline' (they don't use it) calulations and appy a .33 reduction "due to lower energy content". Take them with a huge grain of salt, if at all.

F = Pressure times area. Since the piston will be further down when reaction has completed, it will be in a larger volume and hence have lower pressure. This means the force on the piston will be lower and thus produce less power and result in lower efficiency for a given quantity of fuel.

All true again. However, an additional factor to consider is the ability to run higher compression - a big win for ethanol. Additionally ethanol contains water which increases slightly the pressure. Also a plus as "old timers" will talk about. Water "expands more" and does it faster, this "filling up" the cylinder and increasing force by increasing pressure, albeit slightly.

Unless your truck was designed to run on ethanol and has larger injectors. It is unlikely, that stock injectors could flow enough ethanol to compensate for the lower energy value of ethanol and make the same power as the gasoline tune. It just depends on how close to maximum duty cycle the injectors run and if they could be pushed another 35-40 %.

My previous alcohol experience is on carbuerated engines, so ic an't speak specifically to injector sizing. However, with good tuning carbuerated E85 vehicles (100 even) have been shown to run quite well with only small increases in jet sizes - as low as 14%. in this case the fuel eocnomy was only slightly lower (single digit percentages here folks). However, under load (such as a 1/2T pickup with a load in the bed) it produced better MPGf than the same vehicle running on gasoline.

You may need larger injectors to flow more ethanol in order to compensate. You will have lower fuel economy (on a volumetric basis (per gallon)).

Likely true, though again it depends on usage and load application. And if you've got "the right stuff" to experiment. That said my 04 Suburban - entirely untuned and from what I hear not tuned at all for E85 (just a change in stoch)- gets in-town MPGg of about 12-14, and MPGe of 9.5-12. Freeway numbers I have but they are not comparable due to significant terrain and fuel base differences.

As you can see if I can pick up one or two MPGe I'll be very close and occasionally better than my in-town MPGg. At least until the turbo gets installed.

That aside, burning ethanol has a zero impact on the environment in terms of adding CO2. During the growth cycle of the plant, it absorbs CO2 from the environment. When burned it releases it. Zero impact.

Not quite, but we are getting there. The problem lies in the way E plants are done. They use NG with a few (2-4) exceptions which use coal. Both of those release CO2 that is not consumed by growing the plants. it depends heavily on the feedstock. Here I've referenced corn, the most common in the US (only).

Newer techniques and other feedstocks actually reach a point where more carbon is consumed than is released. Will we someday be needing to increase our CO2 production?

Also, I'm currently working on a ethanol plant design that uses solar thermal power in place of more than 70% of the current natural gas/coal input. Ethanol conversion is primarily a heat consumer, comparatively little electricity. Not only would this reduce one of the single largest and costly consumables in the ethanol production process, it will further reduce net emissions.

That said, the E85 powered Suburban puts less net CO2 in the air than a Prius, burns less "fossil fuel" and far less petroleum - "well to wheels". All on a per-mile basis. Gotta love that.

Within a decade cars will run on biofuels in order to solve the problem of CO2 emissions. You are just getting a head start.
Sam

It will solve many more problems than the alleged CO2 concern. I'm considering fully converting the Vette to E85 in the next couple years. I

Once I get the Vette dialed in, I intend to set my sights on the Suburban. I'm, very happy to see more and more E85 uningrelated questions and posts here. I should be contributing some direct HPTuner+E85 experience over the winter.

Now back to the original poster ... You might want to verify that your fuel lines and tank are E85 compatible. They should be if the model you have had an E85 option - makes sense to just use one physical set. But given the risk it's well worht verifying. Also, if you've been running gasoline for a while be careful. Ethanol will clean your tank and lines. So be prepared for several frequent fuel filter changes in the early days.

Cheers,
Bill

[Runn WS7]

I´ve been running my car on 100% E85 for two years... Car feels alot stronger on E85.

[TheDarkKnight]

I´ve been running my car on 100% E85 for two years... Car feels alot stronger on E85.

My wife says the burb feels sluggish when she has to run gasoline.

[SS_bnoon_SS]

I´ve been running my car on 100% E85 for two years... Car feels alot stronger on E85.

Do you have anything to contribute as far as what you've changed in your tune to do so? I'm on the fence about E85 because I travel so much, but since the E85 stations are popping up more and more, I'm getting closer to doing so on a regular basis. I drive 25,000 miles a year, so it's important to be able to find the right gas if I were to switch.I have done some experiments to see what I'd need to change to tune it in... One question that has come up: What to do about o2 seonsors? Since stoich is around 9:1 instead of 14:1, shouldn't we need to switch to another o2???

[samgm2]

This is important, bit there is anotehr aspect to it as well. The "energy content" of gasoline or ethanol refers specifically to it's heat absorption capacity. The less it can absorb, the higher the rating. Ethanol burns cooler and due to it's properties absorbs less heat.

The octane rating has almost nothing to do with heat capacity and nearly everything to do with the "rate of reaction." The heat capacity of liquids is very small compared to the heat of combustion.

A pure E85 engine has the capacity to make better fuel eocnomy than gasoline. Why? It extracts more energy from the fuel. So it may take more fuel to make the same power, but depending on the application it may take less.

You seem to be contradicting yourself. It is HEAT that makes your car move. You start with heat and convert a small portion of it to work. If you are saying that because of the slower burn rate of the ethanol that you are able to affect a higher efficiency. That may be true for a different engine, but in this case you are running the fuel in the same engine. It is unlikely you could change the efficiency very much in an engine designed to run gasoline. Compression ratio is wrong, valve timing, etc. To get the same power, you will have to burn more gallons of the lower energy fuel.

Studies have been done where small diesel engines were "converted" to ethanol and methanol. The compression ratio was about 29-24:1. Yes, turboed. Both produced better fuel eocnomy (same car, same engine just fuel differences) than the diesel, which was better than the gasoline engine for the same car.

I have no problem accepting that the diesel cycle is more efficient than the otto cycle. But we aren't talking about the diesel cycle here. We are talking about a gasoline engine. These are standard chevy blocks running the otto cycle.

That said, this process is not tested using and IC engine. When you burn the fuel "in atmo", it behaves one way. Under short timeframes and compression it acts differently. In this case specifically, in the short timeframe of a cylinder, the ethanol does not have the time needed to absorb it's heat capacity. As a result, the "energy content" is higher. Yes I kow how wierd that sounds at first blush, but if you stop and consider it it'll make sense.

None of that makes any sense. The heat capacity of isooctane, and ethanol are both negligible compared to their heats of combustion. Moreover, before combustion even takes place a phase change will have to take place. Meaning that the heat capacity will play a role (albeit very small) until the fuel can get to its boiling point and a phase change takes place. Even the heat of vaporization will play a very small role and this is larger than heat capacity. So I have NO IDEA what you are talking about in terms of how the fuel behaves under short time frames. You aren't stating that a LIQUID burns are you? If not, then how do you suppose it goes from a liquid to a vapor without the heat capacity being involved. In any case, compared to the heat of combustion, heat capacity, heat of vaporization, can all be ignored. They have less than a 1% impact combined. I am happy to pull out Perry's Handbook and get numbers, but I suspect you know I am right.

All true again. However, an additional factor to consider is the ability to run higher compression - a big win for ethanol. Additionally ethanol contains water which increases slightly the pressure. Also a plus as "old timers" will talk about. Water "expands more" and does it faster, this "filling up" the cylinder and increasing force by increasing pressure, albeit slightly.

Old timers??? Higher compression??? None of that matters. The only thing that matters is that you have to have the highest pressure at top dead center in order to make the most power. Gasoline engines generate between 2500 and 3000 PSI at TDC. Whether you start at 140 PSI or 200 PSI has little impact on final pressure and more impact on the velocity of the flame front (rate of reaction). Ethanol has a lower rate of reaction. In order to maximize pressure you have to adjust timing so that the reaction is complete by the time the piston is at TDC. In order to have the highest final pressures, you either have to have a higher temperature or you have to burn more moles of fuel and air. In a naturally aspirated car, the second is not an option - you can only take in so much air and thus, only burn so much fuel. As for higher temperatures, ethanol loses here too. Yes trace amounts of water will vaporize and turn into steam at a cost of lower temperatures. But high temperatures are what create the highest pressures. The higher the pressure without detonation, the more efficient the otto cycle is.

I admit that all of my calculations are carried out via ideal gas law derivations: T2/T1 = (P1/P2)^R/Cp So if this discussion goes any further maybe I should look at modeling via Peng-Robinson EOS...

However, under load (such as a 1/2T pickup with a load in the bed) it produced better MPGf than the same vehicle run...

Anectdotal evidence about mileage in your experience is meaningless. I can drive the same car you drive and if I am conscious of my mileage will get better mileage than you do on any given day.

I have a Miata that I put an LS6 into. I get mileage that varies from nearly 40 MPG to as little as 14 MPG. Even with the same fuel I get that kind of mileage variation.

I have also run e85. My results showed a drop in mileage of about 35%. Moreover, I made considerably less power on a dyno - also about 35% less.

Thermodynamicly, ethanol is just not there. Having said that, gasoline is NOT a long term option. ETHANOL IS IN OUR FUTURE. I agree we can get the power with ethanol but it will take more of the fuel to do so or possibly a different engine. If you have a new engine that manages to take advantage of the specific charateristics of ethanol and manages to change efficiency to something better than that of an otto cycle, I would be very interested in studying it.

In any case, you made some good points and we agree that ethanol will play a significant role in the future.

Sam

[Runn WS7]

You´ve seen this thread? http://www.hptuners.com/forum/showthread.php?t=9389

[n0dih]

According to Ford, E85 makes 3-5% (conservatively speaking too I have read) more hp than gasoline at almost any given rpm/condition.

Why? Lets see, it has less BTU's, takes more of it to do the same work, how on earth could it make more power? Jeepers Batman, he is confusing me!

Well, simple. There is more O2 available in the E85 A/F mix than gasoline, so there is more a complete burn, so more of the fuel that is in the chamber is consumed and therefore makes more hp than the same cyl fill of gasoline.

Basic physics says we must have an oxidizer to make something burn. More oxidizer, hotter burn. So we actually could be making more cyl pressure (if we make more HP we must be) with E85 than gasoline. This is why Nitrous works so well.

So yes, if you are going to the track and have larger injectors to handle it, by all means, run E85. It is back to being $0.55 a gallon CHEAPER to run E85 over gas here, so my cars are back on a corny diet again.

Even think I have my cold start issue with E85 fixed, it started great this morning. Finally! Factory drivability on E85 for a 217K mile LT1 running OBD1....

...
Unless tuned for the higher octane fuel, an engine will produce less power than the same engine tuned for the lower octane fuel. If higher octane fuel is put into an engine tuned for a lower octane fuel, then the combustion will not be completed until the piston is on its way down.....

Is E85 the answer to our fueling issues? No, I don't think so. But it can be viable, so for now, I will run it when it becomes feasable to do so. WS7 is definately saving a lot of $$ by running it with his fuel prices! I only pay $1.97 to $2.33 for a gallon of E85 as of March 2007 across my whole area. Gas is at $2.599 as of today.

[Runn WS7]

I had some coldstartproblems until i raised the cranking fuel way up.

[n0dih]

I took all my prime pulses and x1.5 and it starts like gas now. I am quite pleased.