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Dubkustom, I sent you a couple of messages but they came back, in any case I put together a list of things I could remember regarding the ethanol conversion. Hope it helps. If I can help in any other way, let me know.
I'm not a chemical engineer, the VWs are mostly a hobby, so I can talk about my experience and along with it I'll tell you a bit of the story so you understand.
In Brazil we have a blend of ethanol which is called hydrated alcohol. I don't know how it compares to E85 in terms of corrosion potential. Ours is probably more corrosive since it has water added to it.
It started in Brazil around the mid seventies. At first the cars were troublesome and worst in every way. Slower, worse mileage and so forth. Corrosion was also a problem.
They got better along the way.
So, regarding corrosion. It attacks every part that is in contact with it, but it is really serious in the carbs. Meaning that if you leave everything alone (and parts of it, there isn’t much you can do, like the gas tank for instance), except for the carbs, you should be fine for a long time. All the Brazilian cars started having corrosion protected fuel systems around the 90s, even the gasoline fed cars.
There were factory alcohol beetles, but I could not supply you a list of alcohol specific parts, except for which I remember, the carbs were specific, the pistons and the heads (for compression ratio reasons).
My car is converted and the following is a what I know about using hydrated alcohol to run the cars (it applies to everyone)
Gas tank: There isn’t anything you can do with the factory tank. If the tank is in top condition, corrosion will show its face after many, many years. It is not a problem though. Later the cars started using plastic tanks. The beetle never had a factory plastic tank but there are some companies making them today. My car does not have one.
Lines and connections: Regular rubber hoses and copper fittings. Since there is less oxygen in contact with them (when the alcohol dries, which it never happens in the lines), corrosion and oxidation does not take place.
Fuel pump: It has to be nickel plated (factory ones were like that)…or some other sort of corrosion resistant plating. However if they are not like that, they will show signs of corrosion after some time, you would be able to run a normal pump for a long time. An option is to use a modern EFI pump with a fuel regulator. My car has an EFI pump from a Opel Kadett. They last a long time if the cars is in constant use (constant in the context of the subject is at least 3 times a week)
Carbs: Likewise nickel plated. It will work without plating if you drive constantly. Allowing it to sit will produce a gel in the carbs that clogs up everything. Eventually it will fall victim of corrosion itself. My carbs are nickel plated. Simply took them completely apart and had them plated at a local chemical shop. The brass and copper parts are not plated, like the throttle plates, needles, jets and so forth. Just the casting.
SO in other words, for a daily (I mean daily) driver, if you re-jet they run, and eventually you will see corrosion after a couple or years depending on the condition of things. If you do not drive it as often as 3 times a week, you will see constant clogged carbs. If you nickel plate the carbs, you will see years of trouble free use as long as you drive at least once a week or so. Eventually other things will corrode, like the pump.
Modifications to the rest: The engine needs a higher compression ratio to fully use the potential of alcohol. Ranging from 10.5 to 1 on a factory 1600 beetle to 14.5 to 1 on my engine for example. What determines that is basically how much cam you have in the engine. Consider 10 for a factory cam and 14 for the wildest cams currently available. I run a 313 degree Engle.
It needs a different timing curve. There is less initial advance and less final and the range is a bit narrower. There is some modification needed to adjust how much advance the distributor will have. Timing is dependant on what you run on the rest of the engine, cam, CR, size of the carbs, how rich or lean you like to run the car. My car runs 14 initial and 32 final, if it ran on gas (and had a considerably lower CR – like 9,5 or 10 max) it would probably see something like 16/40. Rule of thumb is to watch head temp and knock. You might want to play with it a little.
And finally, it needs more fuel. Roughly 30% more. It is good (depending on engine performance it is essential) to step up to bigger float needles. Factory being 150 you would need at least a 220 or bigger. I run 300s on my Weber 44s. And a fuel pressure of 0.4 bar. A factory pump won’t provide that much. So the EFI pump is needed on hotter applications.
Iddles are bigger and main jets as well along with less air correction.
The emulsion tubes are also different, as well as the venturis. Original Weber 44s comes with 36mm venturis. I run 34 venturis. The smaller the easier the car will be to tune, the larger the more power (up to a certain level) you will make if the rest is right. There is very little change in my car while running 36 venturis, but it does make more power and loses some drivability.
Emulsion tubes are richer, usually simply by being of smaller diameter and allowing more space and therefore more way for fuel. I use F3 in my Webers instead of the original F11. They are identical, except a few mms skinnier on the outside (maybe two, I cannot remember right now)
Just to give you a ball park: I run 90 idles, 170 fuel, 170 air. If it was gas, it would be 60 idles, 140 fuel, 200 air. Something like that. Since air and mains have interference on band, from 3000rpm up to 5500 is mains and from that on is air (and up to 2500/3000 is idle), it is really a matter of what the engine has in terms of equipment. My advice is increase idle and mains by 30% and start by running the engine only up to 2500rpms, get the idles roughly correct (allow longer time for the engine to warm up though), then step up the revs, running from 2500 to 5000. add and subtract in increments of 5. Then use the whole band and play with air. It has to run flawlessly, if it does’nt, it is not done.
My setup allows for a slightly rich idle and not so rich top band. I think this provides crisp response and yet is lean enough to wind up to 7300rpms. If I run richer in the whole band with alcohol, like a gasoline engine would allow, it doesn’t seem to like the revs that much. Alcohol doesn’t like rich that much.
Oh, last thing, spark plugs, should be colder. While a gasoline would use NGK EGV 5 or 6 (depending on original or hopped up), you can run EGV 7, 8 or even 9 (10 also) on an alcohol engine. I run 7. No change in running colder than that. If it was a turbo application, the colder the better.
One more, filters should be plastic or stainless steel, not the regular metal ones (corrosion again). Generally where you can opt for plastic or rubber or stainless steel, go for it.
I hope this covers most of it. Please feel free to contact me at any time regarding this and other matters.
Enjoy!
Regards, Marcelo
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