flex fuel 8

[Lou Scannon]

There are sensors in the fuel line that tell the ECU the percentage of alcohol in the fuel so it can make fueling adjustments. I don't know what principal they are using to sense it.

Sounds plausible but I haven't come across one. Can you cite a late model application using such a sensor? I'd like to investigate.

I would gladly pay the $3.00 for a gallon of E85 if I had a flex vehicle.
plus less pollution right?

IF the calibration for E85 is as well optimized as the calibration for petrol, then yes, HC, CO and NOx should all be lower. And then, if CO2 is classified as pollution (which is debated), then cradle to grave CO2 "pollution" might be reduced also, but that is a hotly debated question, due to the existing methods of ethanol fuel production.



"Schiefgehen will, was schiefgehen kann" - das Murphygesetz

 

[dgallup]

Pat - Corn based ethanol production comes from the fermentation of the sugars, not the cellulose, just like Brazil's sugarcane based ethanol. The vast majority of the plant matter (cellulose) is unused. If fact it's sold as live stock feed indicating just how much of the energy content is unused in ethanol production. There are lots of companies (& federal $$$$) trying to tap all the rest of the energy with what they call "cellulostic" fermentation, don't ask me to explain, I'm no chemist. The goal is to use all the cellulose in cheaper sources like switch grass.

Mfgenggear - It's not really difficult to make a system E85 compatible, it's not very aggressive. The people who have had the most problems with ethanol are the boaters because of things like fiberglass tanks dissolving and cheap fuel lines, pumps, etc. Everything sold automotive in the last decade+ has been ethanol compatible at pretty much any concentration.

Methanol is a totally different story and you will be hard pressed to find compatible elastomers, fuel lines, pumps, etc. Only the hard core racing community uses it and not so much there anymore since even they have gone "green" and switched to ethanol in many series.

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[patprimmer]

E 85 is ethanol not methanol. They have similarities but they are quite different in some ways. Ethanol is the product of fermentation of starchy or sugary vegetable.

E85 is ethanol based and while moderately corrosive, it is nowhere near as corrosive as methanol and SS lines are not really required.

You do need to ensure all hoses are ethanol compatible. Anything rated for methanol will be more than good enough. Anything rated for strong spirits like Vodka will also be good enough.

I would tend toward brass fittings and copper or SS or coated steel or even nylon pipe/hose.

For ethanol, you need to allow for about a55 to 60% increase in fuel flow everywhere in the system including the tank breather vent.

The carby will need bigger "alcohol" SS needle and seat. It's generally easier to use dual inlet carbies if they are Holley type.

You need to increase main jet CSA by about 55% but also idle and intermediate fuel circuits. You need to ensure the emulsion tube wells will also handle the extra fuel flow. Sometimes it's easier to just use a greater number of carbies with smaller chokes for the same airflow but more potential fuel flow. You still have to tune the jets though.

An extra booster electric fuel pump and extra fuel pressure can help get the flow up through std size pipe and fittings, but once in the float chamber of course this does not help.

Some manufactures off methanol carbies. They would flow to much fuel, but could be easily jetted back and maybe the idle could be fixed with the adjustment screws. The intermediate circuits might still be rich though.

If you go methanol, the same deal only more so. You would need all fuel flow areas to be slightly over double.

Another issue is cold weather starting. Ethanol and especially methanol don't like to start in a cold engine. High compression helps here as does a strong ignition system, but most methanol fuel race cars use a spray bottle with normal petrol to start it up. You could possibly rig up a seperate petrol squirter powered by a small electric fuel pump and push button activated as a starting primer. Just don't touch the throttle until it fires.

Of course the limited range and availability of fuel when away from home should be obvious.



Regards
Pat
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[mfgenggear]

dgallup

I am confused, I meant ethanol still. & ethanol fuel , senior moment kicking in.
LOL
I hate when that happens.
Items I would have to replace ?
Tank
fuel lines

so existing Holly or edelbrock intake & carbs.

mfgenggear

 

[mfgenggear]

OK thanks pat.

ignore my last post

Mfgenggear

 

[mfgenggear]

I did read, for previous versions of flex cars, a separate start up tank with gas was used.
how could I jerry rig this?

Mfgenggear

 

[patprimmer]

Intake will be fine.

Carby will need mods.

A methanol carby will have the corrosion resistance well and truly covered, but it's easier to increase the fuel flow drilled restrictions/jets and slots than to decrease them. Of course the screw in ones can be easily replaced with suitable size.

I think you can buy methanol conversion kit for Holleys with all materials upgraded where required. Things often overlooked are needle and seat and accelerator pump diaphragms.

You also picked up on the tank. That is an often overlooked item. Even serious racers use aluminium tanks which after only a few years start to corrode and produce a white fine powder that racers call white rust. Once again, ethanol is not as bad as methanol. There is no problem until the anodised layer is eaten away which takes some time, especially if hard anodised, but once that's gone, the corrosion really accelerates.

Regards
Pat
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[Lou Scannon]

BTW, the "white rust" from aluminum is in the form of a gel when it is immersed in the fuel. This gel plays hell with fuel filters. The recommended coating for aluminum parts wetted with methanol is electroless nickel plate. I expect this would be fine with ethanol as well.

"Schiefgehen will, was schiefgehen kann" - das Murphygesetz

 

[dgallup]

Electroless nickel does very well in ethanol.

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[swall]

hemi--the presence of "white rust" indicates corrosion, most likely of an aqueous nature. In that case, you do not want an electroless nickel (ElNi) coating on the aluminum. If a pinhole developes in the ElNi, you will be in a galvanic corrosion situation with a large cathode surface area (the coating) and a small anode area (the aluminum exposed by the coating breach).
This will lead to pitting and eventually perforation of the aluminum.

 

[Lou Scannon]

Agreed, the plating is a band-aid for parts that are originally aluminum. It will be down to the plating quality whether there are pinhole issues or not. Preferred material is of course stainless steel in suitable grades.
At any rate, during the M85 era in California, there were terrible issues with the drop tubes going down to the supply tanks at the fuel stations, since they were bare aluminum. The gel resulting from the corrosion was pumped into vehicle tanks, and clogged their fuel filters. A corrective action that was employed at the time was to replace the drop tubes with nickel plated ones. Since the integrity of the tubes was not the issue, only the contamination of the fuel, I expect that this corrective action would prove to be effective. The M85 era came to a fairly sudden end, before the life expectancy of the plating (in methanol exposure) was really tested.

"Schiefgehen will, was schiefgehen kann" - das Murphygesetz

 

[bradrs]

hemi,

You are correct about the function of using the fuel level sensor to watch for a refill event, and then after that there is a learning period where the ECM attempts to "learn" the new ratio of E85:gasoline based on lambda sensor/fuel trim feedback, allowing it to adjust the fueling to mix. This was done for several years on recent GMs, and I think Fords too.

However, the earlier flex fuel vehicles here in the US, and I believe many in other countries, use an ethanol sensor. Also, the manufacturers here in the US are switching back to using a sensor. The other strategy was to save them a few bucks, but it was problematic, complicated to program, slow to respond, etc. A failed fuel sender would then cause issues with the car relearning the fuel ratio... Too many issues.

Of course when I go to look for the info, someone has walked off with it. So I can't give you an exact part number or application for the newer vehicles.

But here is a place that makes a lower cost copy of the factory sensors:

http://www.pointaengineering.com/

And if you search for "flex fuel sensor" or "fuel composition sensor" with respect to GM or Ford you will find plenty of them around. I think Megasquirt even has details on how to interface to them.

 

[bradrs]

Ignore the link. They are a sensor "replicator", that are merely putting out the right signal, as if its on gasoline the whole time. If I remember right, that is something around a 50hZ square wave. Kinda pricey for a 555 timer circuit.

But there are plenty of places to get the sensor. Since the link above was worthless, here is the MS link that shows how the sensor functions, where to get it, etc:

http://www.megamanual.com/flexfuel.htm

 

[berkshire]

Mfgenggear
[highlight #EF2929]swall (Materials
hemi--the presence of "white rust" indicates corrosion, most likely of an aqueous nature.[/highlight]
That imfamous white rust has driven me nuts with outboard motors on boats for the last couple of years.
so I am now switching to a different flex fuel, Propane. It does not get the MPG that gasoline does.
On the other hand I am paying $2.19 per gallon for Propane in San Diego. You cannot get more Southern california than this
It also does not attract the water into the fuel that helps form the white rust.
B.E.

The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor

 

[bradrs]

On the conversion systems we make(automotive based) generally propane seems to have the game MPG as gasoline. CNG is down a little from either. How much % are you losing in the propane switch, and how are you metering it?

How big of a tank do you have for your propane powered boat? Seems like you could wind up adding a lot of weight with that.

 

[mfgenggear]

On the other hand I am paying $2.19 per gallon for Propane in San Diego.

berkshire

what the ? I also live in San Diego, I don't get propane that cheap. LOl

Mfgenggear

 

[berkshire]

mfgenggear,
You are right, I get the 2.19 price in El Cajon.
to get the lower price you have to go to the welding gas supply houses I.E. Westair.
Stay away from gasoline stations and especially Blue Rhino. they will get you for over $5 per gallon.

bradrs
I am currently using a dedicated Propane motor made by Lehr. It is a 5hp motor is burning less than 3/8 gallon per hour running solo at 75% throttle, and 5/8 gallon per hour running flat out pulling a string of boats. This appears to relate quite favorably to the consumption rates of the gasoline motors. I am chief of maintenance of a sailing club and purchased this motor for evaluation. I have five other motors in the 4 to 6 hp range. In the month of May of this year I spent $1600 on carb and fuel system parts, mostly due to water contamination in fuel
I am now talking with a conversion company about switching the other gasoline outboard motors to Propane.
In answer to your question on tank size, I am using one gallon tanks, which give an average of 3 1/2 hours run time. After I bought the one gallon tanks the maker of the motor told me that this engine will run equally well on a liquid propane supply, and suggested a 5 gallon tank laid on its side.
B.E.

The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor

 

[patprimmer]

In my experience an engine fully configured to optimise running on propane does a LOT better on propane than one configured for std pump petrol that has only had fuel system mods as necessary to run on propane. For one, propane can tolerate about two full points of compression higher.

Regards
Pat
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[mfgenggear]

berksire & pat

Thanks for the responses.
what are the requirements to convert to propane ,
I will also google this but I prefer to get first hand from the experts here.
how about a larger outboard motor. let say 70 HP, 4 stroke










Mfgenggear
if it can be built it can be calculated.
if it can be calculated it can be built.

 

[Lou Scannon]

berkshire, I may be preaching to the choir, but do be very careful with propane and water vessels. They can be an explosive combination, literally. Any leaked propane will pool at the bottom of the hull, forming a potentially flammable mixture with air. Assuming the dedicated propane motor you're using is intended for marine use, I'm sure all the proper precautions are prescribed by the manufacturer.

"Schiefgehen will, was schiefgehen kann" - das Murphygesetz