jetting for E85 (ethanol)

[Rema1000]

I'm converting to E85 (ethanol), and wondering how far to enrichen the mixture.  I put-back the stock airfilter, but found that with E85 fuel, I couldn't idle smoothly without the choke on 1/2-way (ethanol is 30% oxygen, so doesn't need so much air).  With E85, I found that the bike bucked pretty wildly, especially from 3k-6k RPM.  At 7k, I could still feel some popping, but it wasn't as noticeable.

Just to see how far off I was, I tried restricting the airbox: I put a bathtub drain strainer (hair catcher; a plastic basket with holes) over the opening of the air filter... but I still couldn't get a good idle without the choke.  Then I stuck a Dixie cup in the strainer, almost blocking it off.  Finally, I was able to get the bike to idle at 1500RPM with the choke off.  But it still seemed pretty lean at idle: if I blipped the throttle, the RPMs hung up high for a few seconds before falling.  Riding around with the air blocked-off, it's fine starting in 1st, but when I shift up to 2nd, it bogs-down completely (not too surprising).  So I just rode a bit in 1st at 5k RPM.

So I think the mixture is pretty far off.  The most-significant rejetting I see mentioned on GSTwins is to use 40 pilots and 150 mains, and shim with 2 washers (for a V&H Performance exhaust and K&N pods).  Can anyone with the performance system guess as to whether my description sounds leaner than theirs would be, with performance intake/exhaust, but with the stock jetting?  That would give me an idea where to start playing.

I'm wondering if I should maybe start with 42.5 pilots, 150 mains and 2 washers, and see how that works.

[The Buddha]

Nope... someone told me he was running 180 mains and was still lean... That was back in 1997... when I had no clue about filter and pipe setup etc.
It ran like a bat from hell with ethanol and evidently it runs very cool and doesn't strees the motor as much. Is it true... Ethanol wont knock .... ever
Cool.
Srinath.

[Reknelb]

We do alot of work with micro sprint cars at the shop. When they convert to METHONAL, the rule of thumb is a 70% increase in fuel is required. So take what a stock carb has and go bigger by 70% on all the circuits (pilot, needle, needle et, main) BTW you also have to change the float needle valve, and needle valve seat to allow for more fuel.  Usually you have to be running high compression, and advance the timing too when running methonal. I'm not sure if ethonal is the same or similar as methonal but, you cant leave it in your carbs or it will eat away the seals and other rubber components.

In my opinion, the 33mm carbs that are on a stock gs Just doesnt flow enough to run that type of fuel.

[Rema1000]

Methanol is 50% oxygen, and ethanol is 35% (and gasoline is 0%).  I've seen car conversion instructions saying to increase all jets between 20% and 40% from gasoline.  There's not really much penalty for running rich, so I'd figure a 40% increase in fuel for max. performance (and 70% for methanol).

But I was thinking of starting with just a 30% increase, which should still be in the ballpark, and the little 33mm carbs just might have a chance .   So I may start with 157.5 mains and 50 pilots.   I've heard of 33mm carbs being used with mains as large as 192 (but I don't know how well it worked).

But I wouldn't know what to do about the jet needle.  As you keep shimming it, you also shorten its useful range (you get to main jet faster).  So trying 3 or even 4 washers may be just silly.  Maybe I'd need a narrower jet needle (sand it down?), or a wider needle jet.

[Blueknyt]

start with 160 and a 45 then ride it, if it feels close, spend the cash for a Dyno run,  a shop near me will do a single pass dyno run for 25$  I still need stock Needles and emultion tubes for mine.

[Rema1000]

start with 160 and a 45

45 pilots were way too small. I drilled the pilots out with a #76 bit (0.508mm), then a #74 bit (0.5714mm), which finally worked well with the 160 mians and E85 fuel. The idle mix screws were only 1.5 turns out, so 55 pilots would probably be the right stock size for E85.

When setting the idle mix, you could go way too rich, and the engine wouldn't bog-down.  I enriched until RPMs quit going up, then stopped right there. The result was pretty nice: the bike started easily, and warmed-up even faster than it did with stock jetting.  It idled smoothly at 1k RPM too!

The bike is very wimpy off the line: I have to goose the throttle and ease the clutch when starting out; probably related to having not modified the needle at all.

I got 29mpg on the second tankful of E85, which was less than I had hoped.  I hit reserve at 80 miles!  Not cool.

I put-in hotter plugs to burn the alcohol better, and leaned-out the idle mix screws to be 1/4 turn leaner than the highest RPM point. Then I got 35mpg from my last two tankfuls, which is OK for E85.  But the bike is harder to start, and kills after the first couple of starts. About the third time, it keeps running.

I'm going back to the richer idle mix, and will see how bad the mileage gets.
Maybe the better MPG was from learing the new feel of the clutch, or the hotter plugs giving a better burn.  Also, the timing needs some serious advancement (like 10-15 degrees).  Alcohol has a really slow burn, and  advanced timing should let the fuel burn completely.

So, current system is:
E85 fuel, 105 octane (contains about 35% oxygen)
stock exhaust, K&N drop-in filter with restrictor
57.14 pilots, 160 mains, stock needles
idle-mix screws on the lean side
35mpg

[JamesG]

Maybe if you went slightly richer on the pilots (drill them out a bit more) and either leaner on the mains or take the shims out of the needle. It would start better and not run so rich up top...

Are you using commercial pump ethenol gas or pure ethenol from some other source (making it yourself?)?

[jake42]

not to completely threadjack, but's the advantage of running ethanol over gasoline aside from cooler running engines?

jake

[The Buddha]

ok 60 pilots 155 mains and maybe lift the needle 2-3mm and I can switch to ethanol... sounds good... Let me know what your final setup is and where it runs good... I want to do it. Ethanol is an industrial by product, and presumably will get cheaper in future. Anyhow its a nice mod... and those puffy white clouds of pure oxygen you leave behind.... Lovely ok ok not pure Oxygen, but more like steam and less of the nitrogenated crap and fewer hydrocarbons.
Cool.
Srinath.

[johncam4]

my 2000 ranger is supposed to run on e85...it has the leaf sticker on the tail gate.  I think its great but they dont sell it in texas...were do yall get it.

[Blueknyt]

isnt that the fuel they make from chicken and pig manuer?

[Rema1000]

Maybe if you went slightly richer on the pilots

Thanks, good thought.  If the richer mixture screws kill the gas mileage again, I'll look there for a few MPG.

Are you using commercial pump ethenol gas or pure ethenol from some other source (making it yourself?)?

Making it myself would be... stinky .  And big, like using one 55-gallon drum (fermenter) per 100 riding miles per week.  In Minnesota, there are about 45 gas stations that sell E85.  The price at the pump varies quite a bit, since it seems to have more to do with local supply/demand, than actual cost (I've seen from $1.25/gal. to $1.78/gal.).  But it's worth it to just buy it at the pump, instead of making it.

Some thoughts about E85 for anybody thinking of it:

-you have to rejet for E85, and can't buy E85 in every state, so long multistate rides would be complicated in "corn country", or impossible in some states (Srinath?).  And your miles per tank will be less (22% less for me so-far).
-started-up on the first try for me on a 42 degrees F spring morning.  But don't expect it to start from cold temps as well as gasoline.
-you can burn it with just a rejet, but there won't be any extra power.  To maximize power, I think you'd want hotter plugs, advanced timing, higher compression and multi-spark ignition.
-When it's really rich (like right after starting-up), it smells like someone just ripped open an antiseptic Prep Pad; an astringent smell like a hospital.  When you fill-up, there are no visible vapors, etc.
-your carbs will stay squeaky clean, as if you soaked them in alcohol

I think that today, you won't save any money with E85 (although your money will at-least stay local): I get 78% the gas mileage of gasoline, but the fuel costs 87% as much as gasoline.   But if people buy into it, it would be made from wood chips and corn stalks, and would be much cheaper (like Srinath said, industrial byproducts).  So I thought I'd just give it a spin and see if it is really a workable fuel.
\

[MarkusN]

-your carbs will stay squeaky clean, as if you soaked them in alcohol

Which you did, because Ethanol is alcohol.

One advantage not mentioned yet, but the main one in my book (not very popoular in the motoring community, but I'll blather anyway):

Ethanol is 100% sustainable energy. It's made from products grown now, using carbondioxide from the atmosphere and solar energy.

So no wasting of a resource that our grandchildren might use for better purposes than to load the atmosphere with CO2.

[JamesG]

Yup Its a pretty much given that ethanol and hydrogen are way we are going to have to go when all the dino juice is used up.

Looks like we are now in the beginings of that now.  Its about time!

[MarkusN]

Problem with hydrogen is that it's only a container for energy, though, not a source. You gotta produce that molecular hydrogen somehow. In practice that'll probably mean a few hundred nuclear plants. Wonder where you'll find the population willing to put up with those and the waste they produce...

Ethanol on the other hand is produced from substances that have already stored solar energy when they grew.

To be fair, there are different ways to produce hydrogen.

[Jasco]

isnt that the fuel they make from chicken and pig manuer?

Methane is made from animal waste.  Ethanol can be made from plant material.  The shuttle busses at our state fair run on ethanol made from corn plants.

Matt

[Rema1000]

Many current fuel cells were built to extract energy from alcohol (at least, it appears so from reading EETimes).  Hydrogen would work, too, but it is much harder to deliver to filling stations, and harder to transport in the vehicle.  A liquid like LP or ethanol (or gasoline) simplifies delivery and storage.  So I think that ethanol could be a good step towards fuel cells: build the delivery network today, then go straight to fuel cells someday.

[mareaturbo]

Good morning.

I want to buy a GS 500 and convert it to ethanol too. Here on Brazil we proudly use this fuel pure or added to gas (E26) since 1978, reducing pollution and oil dependence. Here, its prize (~35-50% of gasoline according the season) takes its use an finnancial advantage. My master thesis is about ethanol-powered vehicles too.

But infortunately there are almost no motorcycles running on it.

Forgive my ignorance (nobody borns knowing anything, my mother says), but, what does mean "mains" and "pilots"? I didn't get an engine-related meaning for them in any Portuguese-English dictionary. Your experience in resetting up carburettors will be very useful to me.

I am planning too to cut 1,5mm of cylinder head, to increase compression ratio from 9:1 to something a bit lower than 12:1. Is there any problem? Will I reach some cyl-head cavity? Is it needed to cut pistons to avoid contact with valves?


How about the ignition map? Can you give more details and suggestions about modifications on it?

Thanks for attention. mareaturbo@zipmail.com.br

[Roadstergal]

not to completely threadjack, but's the advantage of running ethanol over gasoline aside from cooler running engines?

It's a more quickly renewable resource than gasoline.  Orders of magnitude more quickly.  The by- and end-products of combustion are less nasty, too.

[vtlion]

plus... your exhause will smell like booze  :lol:

I ran my old Ranger on E85 when I could.  It ran well, but the mileage hit made any financial/emissions gains a wash (30% cleaner emissions, but only about 70% of the mileage  :dunno: ).  It also sucked that there was only ONE station in the entire county that sold it.... the county fuel depot  :x