smartman__007

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I was wondering about tuning for ethanol in an originally LO3 powered Firebird. It was swapped for a GMPP Crate Engine 350 HO. In theory I should be able to tune for regular gasoline and change some constants and maybe some fine tuning to get it perfect? I was wondering what constants should be changed besides the obvious Stoich setting.

Ronny

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how much ethanol? here is Wisconsin I can buy 10% 20% and E85.

I also changed the switch points in bin a bit higher for 10%. I am commanded to 14.3 for stoich.

smartman__007

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85%. Our state, (SD) for some reason stopped supplying ethanol above 10% because it wasn't approved in all vehicles. I've got 3 friends that all switched over to 85%. One is a carbed 383 stroker, 502 Ram Jet, and an LS1 with a super charger. It shouldn't be tough besides getting the fuel supply but it's only a 330 HP motor. If this works well I plan on switching my LO3 Camaro over as well. Up the pressure and change some constants and off I go.

Ronny

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a wide band would be a good idea.

smartman__007

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Definitely for WOT with the Ethanol. It's a pain as is with a NB and Gasoline. The main question is which constants affect the fueling. I think I hit them all. Here is a list of what I changed.
Constants/Scalars
CldLp - Stoich AFR
CldLp - Idle AFR
OpnLp - Idle AFR
OpnLp - Max lean AFR
Tables/Functions
PE - WOT Air Fuel Ration Vs. RPM
Crank - Air Fuel Ration Vs. Engine Temp
OpnLp - Open Loop AFR vs Engine Temp
OpnLp - Open Loop AFR vs Engine Load
Choke - AFR subtracted vs Coolant
HiWy - Highway AFR Vs. Load

Anything I missed for changing Fuels?

smartman__007

iTrader: (1)

Anyone?

Grim Reaper

Regarding Ethanol, it's HIGHLY CORROSIVE! That is why you need to upgrade your entire fuel system if you run more than 10% (fuel tank, special pump, fuel lines, fuel rails & injectors all need to be upgraded). Ethanol eats the metal and the gaskets.

Tuning wise, you obtain less energy per gallon of ethanol than gasoline but ethanol has a higher octane rating (ie. it burns slower). Therefore you need more timing and compression for ethanol than gasoline. Again, that is why you vehicle needs to be designed for ethanol if you plan to run more than 10%.

Overall, ethanol is a big lie and complete ludicracy. It is all about politics with litte thought into the real costs. It takes more overall energy to produce ethanol than gasoline. People think "corn" but forget the energy needed to power the equipment and transport. Ethanol is so corrosive that you must transport it in special trucks instead of pipelines.

But, now the truth about ethanol is coming out and people are now realizing that it is a stupid move. Without subsides, the price of E85 will cost more than an equivalent gallon of gasoline.

smartman__007

iTrader: (1)

I always thought that Methanol was HIGHLY corrosive, and that ethanol while still not as nice as gasoline, would not eat parts like methanol would. Ethanol is going to be around here (SD) for a while with all of the government.

With the higher octane rating we were planning on running more timing and higher compression. What I was wondering is if it is just as easy as changing some variables in the prom to account for the ethanol? On the tuning side of things if it would be able to change to ethanol then go back to gasoline depending on the situation.

Grim Reaper

It really depends on the concentration of ethanol. Many gasolines already contain some ethanol upto 10% (whether people know it or not) and can run "as is" (though if you run it all the time, you may wish to see if you can run a little extra timing).

However, if you want to run E85, other than maybe using the Knock Sensor to automatically pull timing out, you pretty much need to swap memcals/bin or use a larger flash prom and stack multiple bins on it. Craig Moates I beleive has a device that can do that if you go to his website.

smartman__007

iTrader: (1)

Thanks Grim. I always run the 89 Octane (10% Ethanol) in all my vehicles because it's cheaper and better octane.

What Constants should be changed between the bins? In theory I should be able to change constants but leave the VE tables and such alone?

Grim Reaper

You don't need to change any constants. I would work on the main spark table so it is constant between the two bins. Then for P/E spark, you could add a little extra spark for the ethanol bin.

As well, you could invoke Highway Mode (if that particular calibration uses it) and try adding a little extra spark for the ethanol bin as well.

It's pretty much the same changes you would make if you wanted to make different 87, 89, 91 & 94 octane bins (which I have tried on my $8D many years ago). Because I was able to run so much more spark advance with the 94 (both for HM & PE), I found that increased gas mileage for 94 compensated for the lower octane bins PLUS I got the better performance with the PE.

These are things you need to try & experiment with to see what works best for you.

rhuarc31

Grim's got a lot of good points. You can however build a motor that will kick butt on E85, BUT it has to be purpose built to take advantage of it, not a compromise that will run on regular gas too. Bump the hell out of the compression, an octane level of 105+ will allow quite a bit. This will also help you get some of your lost mileage back. Ethanol does have quite a bit less energy per unit than gas, but stoich is something like 9.3 to 1. When you add the extra fuel to the mix you actually end up getting a little bit more power total, though your fuel system better be able to handle the extra load in addition to the corrosiveness, just check out how much larger the jets are on alcohol carburetors that will give you a clue. It does burn slower so run more timing.
Also cools the intake charge more, which we all know helps, especially in boosted applications.

More cons though, ethanol absorbs water way more easily than gas, so if your vehicle spends any time sitting take that into account.
Ethanol also doesn't vaporize as easily when cold, so if you live in a cold climate be prepared for harder starts in the cold weather.
Even with subsidies, watch the price of E85, a lot of the time its more expensive than regular gas, trust me I own a gas station, I deal with it everyday.
In addition to the rest of the fuel system, lots of injectors are not ethanol compatible, so be careful what you buy, and you will have to buy them, see the note about increased fuel capacity above. I forget the exact conversion factor but a motor will need a pretty good step up in injector volume to feed enough ethanol in.

I built a carbureted motor to run E85, and it's a fun healthy motor with a lot of snap. Of course it's got 13.5:1 compression (running pure ethanol you can go to 15 or higher, but I wasn't sure of the top limit of E85, I'm probably pushing it as is). I had to jump up jet size in the carburetor around 20 sizes, which mandated a holley, I couldn't get jets big enough for a quadrajet. Being carbureted and E85 it's a real BEOTCh to start when cold. I haven't run the motor long enough to tell, but I have heard that the ethanol will be much harder on washing oil off of cylinder walls as well, accelerating wear, but I have no evidence, just heard it enough that I'm keeping an eye on it. Love the power of the motor, runs like a raped ape. I am glad though that I put it in my trail truck though and not a daily driver.

junkcltr

iTrader: (1)

True, ethanol has a higher octane rating. In the end, the octane rating at the pump is what is stated. 93 is still 93 when it has 10% ethanol in it. I wish it was 93 octane + 10% ethanol. The gas companies cheap out and use a lower grade base gas. More timing is not the way to go unless the engine needed it as is.
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It is 89 octane.


EDIT: The best fix for octane I have found is spraying it with an approved pump flowing denatured alcohol (ethanol) through a misting nozzle.

Grim Reaper

Rhuarc, great input. I also find it interesting that you are using a carbed vehicle as it has always been my belief that carbed vehicles best benefit from ethanol because: 1) they are simpler and hence less costly to convert and 2) ethanol burns far cleaner than gasoline and hence carbs get the greatest benefit of all from this point (unless the carb is, and remains, perfectly tuned).

When I used to live in another area which was subject to IM240 dyno emission testing, we would add ethanol to the fuel if we had a vehicle that "just failed". The clean burning ethanol would get the vehicle "on side".

I also agree emphatically with your point that it is best to build the vehicle to specifically use E85 (instead of dual purpose). "Compromise" solutions usually are great at nothing.

MarcusMandarino

Friends,

I have just made the upgrade in my carb ' 85 berlinetta to TBI based on ECM 8746 with ANTT.
I would like to share information and knowledge with the friends of Thirdgen.

Here in Brazil we have two types of fuel, E100 and E25.
Nowadays, all the cars made in Brazil allow any combination of these fuels. They are called flexible. The cost of our ethanol is approximately half of the price of the gasoline, both without subsidies. We produced the whole ethanol and gasoline that we used, but our prices are significantly higher than in the USA, ~ $4.75 for E25, ~ $2.65 for E100....

My car is with 50K miles on it and I have been using all these years E25 without problems.
Now, with TBI I hope to improve the performance and the economy.
I understand that need to alter the tables VE and SA besides the constants AFR.
GM uses in the cars produced here AFR = 13.3 for half load and 12.2 for total load (for E25).
I intend to correct the tables of fuel in more 8%, that is the efficiency difference between E25 and the pure gasoline. I think It's easy to verify the result looking at BLM.
And for the tables of SA? I know that I can advance spark, but how much? E25 has 93 octane.
Will be an experimental method? To increase 3 or 4 degrees and glance for the knock counter?
Does something exist more than I should worry?

Thank you,
Marcus

RednGold86Z

iTrader: (1)

Just to add to the conversation a little, although not ethanol:
We're currently working on a methanol (M100) project (1.5L 4cyl) that's dual fuel (two tanks/pumps/fuel rail/injectors/regulator). The project is still in infancy, but:
When switching to methanol, there is a significant increase in torque at part throttle, and even idle, even with the same spark advance (same throttle position on chassis dyno, switching back and forth from gas to methanol = torque difference). I don't have numbers yet, but will in a few weeks.
Idle required about 10 steps less with methanol, unless gas idle had about 10 degrees more advance. Keep in mind idle spark advance is not MBT, rather it's EGT targetting for catalyst heating / keeping active.
Theoretically, methanol should release about 6 to 7 percent more power when burned stoichiometrically. Ethanol theoretically would be about 3%.
Transient fueling needs more magnitude with methanol, even when % based.
Rich burning is easy and tolerable (not as sensitive to excess richness) (except it produces formaldehyde with methanol...).
Parts show wear and a white residue (system parts were not spec'd by me, so I'm not sure whether they are fully compatible, yet). A pressure regulator failed yesterday actually (stuck at high pressure).
Obtaining this rare fuel is a pain, and not sure why the customer wants it.

As far as ethanol - why increase demand on the food chain and land resources? The effects are spreading rapidly already.
They need to be working on that thing on the delorean that eats garbage. And build a few nuke plants in sunny windy areas surrounded by solar fields and windmills, and place efficient battery reserve packs in millions of households to reduce peak energy demands from power plants and to store the excess solar and wind energy. And tax electrical usage un-proportional to usage.

Grim Reaper

I would love to get into further debates about ethanol (corn vs sugar cane source) or ethanol vs methanol; as well as the economic viability, the ramifications, etc. However, that is going beyond the scope of DIY Prom. It also tends to raise tempers up and hijacks an otherwise interesting subject.

So let's keep this post limited to only tuning tricks & suggestions, as well as mechanical modifications required to run ethanol, methanol or other even other fuel sources like propane.

I think this could be a great addition to our tuning guide when it has finished.

RFmaster

Here is the question - is there a sensor that can detect % of ethanol in the fuel stream??? With Bin switching alternative tables can be loaded into ECM depending on available fuel...

//RF

rhuarc31

With E85 an o2 sensor will work, not sure about pure ethanol. There is a way as racers running alcohol have data logging capabilities for it, but I'm not sure if its EGT or O2, or what.

MarcusMandarino

Because E25 is 8% less efficient than pure gasoline I understand that I should correct the tables of fuel. I think simpler to correct BPW once this influences the whole supply of fuel. Am I correct?
Thanks for help...

junkcltr

iTrader: (1)

An O2 sensor detects oxygen. It is all about lambda. If the ECM you are using has unused on/off inputs or A/D inputs then you can add a toggle switch and some code that changes the stoich AFR using the switch.

The fuel system needs the upgrade for the amount of ethanol used.

Grim Reaper

E25 is not available in North America almost all of the car manufacturers state in their manuals they do not recommend anything more than 10%, so the oil companies only make 10% the highest concentration (except for E85 which you car must be designed for).

But, excluding the mechanical issues and strictly the tuning issues; the VE tables are not a major concern unless you want to run a different AF ratio for part-throttle stoich & WOT P/E. (Which is probably not a bad idea).

I have never spent any dyno time tuning for ethanol (other than the 10% that may have been in the gas tank). But I would be curious what the optimum AF ratio for other ethanol concentrations would be and with a little experimentation, it would be easy to figure out.

While my hunch is you probably need to richen it up a bit, I suspect it isn't too much richer than gasoline's optimum AF ratio (12.6-12.8:1) as it has more to do with the amount of air you need to obtain max explosive power, rather than the efficiency of the fuel itself (due to different chemical composition).

But some dyno time will solve that.

rhuarc31

With that small an amount of ethanol your O2 sensor should be able to compensate during closed loop operation without much tuning changes. WOT I'd guess that grim is right, a bit richer but not much. If you're going to be running it all the time, I'd even say that the small changes needed would be well within the realm of just some small fuel pressure adjustments, provided you have and adjustable regulator of course.

HaulnA$$

A couple ot things seem to be unclear here. First, as 'junkcltr' mentioned, an O2 sensor does not measure AFR but rather Lambda or the stoichiometric point of fuel, any fuel. It doesn't matter whether you're running gasoline or E100, a narrow band O2 sensor will toggle around the stoich point of the fuel in use. To use any type of fuel other than what the calibration is set for requires only a change in stoich constants and scaling AFR based tables from a Lambda standpoint. For example, if you were to switch to E100 which has a stoich rate of 9:1 AFR, from gasoline which has a stoich rate of 14.7:1 AFR, you would need to set the stoich AFR in the cal to 9:1 and scale all the AFR based tables by a rate of .612 (9/14.7). You can check yourself this way. It is widely accepted that a Lambda of .85 is needed for PE or WOT. .85 * 14.7=12.5., 85 * 9=7.65 and .612 *12.5=7.65. Mechanically speaking, as "junkcltr" also mentioned, the fuel system needs upgrading to run pure or near pure alchohol. Non-corrosive seals and line need to be used as well as a pump rated for alchohol. Most importantly, the injectors need to be sized accordingly. For example, if you are using 30# injectors for gasoline, you would need to install 50# injectors to run E100 (14.7/9).

I drive a TBI truck as a daily driver and only E10 or E85 are readily available in the DFW area. 100% gasoline is almost non-existant. I had a perfect tune set up for gasoline and when all the blends around here went E10, I set the stoich rate to 14.13 and scaled the AFR's and all the BLM's fell back in line with where they were before. No other fuel tuning was needed.

This leads me to my second point. VE is independant of the type of fuel in use. It is a measure of the engines mechanical ability to move its calculated maximum volume of charge versus RPM. The VE tables do not need to be changed to convert to alchohol.

My wifes daily driver is an '03 flex fuel Tahoe that I have been tuning on for a couple of years. It has a sensor in the gas tank that measures the amount of alchohol in the fuel by determining the amount of O2 present in the fuel and standard O2 sensors, the same as in a non flex fuel vehicle. In the calibration, there is only one main VE table and a 2D table that sets the stoich rate of the fuel vs. % alchohol in the fuel as determined by the tank sensor. All the other fuel related tables such as open loop fuel ratio and PE fuel ratio are based on an inverse Lambda term so the proper AFR is always achieved no matter what the stoich rate of the fuel. There is also a spark advance table vs. AFR vs RPM to help with the octane level increase. E85 is 105 octane.

Tuning for E25, or E85, or E100 is not as complicated as it may seem when it is all said and done. The mechanical portion is much more involved. HTH

titchener

"My wifes daily driver is an '03 flex fuel Tahoe that I have been tuning on for a couple of years. It has a sensor in the gas tank that measures the amount of alchohol in the fuel by determining the amount of O2 present in the fuel"

HaulnA, thanks for that explanation of tuning for alcohol mixed fuels, that was good stuff.

The sensor you mentioned above sounds pretty interesting, is that an aftermarket device or a factory one you adapted?

Are you using an ECM that lets you read that sensor on the fly and make the adjustments you described, and if so which one?

Thanks,

Paul T.

Ronny

iTrader: (1)

Question on LAMBDA?

It is apparent that our .bin needs some changes when running E10 and i have done so.

My question is my WB02 sensor as far as running E10. If WB only reads unburned 02 in ext stream and all the 02 is consumed, Lambda then reads as 1.00 regardless of fuel. Would that suggest the WB02 does not need to be calibrated for E10 or E85 for that matter for Lambda only? I believe the controler which reads lambda and A/F would need to have A/F calibrated as it defaults to 14.7/1 as stoich?

when my WB datalogs are referenced to A/F(14.13 for E10) in graphing only then do I need to correct my datalogs for the A/F that i am shooting for(14.13)? If I show lambda in logs I need not correct for fuel? Does this sound correct?

RBob

iTrader: (1)

Lambda at stoich is 1.0 for any mix of gasoline and Ethanol. If the WB can display/output the lambda value that is the best way to use it.

Using 14.7:1 as 1.0 lambda has it's roots in gasoline. It is the AFR for gasoline. Interestingly enough many use the fuel-to-air (FAR) instead of the usual AFR. But it is still the AFR for gasoline, not something with alcohol in it.

If I show lambda in logs I need not correct for fuel? Does this sound correct?

Yes, you are correct.

RBob.

HaulnA$$

The sensor and PCM are the GM pieces the truck came with from the factory. As far as monitoring the sensor, the GM OBDII Fuel Tank PID's have a "Desired AFR" PID that is derived from the sensors input. The PCM is the 12200411. HTH

Grim Reaper

Based on some of the comments above and what I know about the oil industry and gasoline (virtually all gasoline where I live has some ethanol in it, whether you like it or not): when tuning, do not just accept a particular AF ratio (say 12.6 for WOT) as your "optimum".

If you are trying to maximize your power, you really need to test it on a dyno with a WB to see at what point you obtain max power. The particular brand of gasoline and the amount of ethanol in it can have an effect where you will obtainn maximum power. And, if you use different brands of gasoline, you optimum AF ratio may be a little different.

Only quantitative testing on a dyno preferrably backed up with track time will obtain the maximum point, if that is your true objective.

Conversely, if you are willing to live with 95-97% potential, you don't need to do as much testing and probably live with "given standard AF ratio".

Grim Reaper

Not to be a bad guy, but I (and later others) mentioned this point way back on the post #7. I guess that is what happens when people don't read all the posts before replying. At least have the courtesy to give proper credit.

HaulnA$$

I did read all the posts, more than once. My bad! I understand that a sin of omission is still a sin but not giving you credit for mentioning the corrosiveness of alchohol first was not intentional nor was I trying to flame you or any other member who replied to this topic. I thought I was dispensing helpful tidbits of information derived from experience gained through knowledge learned here and elsewhere and I always try to give proper credit. I know what it is like when someone takes credit for your own ideas. I will be the first to admit that I don't know everything so I keep my replies limited to where my knowledge lies. As I am sure most everyone here knows, you are a very knowledgeable member, otherwise you would not have been selected to be a moderator. At least give me some respect for bieng a knowledgeable member as well.
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Grim, are you referring to my post stating that "It is widely accepted that a Lambda of .85 is needed for PE or WOT."? If so, I was'nt implying that this figure was etched in stone. I was merely trying to convey a "tuning trick & suggestion" method for tuning based on Lambda versus AFR. I like think the frequenters of this forum are well versed in how to tune for max power and know that every combination is unique and therefore, so is the tune. In order to keep my post out of the novel category, I did'nt see the need to elaborate on every detail. Just trying to contribute to the topic as is the purpose of these forums.

Grim Reaper

No, I was not referring to you (or anyone else) when I was talking about the AF ratios. I was just giving "general advice" for any tuning for WOT - and mentioning that even "supposed" pure gasoline may also contain some ethanol whether people know it or not.

And if a person was tuning with "pure" gasoline (as an example), the 12.6:1 is the AF ratio that is most often claimed by "experts" as the optimum AF ratio (and I will not dispute that). But, in my real life testing experiences on a dyno, I have found that 12.6 only to be a good starting point. The final "optimum ratio" that yielded the greatest HP quite often will vary from 12.6 (though usually not too much). And variance from 12.6 is due to a number of factors, including the accuracy of the WB itself. Hence, my recommendation that a person is wise to actually do some dyno testing to find his engine's optimum AF ratio and not just accept 12.6 as gospel.

Even "pure" gasoline's part-throttle stoich of 14.7:1 is a number that is "compromise". The "standard 14.7:1" is just the AF ratio that provides the best compromise of ALL measured pollutants while also providing reasonable fuel economy and driveability. But, it's not an "optimum" AF ratio for part-throttle - just a compromise.

A higher AF ratio gives better fuel economy, but increases NOx levels and can have some driveability issues as well (requiring further tuning). A lower AF ratio tends to improve driveability but decreases fuel economy and increases HC.

With ethanol, a person will need to address the issue of the AF ratio - and that is also going to depend on the concentration of the ethanol and whether his engine was built to run ethanol as it's primary fuel. As mentioned previously by others above, to truly get the maximum potential out of ethanol (in the higher concentrations), it would be best to build the engine with specifically for ethanol and use the higher compression that an ethanol engine can tolerate.

Then you can get maximum power and even better fuel economy.

smartman__007

iTrader: (1)

Sorry I haven't been checking this. Been pretty busy with college and everything else. I finally took the plunge though and got it running with ethanol. You would not believe the change in tune of the car. Stupid thing is though we found our Fuel Pressure problem. A broken line inside the tank.

It is more or less a test for me right now. If it's possible with a vehicle not meant for ethanol just imagine the gains with a vehicle designed for it. I am not on my home computer that has all of the bins but I just changed the constants down to 9.0 to 1 and it seems to be running from the last good tune I had on the car. Obviously the pumpshot and other various VE tuning parameters have been pretty well overkill but that will come when I get more time. I'll keep everyone posted but it seems it's possible. Hopefully the lines and everything will stay up to the ethanol. There are two pieces of rubber line that weren't repleaced but the others are either hard lines or replaced with alcohol compatible lines. No leaks, great pressure, (25 psi @ idle, 35 @ WOT). Thanks for all the help everyone and I'll post comparison bins to show what I changed as soon as I get them from home.

s24a

I will add that the GM ETOH (Ethanol) sensor has two part numbers:
First is 12568456, and the second is 12570260.
These sensor have a FREQUENCY output, and varies linearly fro 50Hz to 150Hz, where 0% ETOH is 50Hz output.

Also, the width of the pulse out varies from about 1 to 5 msec depending on temperature (1msec is -40ēC and 5msec is ~100ēC), so you can calculate the fuel mixture's Ethanol boiling point for potential vaporlocking as well, if you wish. You would need a distillation curve table for this.
You need to tie the sensors output through a 10K Ohm pullup resistor to +5V.
The connector shell for these sensors is PN 12126121, the pins (3 required) are PN 12048074.
Or you can buy a pigtail harness PN 88987992 (AC Delco PN PT-1795)

This sensor is also compatible with METHANOL, and also Diesel, so can be used for other fuels besides Ethanol blends.

BTW...Both Ethanol and Methanol are "dipolar" fuels. Meaning they carry an electrical static charge. So make sure that your wiring is always set up consistently on the injectors with the (+) of the injector pins on one side of the injector (generally marked), and the (-) on the other side as a precaution. It is also good to make sure that the fuel filter in the system has either a metallic shell, or if plastic, has metallic threads in the plastic to dissapate the charge. I have seen charge buildup and arcing on plastic parts, and that is NOT good. It can perforate the system and cause fires!

Ethanol and Methanol can permiate nylons, so that is an issue, as well as swell the nylon fuel filters shut in the in-tank pickups and the injector inlets, so thay need to be compatible as well.