Converting a 1980 GSX250 to run on alternative energy.

[Alexires]

As talked about in Charles' "It's time for an Alternative Energy Source (http://www.roguesci.org/theforum/showthread.php?t=6184)" thread, I have an old Suzuki 1980 GSX250 that I am planning on converting to Ethanol to test the feasibility of running EtOH.

For completeness' sake, here are the relevant posts from that thread.

OK, for your alky-powered go-kart deal, start out by removing the carbs and setting them up to run on alcohol.

Requires steel-tipped needles and enlarging the fuel metering jets by 40% to start with (will prob. end up closer to 35%, but you don't want to damage it to begin with). Will also require mods to the idle, accelerator pump and mid-range circuits, but this will get you in the ballpark for now. If you can get a set of GSX 400 carbs, you might find the parts (metering jets, air bleeds, etc.) from them will suffice.

Get a heat-range colder set of plugs.

Replace rubber gas lines w/Teflon-lined steel-braided lines, sold at Summit, et al.

The carbs are aluminum, you will need to purge the fuel system after use, or come up w/a process (hard anodizing?) that will protect them. The fuel will need to be sealed from atmosphere when not in use for more than 5-7 days. The more water is absorbed by the fuel, the hotter the engine will run. Not a good thing w/air-cooled engines.

You will need to set up a test-stand that the engine can be run on for testing/tuning before you mount it onto anything. Hope you are good w/tools, fabrication, welding and etc. but this CAN be done.

This is obviously abbreviated. To relay to you everything that will be required would take too much space here.

Good luck.

Thanks for that Cobalt. I was wondering what I was going to do about the possibility of it running too rich (not enough air as it would be optimised for petrol) and that is a fantastic solution.

Tomorrow the carbs get removed and the preliminary assessment begins (current size of the jets, ringing around to see if I can get GSX400 carbs and multiple sets of the jets, etc.)

Excellent website here (http://running_on_alcohol.tripod.com/id32.html) that seems to have it all sussed. I might work off that for the moment unless someone thinks the info is crap.

Could you just explain your reasoning that an increased water content will increase mean engine temperature? See, I would figure that the energy content of the EtOH is constant, thus by having excess water, less EtOH gets to the cylinder, hence a lower cylinder temp, thus a lower engine temp.

Even if it is running hot (it is air cooled) that isn't such a bad thing, because the second step in my devious plan is to make use of that excess heat. But for the moment, let us concentrate on just getting the bastard of a machine to run on EtOH.

If you were to run alky in a gas carb, the problem would be terminal leanness i.e. too much air to fuel. Remember w/alky, MORE fuel and in your case, same amount of airflow.

Your carbs are equipped w/needles that extend into the bores of the main jets. Take a look at your carbs in your manual. To optimize the idle and mid-range these will need to be made smaller (thus enlarging the area of the jet), probably. But this scheme is easier than modifying internal passages and orifices like if it were a Holley.

But all in all, doing what was previously discussed will get it to run. Modifying the needles will come later.

Reading spark plugs will be a task that is hard to learn and harder yet to explain, especially w/alcohol fuel. There are a few good articles on it, I will look for them when you get to that stage- and might be a section in your manual, depending on which one you have. It will be necessary to learn, unless you can also invest in a wide-band O2 sensor and supporting soft/hardware.

Might want to look into a top-end lubricant, also. It's used much like 2-stroke oil- that is, added to the fuel. It will help to protect from mis-tuning until you get it dialed in, then you can stop using it.

This is getting OT, but I'll leave it to the mods as to whether it needs to be moved or taken PM.

Please post any ideas you have that may help, whether it be about converting it to EtOH, experiences you may have had with alky or any other kind of alternative fuel, ideas about capturing the heat lost through emissions/engine casing.

Stay tuned for progress updates, pictures, plans and results.

[Bugger]

What grade of alcohol are you going to use? Because of the approx. 90% ethanol-water constant-boiling azeotrope, purification beyond this ("grain alcohol", which itself requires a distillation column with a fair number of theoretical plates), by either redistillation with benzene or use of a hygroscopic dessicant, is costly. The presence of a significant amount of water, and the possibility of ionic solids (such as common salt) dissolving in the fuel, means that anything made of mild steel (including the fuel tank) with which the alcohol comes into contact with is liable to rust, and will need to be replaced by stainless steel, or by aluminium if you can be sure that the oxide layer will not be attacked by acid combustion products and that the aluminium will not be melted by heat given off in combustion.

While the use of a reinforced teflon fuel line is a good idea, it may be significantly more costly than possible alternatives. As regards compatibility of various materials with alcohol, see section 23 of Perry's Chemical Engineers' Handbook, which I have uploaded to rapidshare.com and posted the link in the references section.

[Cobalt.45]

Your concern in re the cost of Teflon fuel lines is duly noted.

In the case of a "go-kart"- type conveyance, we can assume that the fuel lines will be short- thus the expense could be absorbed. But certainly there are other lesser-quality fuel lines that could be used. But assuming a rear-engine, central-driver location, I would insist on the BEST fuel lines including AN fittings (no hose-clamps) due to the proximity to the operator. If the build includes a firewall between engine and driver, this wouldn't be quite as necessary, but why scrimp on such a critical component? The lines used for testing and tuning on a test stand could be of a lesser-quality alky-resistant hose. SS reinforcement and Teflon lining need not apply.

Aforementioned fuel lube/treatment, about $10 for enough to treat 20 gallons of fuel. Would be discontinued once a safe tune was achieved: http://store.summitracing.com/partdetail.asp?autofilter=1&part=RED%2D41102&N=700+115&autoview=sku

DoE site: http://www.eere.energy.gov/afdc/e85toolkit/specs.html provided the following:
"In general, zinc, brass, lead, and aluminum are sensitive to high-blend alcohol fuels, and fueling system components containing them should be avoided. Plated steel (referred to as "terne-plated," a lead-tin alloy) and lead-based solder are not compatible with E85. Other materials that may degrade in the presence of high-blend alcohol fuels include natural rubber, cork, leather, polyurethane, polyvinyl chloride (PVC), polyamides, methyl-methacrylate plastics, and some types of thermo and thermoset plastics."
While this info is concerned w/E85, I believe it holds true for alcohol in general.

If less-than-dry alcohol is to be used, this should be tuned for from the start. "Wet" alky runs hot because the water displaces fuel- lean combustion, although some water might well reduce combustion temp. I do not know at what percentage "wet" becomes "too wet". Water-injection systems add water to reduce combustion temp. from an already "ideal" F/A ratio (stoich for ethanol is about 9:1), and is introduced as a mist upstream of the fuel delivery. Not the same tuning-wise as wet alky.

Why did I think alcohol could be distilled to at or very near 100% (200 proof) w/o elaborate measures? Ya learn somthin' new every day!

[Cobalt.45]

Sorry for back-to-back posts, but I was wondering by what means was the alcohol to be obtained?

Altering the engine to run on alky is no-doubt doable. The fuel itself (assuming it will be made in-house) seems to be a bigger stumbling block.

Do you think making the fuel should be addressed before too much time, energy and expense is spent on the engine?

[Alexires]

No problem Cobalt.

The EtOH obtained will be approx. 85%. If you see the alternate energy thread, you will find a ballpark figure that I wrote up regarding EtOH production. Of course it doesn't include costs related to distilling the EtOH, but that was going to be a side project - making a solar still for EtOH.

As it is, I have the means to obtain the fuel that we will be working with, so all that needs to be done regarding fuel is to make a solar still.

I was planning on replacing the tank with HDPE or with stainless tank, but at the moment I am more concerned with actually getting the engine running. The details can be worked out later, in my opinion.

Find attached to this post a schematic of the carbs that I am going to alter. The highlighted items are the things that are going to need to be mechanically altered.

[Cobalt.45]

The scan of the carbs will be very helpful! For those w/o WinRAR, a free trial version is available here:http://www.rarsoft.com/download.htm

The needle and seat that controls fuel flow into the float bowl is #24. If the tip of the needle valve is viton, I believe it will hold up to alcohol. The inlet orifice may need to be enlarged, maybe not.

The needle I referred to in my second post is #10. It is held in place by the c-clip #6. The needle rides up and down with the piston, #11, varying w/throttle setting. Earlier carbs had several positions that the clip could be placed in, thereby raising/lowering (enriching/leaning) the a/f ratio. Judging by the schematic, yours does not offer this feature (it was phased out due to EPA/CARB (CA Air Research Board) concerns sometime in the 80's, IIRC.

BTW, your carbs are what is known as "CV" or "constant velocity" carbs. They work like the vacuum secondary side of a Holley, i.e. they open by demand from the engine and are dependant on a vacuum signal from the intake tract to sense what the engine will be able to take, throttle-wise. This prevents too much throttle, too early- which could cause the engine to sputter and hesitate.

A decent chart that shows the various drill bit diameters is linked below. They can be used as gauges to measure, and as drill bits to enlarge, the various jet orifices.

Drill bits come in different sizes, with different ways of designating them. The smallest are "numbered" (where you will be working), next are "lettered" then comes metric (4mm, 8mm, etc.) and fractional sizes (1/8, 1/4, etc.) Wiki has more: http://en.wikipedia.org/wiki/Drill_bit_sizes#US_number_and_letter_gauge_drill_b it_sizes

http://www.ngksparkplugs.com/tech_support/spark_plugs/index.asp?mode=nml has an overview of spark plugs, Page 3 shows a few examples of rich/normal/lean plug appearance. A proper search will no-doubt shed more light on this subject.

[Cobalt.45]

In the event someone trips into this thread and is contemplating converting a gasoline-fueled engine to run on methanol, pls. make note of the following tidbits:

Best max-power A/F ratio for methanol is ~ 5.5:1 (stoich is ~ 9:1) as opposed to ~ 12.5:1 for gasoline (stoich is ~ 14.7:1). Ratios are expressed w/w.

Typically, static compression ratio can be upped as well- this will contribute to additional torque (and subsequently, more horsepower), especially at less-than-redline RPM's.

Alky fueled engines can be bastards to get running from cold. They necessarily will take longer to reach optimum operating temp, more so (obviously) in cold climates.

In hot weather, they can suffer from vapor lock and fuel "peculation" when temps are high and the carbs/float bowls have become heat-soaked.

Interestingly, much of the severity of these probs. are not seen w/E85 fuel blends- at least they've not been reported in the performance industry, which is where my primary interest lies.

This post will be a wrap for me. In the off chance any additional info is wanted, feel free to PM me if you think I may be able to point you in the right direction.

G'luck!

[Alexires]

Well, after a rather long period of inactivity, I have found some free time to run some calculations and work out (theoretically) what kind of modifications I need to make to the jets.

Seeing as I hope this will eventually turn into a how to, find attached the calculations I did. If you find errors, post them. If you don't understand something, UTSFE then ask.

Basically though, I ended up with this. I need to increase the flow rate of the jets by about 1.745 units (74.5%). This would translate to a radius increase of about 1.71866 (71.87%)....if the viscosity remained the same.

This is all well and dandy, but the problem I am having is I have no idea what the flow rate/diameter of the jets are at the moment. This website (http://roadstarclinic.com/content/view/61/96/) says that mikuni carburettors have the flow rate, not the diameter stamped on them.

Here lies a problem:

See, as the flow rate is proportional to the fourth power of the radius of the tube but INVERSELY proportional to the viscosity, a 115ml/min flow tube gives 575ml/min of EtOH. So we should ideally make the jets smaller.... What the fuck? Also the other issues are that the designations for the other jets are alphanumeric, so obviously not diameter or flow rate. Fortunately, the numbers are stamped on the jets, but I would prefer to get confirmation before I start buying/drilling things.

Does anyone know the diameter/flow rate for the jets in question? (Will be Main Jet, Pilot Jet and Needle Jet).

I have found this (http://www.sudco.com/vol33/60.pdf) for the Needle Jet which seems like a good resource. If the flow is stamped on the Main/Pilot then we are all set for the next step.

Edit: I have looked over it again, and it still seems right. I have uploaded the attachment again with the checked equations at the end.

[Alexires]

Have double checked the calculations and reupped them. Still telling me that I need to reduce the jet size.....

Edit: Alright, I just ran the calculations for Methanol instead, and it is still telling me to reduce the jet size, which is bloody well wrong. I've fucked up somewhere, but I don't know where for the life of me. I'm just going to drill out the jets following this website (http://journeytoforever.org/biofuel_library/ethanol_manual/manual3.html) and pray for the best. I hate that idea, but shit happens and it seems the only way forwards at the moment.

[Cobalt.45]

You might try using a numbered drill bit set to use as both gages and the bit to enlarge the orifice. Match the current jet size to a bit. Measure it, then compute the size needed. Then match this to the nearest bit from the set. A decent numbered bit set will cost you ~ $10.

Some Mikuni carbs have emulsion tubes as an integral part of the jet, IIRC. If so, there may be more to figuring the sizing than just enlarging the central jet orifice. I don't have access to the carb doc you posted earlier- the trial expired for the software. Any chance you could redo it in a PDF?

I've invited Yamfot to join the discussion- should be interesting.

EDIT- I haven't looked at the formula you're using to compute the jet size, so this is just an idea. Try running the numbers w/o the viscosity as a factor, and see what you get. Flow rates and viscosity aren't generally required unless you were going to design a fuel metering system from scratch. In the case of modding your engine, most of the work has been done already. Enlarging the path for the alcohol is "all" that is needed (talk about over simplified!)

[Alexires]

I thought that might be possible, so I ran it by a physics professor I know. He said my calculations were fine, so fuck knows what's with that. All I can think of is that perhaps the flow is not laminar, so I can't apply Poiseuille's equation to it.

If the viscosity isn't included, we end up with a 15% increase in radius which corresponds to about a 32% increase in area. That is in the same (large) ballpark of the 25% figure quoted in the article.

I have already set in motion getting the jets measured via the numbered drill bit method. As I'm waiting on someone, if it takes too long I'll just buy my own set.

From what you have said, I'm guessing that the jet is tapered in some carburettors to change the flow dynamics at different pressures. If this is so.....it makes things rather hard. But perhaps I will deal with that if it comes to it.

Surely it is no hassle if the jets are tapered or straight? The effect should still be roughly the same. If it becomes a cluster fuck, I can always get a new set of carbs that actually have straight jets so I can do the modifications to them.

I look forward to hearing Yafmot's opinion. I'm sure I read something in the rules about someone saying they are an expert in the topic :rolleyes:.

[Cobalt.45]

The jets flow because of a less-than atmospheric signal in the venturi, so ambient pressure is what "pushes" the fuel out of the fuel bowl and into the discharge port. So what I'm struggling to say, is that there's no real "pressure" driving the fuel flow through the jets (as in pressure from a pump). And therefore that doesn't need to be factored in (in this case), nor does viscosity need to be considered as I said earlier.

A jet is designed much like a rocket nozzle- convergent/divergent cones w/a set orifice diameter, so no, there's no hassle w/enlarging them. The D&C cones stay exactly as-is. The orifice gets drilled, that's all. Just deburr the hole and it'll be fine.

I wish I could lay hands on those carbs to get a better picture of what you're dealing with. I have a set of 4 carbs- from a Suzuki, I think. Don't even remember the size or carb make (they were given to me because the guy changed his and didn't need them anymore) but if by chance they're similar to yours, we can scavenge parts from them. As a matter of fact, unless you're on a tight schedule, let me check them and if they are compatible, I could send you the jets so that if you want you can drill them out instead of the ones that came w/your carbs. That way you will still have a set that'll work with gasoline.

As to: "I'm sure I read something in the rules about someone saying they are an expert in the topic ..." You lost me.:o What rules are you talking about?

[Alexires]

I had the jets measured and these are the results (diameter).

Main Jet (21 in the diagram above) - Size: 57 (1.092mm)
Needle Jet (20 in the diagram above) - Size: 39 (2.527mm)

I could not get the measurement of the Pilot Jet because the nozzle size was too small.

Now, the numbers stamped on the jets are around about those sizes. For instance with the Main Jet , the number stamped on the Jet is 115 which, if it is 1.15mm then lies between the 57 drill bit and the 56 drill bit.

The needle jet has 263 stamped on the side which doesn't lay between two drill sizes. But 2.63mm is close to 2.527mm.

The best guess I can do with that is: Use the number stamped on the side, so at least I have a measurement for the Pilot Jet (17.5) and just drill them out according to that.

That makes the new nozzle sizes (diameter)

Main - 1.29598mm
Needle - 1.4931992mm
Pilot - 0.19721mm

So probably the best bits to use for the job would be...

Main - No. 56 - 55 (1.181mm - 1.321mm)
Needle - No. 54 - 53 (1.397mm - 1.511mm)
Pilot - Uhhhh. Nothing goes that small. Either use the smallest bit and dial it lean as, or just try and dial it out as it is till its rich....

Otherwise, I could just buy another Pilot jet that is about that size...

Thoughts, suggestions?

[Cobalt.45]

The diagram for #20 and #21 isn't showing up...

The pilot jet works out to be an impossibly small .00777". You're certain that this is correct?

The smallest commonly available bit in the number sets I have is #80 = .0135" (.3429mm). This is obviously tiny, I fear anything smaller would be too hard to work with without breaking!

Keep in mind that if drilled too large, the jets can be soldered shut and re-drilled. This isn't a solution you'd want to use for a "production" set-up, but for tuning, would be acceptable.

When working with these small bits, great care must be used if using a drill motor. Usually, a "pin vice" is used, so the holes can be drilled by hand.

[Yafmot]

Let me tell you guys a little story. Back in the middle of the '70s oil embargo, gentleman by the name of Bill Paynter had an aviation operation at Sacramento Executive Airport. Union Flights did just about everything an FBO (Fixed Base Operator) can do except flight training. Part 135 (Air Charter/Taxi), maintenance & repairs, engine overhauls, and had a transportation contract with the State of California to fly various govenment bigwigs anround (Billy was Reagan's personal pilot back when he was governor). In WWII, he was a B-25 instructor and then switched to flying B-29s out of Tinian. After the war, he went to work as a lineman for the phone company. In the course of this work, he noticed that he was spending an awful lot of time repairing lines that were dug up by errant backhoe operators, well drillers etc. He got the idea to patrol these miles of trunk and smaller lines from the air, using map overlays. When the phone company took a look at the cost of the problem, they agreed, and told him if he would go out and buy, maintain and operate the aircraft, he could have the contract pretty much in-perpetuity.

So, with a letter of intent from Ma Bell in hand, he went down to the bank and secured a loan sufficient to lease a hangar, hire some pilots and mechanics, secure the necessary accouterments associated with a flying operation (tools, jacks etc), and about a half dozen Piper Super Cubs. These aircraft were selected for a combination of simplicity & ease of maintenence, economical operation and slow flight capability coupled with reasonably high cruise speed to get to each day's patrol area.

And the years went by, and he picked up contracts with PG&E, various pipeline companies and several local utility districts. Then he picked up contracts from Fed-Ex for a bunch of their smaller routes, and bought a fleet of De Havilland Caribous, big, twin engine transports with P&W R-2000 radials that you can get up and walk around in. And interspersed between all this, he expanded his Part 135 operation, running everything from Cessna 182s & Piper Comanches to Twin Comanches to Beech Dukes & King-Airs, culminating in the addition of several models of Cessna Citation jets (and I think there were a couple of Lears in the mix, too).

But when the oil embargo hit, it was the Super Cubs with the biggest fuel bill, because even though the other aircraft consumed more fuel individually, they were only operated sporadically, as the need arose. But the fleet of Super Cubs had grown to over a dozen, and they were in the air all day, every day.

Avgas had always been more expensive than Mogas, and now it was through the roof, and to say Billy was getting pissed off would be a gross understatement. Enter Mr. Gordo Cooper (yes THAT Gordo Cooper). He and Bill had been acquainted for some time, and while it was not generally known, he was a dyed-in-the-wool, black belt motorhead. He had been involved in the development of several race motors, including Indy stuff, which had been operating on Methanol for a few years (ever since the Swede Savage crash).

Billy knew that gordo was well familiar with the intricacies of burning Methanol as a motor fuel, and also that it was way cheaper than Avgas. So he gives him a call and ask if it's possible to reliably run a Lycoming O-320 (a simple, basic 320 cu. inch 4 banger) on alcohol. Gordo says it would not only be possible, but that Methanol would likely be far superior to gasoline in an aircraft engine and, in fact, he'd been studying the idea for some time.

So they pulled one of the Super Cubs off the line, pulled the engine, rebuilt the carburetor with Alcohol-compatible seals, drilled out the jets to flow 40% more, advanced the timing to something ridiculous like 40 before, and gave Lycoming a call. When they asked the engineers if they thought it would be okay to run that engine on Alcohol the way they'd set it up, the Lycoming guys said "No, don't do it! You'll just blow it up." A little bit taken aback by this statement, Gordo said "Well, Methanol has a slower pressure rise time, a slower temperature rise time, lower peak pressure and temperature, a much lower flame front speed, and an equivalent Octane Rating as high or higher than purple gas (120-135). So why would it "blow up?"

Lycming, saying nothing specific, reiterated "No, you'll just waste it." Deciding that the engineers were just doing a little CYA, to keep their asses out of the sling with the legal department, they took the motor down the street to the Sacramento City College Aeronautics Department (one of my alma-maters) where they had a fully instrumented test cell. They hooked it up and began what was planned to be a 72 hour run. They ran it in every concievable mode and configuration they could think up. They had installed a prop governor on it to run a variable pitch prop, and they would run it at full throttle with flat pitch, full pitch, both wth carb heat, part throttle with same conditions, then go through the same thing on the edge of lean stumble (in most airplanes, mixture is cockpit controllable), and then run through the drill again while rich loading it, all the while taking notes on all instrument readings and control settings. They also had a strip recorder/datalogger to get the readings vs. time and to check against the hand notes.

Well, the run may have been scheduled for 72 hours, but after running it through every combination of conditions and configurations they could think up for about 48, everybody had gotten sick of listening to the damned thing. They had been through all the drills several times, and had gotten just about all the information they could hope to glean from the data they had collected, which was mostly favorable and per their predictions. So they shut it down pulled it from the test cell and hauled it back to the hangar. When they tore it down, the pistons were clean enough to eat off of.

Having anticipated favorable results, their crew had removed the tanks, "sloshed" them with a protective coating, and installed alcohol compatible lines & seals in the rest of the fuel system. While the engine was being reinstalled, they called Lycoming back to see what they thought about flying it on methanol. Predictably, the Lycoming guys said "No no no! You just got lucky. You'll never get it past 4,000 feet, and if the fires go out, you might not get a restart." Bill & Gordo were starting to get amused. They asked, "Why not? It packs along some of its own Oxygen. Everything we know about Alcohol combustion would suggest that it would run better at altitude." But Lycoming stuck to their guns. "Don't do it. You'll just dig a hole."

Deciding to find out for themselves, they put the plane back together. Gordo grabbed a portable O2 tank & mask, climbed in, and took it up to 18,000 feet, about 5,000 feet higher than the published service ceiling. At this point, they didn't even bother to call Lycoming, except later on, just to rub it in a little.

During this period, they hooked up with a guy by the name of Chuck Stone, who owned a company called Alcohol Fuels of America. They started another company, named Alcohol Aircraft Fuels which, as the name implies, developed alcohol fuels for aircraft. With this partnership, they started looking into the conversion of other aircraft engines, and they set about the business of getting an STC (Supplemental Type Certificate) for the Alcohol Super Cub conversion. And as anyone who's ever tried it can tell you, getting an STC is a process not unlike banging your head against a brick wall. Repeatedly. HARD.

Our dynamic duo would travel all over the country to various conferences, symposia and the like on alternative fuels, and at the most "important" ones (Society of Automotive Engineers, Society of Petroleum Engineers, various government conferences etc), there was always some overeducated idiot there to say they couldn't do it. This was usually when they had flown the Super Cub to the conference, and they delighted in giving back smartass responses such as "Well, I sure wish you would have told us that earlier. Now we've got to rent a flatbed, pull the wings off, strap it down & drive it all the way back to California." The doomsayers would try to feign incredulity but, in fact, would be embarrassed all to Hell.

And at every one of these enclaves, the "experts" would be saying that Alcohol lacks the caloric content to be a viable fuel. Billy told me "They're all stuck on BTUs, BTUs, BTUs, and can't think beyond that." Fact is, it's not just caloric content that determines a fuel's performance, but the amount of EXPANSION PER BTU. With gasoline, or diesel, for that matter, the fuel is simly there to heat the working fluid, which is the Nitrogen in the air, the oxygen being used to react with the fuel. Thus, it's the Nitrogen that's doing all the work. With Alcohol, water is also formed, so you've also got a little superheated steam going to work in there, which more than makes up for the lower heat input into the Nitrogen.

Well, somewhere along the line Chuck Stone bailed (I think he got sick), and Bill & Gordon reincorporated as XL Inc. This was also because they had finally gotten the STC for the Super Cub conversion. In many peoples eyes, Gordo deserved a medal more for wearing down the Feds than for any of his space flight accomplishments. The FAA had simply run out of reasons to say no. They also began work on converting the Pratt & Whitney PT-6 turboprop engine to run on Alcohol. They assumed, correctly, that the same expansive properties that worked so well in a piston engine would also work in a tuboprop, or turbofan for that matter, though less so in a pure jet.

XL was situated on Stead Field, just North of Reno, where they have the Air Races. They had an old bus with the rear half of the body removed. They put a flat bed on the rear chassis, an engine mount and dyno brake on that. The forward part of the cab was mostly a control room, with instrumentation hooked to various sensors on the engine. They'd drive it up Peavine Mountain, the summit of which was about 11,000 feet, for testing at a somwhat higher altitude. And in the summer, the Density Altitude could get up to 15,000.

Then that operation was joined by another company they started, the Galaxy Group. They were designing, and trying to certify, gas turbine conversions for various aircraft, the Aerostar being perhaps the most prominent. This was done with an eye toward running them on Methanol as well. As a completely unrelated sideline, one of the people on board brought along an operation specializing in Deep Sea submersibles.

Sadly, Billy gor sick, in the late '90s, with Pulmonary Fibrosis, which seems ironic when I think about how he used to bug me for smoking cigarettes. We lost him in '99, and five years later we lost Gordo, who was sometimes introduced as the last American to go into space alone, on the same day that Brian Binnie clinched the X-Prize for Rutan & co. by...going into space alone.

The point I'm making is that here were two guys with a ton of "horsepower" between them, and even under the dire conditions of the Arab oil embargo couldn't quite sell a perfectly valid concept. And this was before the phony baloney boogie man that is "Global Warming." (If you believe that "Anthropogenic" shit, then I've got a great deal for you. No checks please; cash in small bills.)

I just might see if I can chase down the papers & data they amassed over those years. They had documents dating back to the WWII Lufwaffe's studies on Alcohol & water injection (which is still in use at the above-mentioned Reno Air Races). Plus a lot of good stuff they accumulated in their own program.

I'll be coming up with some tips & tidbits shortly. I've got a bunch of my own old material, too. Just gotta' dig it out.

[Alexires]

The diagram for #20 and #21 isn't showing up...

The pilot jet works out to be an impossibly small .00777". You're certain that this is correct?

The smallest commonly available bit in the number sets I have is #80 = .0135" (.3429mm). This is obviously tiny, I fear anything smaller would be too hard to work with without breaking!

The diagram I am talking about is the one posted way above (http://www.roguesci.org/theforum/showpost.php?p=99298&postcount=5) that is a scan of the workshop manual.

Yes, I know that is impossibly small. It is too small to take a measure off, so I had to guess with that one. I simply figure that I will first try dialing it out so that it is rich as fuck for petrol and try running EtOH in it. If that doesn't work, then I will drill it out with an 80 and dial it in lean. If either of them don't work, I'll just buy another pilot jet in a bigger size.

While it would be ideal to be able to do it all yourself, the jets we are working with are just too small. If I had an old car engine, that would be ideal. But I don't so we will work with what I have.

Looking at the hole, it is tiny. About the size of a wire from a wire brush.

I could do it myself, but I'm going to get a friend to do it. He is a fitter and turner by trade, and now works for a company that manufactures lasers for eye surgery. If he can't do it, then I don't think there would be many people that can.

Yafmot - I encountered that the other day. I rang up some tuning specialists to see if they had the diameters for the jets, and we spent 10 minutes with him saying "You can't run it on Ethanol, it would be like pouring Bourbon into the engine!" and with me saying "I just want to know the size of the jets".

There is going to be some trial and error here, that is expected. I expect it not to work the first time. What fun would it be if it did?

[Cobalt.45]

What are the ID/model numbers from your carbs? They will be stamped into the casting. From that the throat or venturi size can be determined (like 28mm, 32mm, etc.).

This site shows all the Mikuni jets and the range that their available in: http://www.carbparts.com/mikuni/mikuni_tuning.htm

Richer pilot jet could actually be a good thing- it richens up the A/F mixture across the board, from idle to WFO. The air mixture screws fine-tune the pilot jet, so if the pilot is larger than needed, the screws can compensate, within reason.

The following was found on a site for ATV’s, but pertains to bikes as well: http://www.ctracing.com/alcohol.htm
Reminds one to “Tune from the bottom up. Dial in the slow circuit (this will be the Pilot Jet on your carbs) and air screw first, then the needle and clip position,then the main jet”, etc.

I don’t want to go and just list a shit load of sites, we’ll just take things a step at a time and keep things in order as best as we can. Starting with the low-speed circuits first.

Part of the problem is that for high performance use, your “CV” type carbs were usually swapped for a set of “flat-slide” type carbs. The flat-slide carbs flowed better and weren’t hampered w/the vacuum-dependant feature of the CV’s. This only means that there probably won’t be any specific info available on your exact carbs.

But I concur w/your earlier observation- what fun would it be if it were cut and dried w/no experimentation?

Hell, ANYBODY with the means can throw money at a problem. Truly motivated individuals will use their minds to solve a problem, often with excellent results and at little financial outlay.

[Alexires]

To all following this thread. I'm not going to be able to do much on the project for the next 4-5 weeks or so. I'll let you know when I have an update.

[Yafmot]

Hey, Alexires, I've got a POC at Mikuni I could send you to that could probably answer any questions you have about their products. Just PM me and I'll give you all the particulars. I'll also try to track down the guy from Monterey who flew an ultralight from there to Oshkosh, converted it to ethanol at the show, and then flew it to Kittyhawk on alcohol. Two strokes love the shit, as long as you use compatible oil. Synthetic works best with alcohol, and the combination of cool burning fuel and the extra film strength of the lubricant means you could ride it through Death Valley in July with a next to zero chance of seizing the rings or anything else.

Speaking of which, I've seen nothing in this thread that has indicated whether your bike is a two stroke or a four. One lunger or two. This makes a difference.

I'm also going to look up an acquaintance who has a company manufacturing throttle body injectors for ultralight engines through Pratt & Whitney R-985s. They're all pretty much the same, proportionally, just sized to the application. The way they work is there's a single barrel with a slide, much like a motorcycle carb or an SU, except that the slide is rectangilar in section, with a semicircular notch in the bottom end so the whole bore goes to WOT all at once, and also so it won't completely close. The slide travels on a hollow, central pin with a series of small holes on one side, through which the fuel is delivered. As the slide moves up to open the throttle bore, more of the holes are exposed. The pin can be rotated, facing into the airstream to lean it, or away to richen, and is infinitely variable & cockpit controllable.

This means you can plumb the fuel feed to immediately switch from alcohol to gas. You can have a small header tank with gas in it for warmup & emergencies, and alcohol in the main tank(s) for the bulk of the work. This could be a real blessing on long trips, where alcohol might not always be available, or in really cold weather, where you can just about wear your leg off trying to get the thing to pop.

Couple of other things. First, you'd do well to install as hot an ignition system as you can find. The stuff can be a little harder to light off than gas. Second, be careful with your mixture and timing, but not for reasons you might think. It's actually possible to
detonate a very rich mixture(!) if the timing is advanced enough and other conditions are right (temperature, compression etc). Gordo cooper was telling me about the first days of alcohol fuels in Indy cars. He said they managed to grenade several engines with the stuff before they got it right.

I'll be posting other stuff as it comes to mind.

[Cobalt.45]

...I've seen nothing in this thread that has indicated whether your bike is a two stroke or a four. One lunger or two.4-stroke, I want to say 360 degree, twin cylinders. Two Mikuni CV-type carbs, size unknown.

DOHC, don't know off hand what the valve timings are. Red line is around 10K, HP and torque at what rpm isn't known by me, but can be found easily enough if needed- prob. in the manual that Alexires has.

Might have a CD-type ignition system from the factory, upgrades are easily enough accomplished if not. We were strapping car coils to the downtubes of the RD-series Yamahas back in the '70's to overcome their weak points-type ignition systems that often allowed the cold plugs we used to foul; a similar set-up might be used on this build.

[Alexires]

Cobalt has the measure of it.

Thanks for all your help, you two. I look forward to getting really stuck into it in 2-3 weeks (trust me, I'm counting down). Already have a fitter/turner lined up to do the carbs, so they will be schmick.

Any suggestions what to do about the smallest jet? Should I try and dial it right out and see if that works? Or just drill it as small as I can, then dial it right in?

That would be good if you could look up that trip, Yafmot.

[Cobalt.45]

There are many different sized pilot jets available, this might end up being one part that's better purchased, than made.

The problem I see w/drilling out to even the smallest available drill size, is that the mixture is effected all the way from idle to WFO. If it's fat down low, idle will suffer as well.

[Alexires]

The problem I see w/drilling out to even the smallest available drill size, is that the mixture is effected all the way from idle to WFO. If it's fat down low, idle will suffer as well. Yeah. What I might do is leave it and make it as rich as possible. If that fails, I'll drill it. If that fails, I'll buy a new jet.

What I am aiming for with this project is something that other people can look at, and do themselves with little difficulty. It is all well and good to go buy everything you need, but that is lame and defeats the point as far as I am concerned.

As a fellow hobbyist I know you understand that, it was just more for others reading this.

[Cobalt.45]

Good plan. Also, the idle adjustment screw might be able to compensate for the additional fuel needed. The screw works w/the pilot jet to control A/F mixture at idle.

After looking at the carb diagram again, I see there’s a pilot air jet (#58), located in the mouth of the carb.

If this were to be peened or brazed shut (don't know about using solder w/alky fuel, for long-term durability) then re drilled to a smaller size (less air = richer mixture), this should in theory work to enrichen the A/F mixture for that circuit.