28 replies to this topic

[s'ko]

I know that LPGSuperchargedbrumby is running propane.

So I did some research and found this write up.

http://www.motherear..._Car_To_Propane

Dual Fuel Gas/Propane engine.

Is this something that is workable? It sounds too easy for a mere 100 bucks or so.

BW

[ThreeEyedBandit]

Subadoom and I are workin on converting a brat over to just LPG. So far it is extremely do-able, and so far are about 100 dollars into it for a used Impco CA-100 mixer and a new model J converter. We just need the tank and fuel lock with a couple little pieces of hardware and it should be up and running.

Matt

[NorthWet]

That article was from 1972... the prices are a little different now. Probably more like $500-1000.

Propane has definite advantages, IMHO.

[mtsmiths]

Do-able, heck it's been do-able since the '50s. Lots of farm trucks were running around on field propane. Usta have little oil injectors to help old-style valves out, prolly don't need those anymore.

[Sweet82]

The nice thing about propane is you can restart your car at odd angles. I have found my Subie won't start on steep inclines or side hills. Propane eliminates this problem.

It's sort of like a poor mans fuel injection.

I'd love to do it on the buggy.
Glenn
82 SubaruHummer
01 Forester

[Ross]

Definitely the way to go - especially if you want more power out of your engine.

[LPGsuperchargedBrumby]

dual fuel works but you get a drop in fuel efficiancy (and power!) due to the restriction of the extra ventury i.e the propane mixer ring
dedicated lpg propane is definatly the way to go

[torxxx]

LPGsuperchargedBrumby you got a write up on how to make you sooby run on LPG? I like the idea of it. How many miles/pound do you get? also

Thanks

[Zefy]

propane is great... my auto teacher has all his trucks running on propane... apparently you get 110 octane rating with the stuff... and its uber cheap... even the school drag-car(a cuda) runs on propane...

the only big downside is the smaller tanks... you can't "fill" a propane tank like you can a gas tank...i believe half full is the norm for a "full" tank of propane...

[LPGsuperchargedBrumby]

there are any number of generic writeups on how to install lpg.
i tee'd into the heater hoses to get the heating water to the regulator and mounted the regulator on a bracket where the spare wheel would normally live, spare now lives in the tray.
carburation is currently handled by a ABER propane carburetor with dual 34mm throttle butterflys, more than that about the carb i don't know as i picked it up secondhand but it seems to be similar in operation to an impco type mixer

LPG MPG is normally about 10-15% more fuel used than on petrol@ standard compression ratio, however a 12.5 to 1 compression will get 10-15% better fuel economy than a petrol that is still at standard comp ratio

lpg will tolerate roughly the same compression ratio as methenol

if you can get a lambda lpg control valve system fuel usage can be cut by upto 25% but normally about 10-15%

lpg tanks have a cut-off valve that won't aloow them to fill to more than 80% so that there is room for the fuel to expand if the tank gets warm

[torxxx]

Right on man. Thank you for the info
I'm going to look into it. Only problems is the winters up here where I live. It gets down to -60 F in the middle of January for about a month. Thinkin the stuff will start freezing uo

[LPGsuperchargedBrumby]

i have no idea how it would run an that temperature or lack of....

hmmmm thinking about it they run alot of lpg cars in like norway and up round there i think, and alot of vehicals in europe run it and some places up in the north of there must get down to close to that temperature so there must be ways to get around it if it causes problems

[RavenTBK]

Only problems is the winters up here where I live. It gets down to -60 F in the middle of January for about a month. Thinkin the stuff will start freezing uo

Propane BOILS (read: returns to gas from liquid) at -44F. I doubt theres a place in the world that gets cold enough to "freeze" propane.

edit: found my info..to fill in the blanks i left before: if the tank/surrounding area falls below -44F, the propane will stay in liquid form and just wont come out of the tank. Wrap it up with a blanket when it gets down to -60F in January.

[RavenTBK]

..and on a side note, I've been seriously considering a propane conversion since LPGSuperchargedBrumby signed up and showed off his ride.

http://www.gotpropane.com does conversions..
Theres also a place I know of in the Tampa FL area that does them as well. When I get the extra money that I can burn, I'm still thinking about going down there and having them come up with a solution. From my initial contacts with them, conversions are cheap.. its just the cost of the tank itself thats high. Either way.. 1.59/gl for propane is a helluva lot better than 2.30/gl for gasoline. :cool:

[Ross]

..and on a side note, I've been seriously considering a propane conversion since LPGSuperchargedBrumby signed up and showed off his ride.

http://www.gotpropane.com does conversions..
Theres also a place I know of in the Tampa FL area that does them as well. When I get the extra money that I can burn, I'm still thinking about going down there and having them come up with a solution. From my initial contacts with them, conversions are cheap.. its just the cost of the tank itself thats high. Either way.. 1.59/gl for propane is a helluva lot better than 2.30/gl for gasoline. :cool:

Over here the gas companies will give you an interest free loan to convert to lpg..... you should check out whether there is a similar scheme over there...

[NorthWet]

Regarding the boiling point of LPG...

It is not quite that simple, as it is going through a phase conversion and you are up against the latent heat of vaporization. IOW, it takes a great deal of energy to convert a small amount of LPG into gaseous propane, and that heat has to come from somewheres. It sucks the heat from the environment, and if there is not enough heat energy available from its environment it will pretty much stay liquid. In general, air is not heat-dense enough to convert much LPG to gaseous form, unless the air is very hot.

Most car applications (at least in the past) have gassifiers that use coolant to supply the heat to change LPG to a gas, but they obviously don't work until the engine has warmed a little.

[LPGsuperchargedBrumby]

Most car applications (at least in the past) have gassifiers that use coolant to supply the heat to change LPG to a gas, but they obviously don't work until the engine has warmed a little.

as long as you have coolant running through your regulator it will work as even cold liquid coolant is warmer than -44f .
i have seen a regulator freeze up due the coolant hoses supplying it being too restrictive (kinked hose) however it was only at high fuel demand that it froze up as there was enough coolant getting through to start and run up to medium rpms sustained high rpms required more heat than the reduced amount of coolant could supply (caused rather alot of head scratching did that little kink)

[s'ko]

Here is some info I got from mergetel.com.

Hello Bosco,

You could use a model 100 mixer (rated for 106 hp) or a model 125 mixer (rated for 126 hp). Either mixer could be used for dual fuel or straight conversions. The difference would be that you would require either a new throttle body or and adapter to mount the mixer to the old carb’s throttle body or you would require an adapter to mount the mixer over the gasoline carburetor for dual fuel. As you are in Los Angeles and the Impco factory is also in Los Angeles, I would probably be uncompetitive with local shops since the parts wouldn’t have to be shipped to Canada and back again. If you can’t find a local installer, I can try to help you but I am not familiar with Subarus and I don’t know off-hand which adapters are required for your engine. Is there any chance that there are similar vehicles already converted to propane in the local junk yards? If there were, that would be your cheapest option by far.



Let me know how you make out.



Frank


I am asking him for a fuel flow diagram and the components that the that the fuel travels through.


Here is a forum that he started for Alternative fuel vehicles.
http://www.mergetel....hpBB2/index.php


BW

[Andyjo]

Here's something for yall'
The guy who invented this, the multi-port gassous fuel injection system, used to live down the street from me, and my dad knows him. He's got a pateint on it an stuff. His name is Wayne Swanson. I was gonna talk to him about doing a conversion, we're going to do it to our old chris craft, with an 8 cyl aluminum block
i didn't really read all the posts, but the whole deal is that propane burns slower, and you get better compression. So you get more powerful and longer powerstrokes. mmmmm... power....

[LPGsuperchargedBrumby]

one thing i havent seen referred to here is the wiring for the safety fuel shutoff valve in the fuel line between the tank and the regulator.
It needs to be wired so it is only open when the ignition coil is firing i.e when the motor is actually running so if you have a crash you don't have lpg floating around

[Ross]

i didn't really read all the posts, but the whole deal is that propane burns slower, and you get better compression. So you get more powerful and longer powerstrokes. mmmmm... power....

More importantly, it has a much higher ignition temperature, meaning you can run much higher compression ratios.

[MilesFox]

9.5 spfi compression turbo motors. i was told the reason diesels had turbos or multiple tubos or 3 lbs boost is more for economy and emissions more so than for power

[LPGsuperchargedBrumby]

9.5 spfi compression turbo motors. i was told the reason diesels had turbos or multiple tubos or 3 lbs boost is more for economy and emissions more so than for power

try taking the turbo off any diesel and see what happens......it loses power and blows black smoke , to run a turbo diesel without a turbo you haveto cut the diesel pump back to stop it wasting fuel

more boost=more air
more air=more fuel can be burnt
more fuel=more power

more power means less throttle needs to be use... saving fuel
the reduced extra fuel use returns you to the same fuel consumption per hp (roughly) as a N/A motor while leaving the extra power in reserve

[WoodsWagon]

Try running a N/A diesel at 7k feet. loses lots of power. Turbo's do a lot for power in diesels. Blowing black smoke is just wasted fuel.

[NorthWet]

Propane does have a higher ignition temperature than gasoline, but that in and of itself has no real bearing on detonation. And with flame propogation speed ("slow-/fast-burning"), it is better to have faster-burning. (The slow-burning "high-octane" gas requires more ignition lead in order to optimize where in the power stroke maximum combustion pressure is reached, all the time wasting energy as it burns prior to TDC.)

Gasoline is just chock full of not-terribly stable complex carbon bonds (pentane, hexane, heptane, octane) that tend to decompose in the heat and pressure of the endgas, producing molecules that have a lower flash point than the original molecules. If the flash point gets low enough and the endgas temperature gets high enough, spontaneous ignition of the endgas occurs (aka detonation).

Propane's advantage regarding detonation resistance is that it does not have complex carbon bonds that can decompose in the endgas after primary ignition has occured. Methane, an even simpler hydrocarbon, has an even higher resistance to endgas detonation (equiv of 120 octane, IIRC).

Another advantage to propane is that it has a wider burnable air/fuel-mixture range than does gasoline.

Regarding diesels, supercharging allows the engine to be smaller/lighter for a given power output than an NA engine. And diesels operate on "detonation" (well, spontaneous ignition of fuel/air). Their fuel is given a cetane rating rather than an octane rating. The higher the pressure/temperature at the time of injection the better, and the higher the thermal efficiency. Diesels are set to blow black smoke in an attempt to get the most power; it is an attempt to burn every possible oxygen molecule in the cylinder. Supercharging allows much more oxygen to be available to burn, so the engine need not be set to run overrich at max power, improving specific fuel consumption and emissions.