Hi all, I've been thinking about building a blown engine for propane. What I've got is a mopar 440 engine, forged 10:1 pistons setup for quench with closed chambered aluminum heads. I have an 8-71 blower sitting on the shelf that I can either use or sell. Naturally I'd prefer to use it but my compression is high for pump gas. I have heard of guys in australia doing blown propane motors but don't really hear much about it in my area. I have a megasquirt fuel injection controller sitting on the shelf also. I was thinking I would use it to control ignition timing for the whole thing(not that I know what propane likes for timing) as well I could plumb in a couple fuel injectors to provide backup gasoline fueling. What do you think? Good idea, bad idea?
Been down this road, just not with an EFI setup. I used old-school mechanical mixers from IMPCO. 350 9.5:1, about 7psi boost. About 30º advance, all in by 2500rpm. Worked well, and as far as I know, it is still out there. You'll probably want to limit to 6-7psi boost, which would be about 15% underdrive on a 440 with an 8-71, for about 14.5-15:1 CR. For the initiated, the octane rating of Propane is 110.
Yes I was thinking to use two Impco 425 mixers. The fuel injectors would only be turned on as a backup so I could burn gas if I run out of propane. I would probably hook the propane up first and phase the gasoline system in a little later. I would think with the propane and blower it should start pretty quick and easy.
Pedal to the floor until it lights right up. It takes a couple of cranks, as it is a vacuum metered system.
Found a local guy who wants to sell me a complete propane system w/ an impco 425 for pretty cheap. Tanks he has are way too big but I have a buddy who will give me a 20 gallon tank for free. How does the propane do with the blower? I've always hear that when running a roots type blower, having carbs on the top helps because the fuel cools the blower. Does the propane come out cold enough to do the job or is alcohol injection advisable? Just throwing some ideas around before coming up with my actual plan.
It's funny you brought this up. I was just reading in another forum that I frequent (OT trucks) and a guy built a propane fueled turbocharged LS powered truck. The truck is a daily driver and goes mid 11s. Not bad for a 4800 pound pig. Check the thread out here: http://www.performancetrucks.net/fo...opane-turbo-5-3-first-track-day-video-507389/
I've seen ads for a company called Alternate Racing Fuels that supplies high performance propane systems. I'm sure there are others that supply EFI propane systems.
Propane is heated to convert it from a liquid to a vapor. If the liquid can be directly injected, it should really cool the blower.
As I recall, even though propane has a higher octane number it takes a larger quan***y of it to produce the same power as gas. That is why conversions use much larger tanks. A 20 gallon tank of propane won't take you nearly as far as 20 gallons of gas. Just keep this in mind as you move forward with your plans-I do like the idea!
Yes, liquid propane injection would be cool (pun intended) but I haven't been able to find anyone who sells liquid propane injectors in a big enough size for any kind of a reasonable price. Looking more and more like the impco 425 mixers are the way to go. I'm sure that with the blower I'll still be able to make all the power I'm looking for. JA, yes I have read that before. At least I'm starting off with a reasonable compression ratio, not 8:1 like a lot of the converted 70's motors were. However like I said, I definitely do want a gasoline backup system.
Too easy. That, and corn puts you straight into food politics, neither of which, food, or politics, are appropriate conversation for this board.
Thought about it but nobody here sells it in my province. Nobody. We grow lots of corn. We have an ethanol production plant. Yet nobody sells or has ever sold E85.
Bruce Crower did some stuff with CNG back in the seventies for San Diego Gas & Electric. There may be somebody still there that could give you info.
Liquid is used to cool and lube the seals and wipers on the rotors. Using stock un-stripped rotors would not be a problem, but dont expect big boost pressure.
Yes but can you fnd E85, aside from being hard to find in a good year, it is corn crop dependent and this year we have an extremely bad corn crop. I have never msessed with blown propane and have not messed with propane as a fuel since the '70s. I am sure that the systems are better theses day, what I recall from the times I had to mess with them was that icing was a problem in the winter. Like I said I am sure that the newer systems are better but it should actually cool your blower real well. I wonder if the blower clearances are different for propane?
The hot rod won't be a winter driver anyway, but like I said, I'm planning a gasoline backup system. Pretty sure my blower does not have striped rotors. I did talk to the guy who built it and he said another gentleman ran one in a fuel injected application with the injectors below the rotors and it did just fine.
How does CNG compare on octane and supercharged applications? I just imagine it is more expensive, input?
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