Conversion Questions

Tech about stuff that doesn't fit in the above categories
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flyinggreg
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Conversion Questions

Post by flyinggreg » Sun Sep 11, 2005 10:38 am

With the horrid price of gas I finally decided to take a serious look at LPG.

This site is GREAT, but I can't seem to find a posting to answer the basic question....

WHAT PARTS ARE NEEDED TO COMPLETELY CONVERT FROM GAS TO LPG?

Does anyone have a list?
Is there any difference in parts between a dual-fuel and a complete conversion? Are there any differences in parts between LPG & CNG? Is it true that lower gas economy can be found on a dual-fuel system and better gas economy on a complete conversion? Does Santa Claus and the Easter Bunny exist?

Thanks for the replies!


C3H8
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Conversion parts

Post by C3H8 » Sun Sep 11, 2005 10:53 pm

You don't mention what type of vehicle you have but for most vehicles the parts are the same except for the mixer. The type of vehicle you operate might also limit your choice of manufacturers. A basic kit is comprised of 5 main components.
Tank: This should be an ASME approved tank for over the road use and installed according to Federal and State/Provincial regulations.
Lock Off: This can be electric or vacuum. It shuts the fuel off whenever the ignition is turned off or the engine stalls.
Convertor/regulator/vapourizer: This takes tank pressure and reduces it to a basic usable pressure prior to entering the engine. This part also turns the liquid LPG into a vapour.
Mixer/Carburetor: Used to mix the fuel with air just before entering the engine. The mixer is designed for the specific size of engine it has to handle. Adaptors are needed to fit the mixer to specific engines.
Hoses: For LPG you have to use an approved Type III hose. This hose has an inner sleeve of teflon, a neoprene second sleeve, a wire braided reinforcing sleeve and is finally covered by a rubber outer casing. It is specifically designed to with stand cutting in an accident. It has to handle up to 250 PSI but it has a burst pressure of about 2000 PSI.

Besides these parts you will need miscellaneous items including fittings (usually brass), switch and relays to shut off your injection system or a gasoline lock off for older carbureted vehilces. If you are converting a newer fuel injection vehicle you should use an electronic box to make the system compatible with your OEM computer.

Frank
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Post by Frank » Mon Sep 12, 2005 10:09 am

WHAT PARTS ARE NEEDED TO COMPLETELY CONVERT FROM GAS TO LPG? Does anyone have a list?
C3H8 gave a good summary in the previous post. As this is a vehicle-specific question, there isn't a generic list. Converting to propane isn't like buying new air cleaner and bolting it on. Also, the basic operation of the vehicle is substationally altered and, if not done properly, can be dangerous. You should not be attempting a conversion without being first appropriately trained.

Is there any difference in parts between a dual-fuel and a complete conversion?
I presume you mean straight or dedicated system when you say complete conversion.

Yes. However, on newer fuel-injected vehicles it doesn't make sense to remove the existing fuel-system because it is an integral part of the vehicle. On these cars, converting the vehicle to dual fuel makes the most sense.

Are there any differences in parts between LPG & CNG?
LPG is stored as a relatively (relative to CNG) low pressure liquid while CNG is stored as a high pressure gas. Therefore, the fuel tanks and regulators are completely different. In addition, LPG requires a converter (which is integral with the regulator) to convert the liquid to a gas by adding heat from the engine's cooling system. Once a low pressure gas, the mixers or injectors could be similar.

Is it true that lower gas economy can be found on a dual-fuel system and better gas economy on a complete conversion?
A dual-fuel system using a dual fuel ECU with timing and mixture settings properly programmed for both fuels should give optimal fuel economies for both fuels. A straight conversion could be more fuel-efficient than a dual fuel conversion if the engine has been modified to optimize propane's higher octane number.

Does Santa Claus and the Easter Bunny exist?
Your children will be better able to answer this than me.

flyinggreg
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Post by flyinggreg » Mon Sep 12, 2005 8:01 pm

Wow! Thanks A LOT for the help!

What I have is a 85 Ford F-350 Crew Cab with a I-6/300 and presently 1-BBL carbureted. I'm looking at finding the time to convert to EFI with a Megasquirt and Megajolt EDIS. I got the manifolds, throttle body, and injectors ready to go. The thing I don't have yet is the controller and the fuel delivery to the injectors. My ultimate goal is to have a turbo'd, EFI, EDIS, single-fuel LPG (or CNG) system. The carb'd LPG would be an intermediate stage.

We are currently located in FL, but are looking to relocate back to OH (we call it hurricane baseball - 3 strikes, and we're outta here). I know winter temps are gonna be a factor.

I am debating with CNG and LPG. I read about using your house natural gas line to refill your car and paying for it on a monthly bill....hmmm, that just sounds too cool. But, if you need different equipment on the car, between LPG and CNG, I think I might just stick with LPG. As far as I know, LPG is easier to come by than CNG - am I right?

Anyone know of a DIY controller like Megasquirt for an IMPCO feedback carb/mixer system?

Still wondering about Santa Claus and the Easter Bunny - no kids :lol:

C3H8
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Conversions

Post by C3H8 » Thu Sep 15, 2005 11:21 pm

1985 Ford I-6 engines make good conversions except for one issue. 300 CI Fords converted between 1975 to 1980 experienced the usual additional fuel consumption of about 15%. For some reason that many were not able to solve the 1981 to 1985 300's could experience dramatic drops in mileage. Some had as much as a 40% drop. The exact reason could seldom be determined. I had customers that tried everything, timing, different cams, intakes, exhaust, etc. but they still had this wild drop. Usually it could be predicted. If the vehicle was getting really good mileage on gas compared to other owners his LPG consumption would usually be excessive. If the owner only achieved average consumption on gas his drop in economy was less.

You want cool. In NW Ontario the NG company, NC Gas, ran Tri-Fuel vehicles. Gasoline, LPG and CNG. They ran CNG in the major cities. If they ran out of CNG they switched to LPG which commonly occurred out of town. If the vwehicle was away from both sources of LPG and CNG and ran out they switched to gas. It was a tricky setup but they worked pretty good.

As for home fueling. It is quite possible with a VRA. This is a slow fuel compressor that is located in garages and slowly fills the NG cylinders overnight. It takes 6 to 10 hours to fill an avergae size NG cyclinder this way. The only issue is you need 220 volt 3 phase electrical hook ups. This means getting a professional electrician to hook it up and it also means using a fair amount of electricity to fill tanks offsetting some of the savings.

Typically LPG stations are much more plentiful then CNG, however some states have a pretty good supply of NG stations. The issues around LPG stations vs CNG are simple. It costs 250K to 400K for a good fastfill CNG station. An good LPG station can be set up for 25K to 50K. A cheap LPG station can be had for 15K to 25K. :lol:

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