Propane injection in Diesel Pusher?

[Muledeer2]

Has anyone tried propane injection on their diesel older diesel pusher, I have a 36ft. motorhome 24,000 GVW with a 250 hp, 3208t Cat engine and was thinking of trying propane injection, the setup is easy for me and I already have a 65 gallon propane tank on the motorhome. I have heard it improves fuel mileage and power with just a small amount of propane injected at the air inlet to the turbo...........
Any Thoughts please
Muledeer2

[halfwright]

Since I had never heard of doing this, I ran a search on it. And, I am still undecided. There might be some truth to the advertising, but a whole lot of it looked like the old "50 MPG carburetor" story. It would seem to me that the energy required to move something down the road would be the same, whether it came from propane, diesel or gasoline. I guess the only way to be sure would be to try it. And, the payback on a $800 system is too slow for me.

[Muledeer2]

I think the propane is a catylast for the diesel fuel, it makes it burn at 95% instead of 75% effiency and also cools down the inlet air. Might be junk science but quite a few companys provide systems including advanced Turbo and even banks. I was more worried about engine temps because you have to make more heat to get more power, unless the cooling effects of propane offset the heat gain. There are people who have built their own for a couple of hundred bucks and it's not hard to do. Just looking for ideas.........and Thanks for the Feedback Muledeer2

[Muledeer2]

We now have cars that get 50 MPG, but they don't have carbs LOL, hoping to do more research and I will post my findings, I think I might build my own system, it's just a propane regulator (adjustable) a small 12 volt solenoid, a long hose to the air inlet, and a switch on the dashboard to turn it off and on with an indicator light, My first thought is to try it out on a long hill, that is a 2nd gear hill for me everytime I go out I have to climp it.
As for increase in mileage We shall see about that too.

A big Thank You for checking it out
Muledeer2

[BFlinn181]

What transmission do you have and how much torque can it handle? In addition, i'd think you need to install a pyrometer to monitor EGT now and get a baseline for temps before you add propane injection. I also question your manual control of your LP solenoid. If you forget and leave it on when engine shuts down you will fill the intake with enough LP to create a very effective bomb. Be sure to include an ignition controlled shut off in the circuit. Not sure getting up a hill a little faster is worth the danger.

[stumpnc]

You will notice a substantial performance increase injecting propane.
Propane has a higher flash point than diesel, so the diesel fuel ignites first and then that ignites the propane that is mixed with the intake air charge. The propane stabilizes the burn in the combustion chamber allowing more of the injected diesel to burn completely. The systems inject vapor into the intake air duct just before the turbo. Usually a solenoid valve is used and that is activated by a adjustable pressure switch that reads turbo boost pressure. It is done this way so no propane can be injected until boost pressure is up. some people have it come on above say 10lbs boost some at a lower setting so it will trickle in and enhance fuel economy. A toggle switch on the dash turns it on and off. Usually you would use a vacume sensing liquid LP service regulator. These type of regulators are fed liquid propane and have hot coolant water circulating through them the liquid is vaporized in the regulator and it will not open until it senses manifold vacume. Kind of a safety safety. It prevents any chance of any liquid entering the intake air system until it is a vapor. Which could be a potential issue in severe cold weather. You could supply vapor off the RV LP tank after the pressure regulator I believe it is like 10 inch wc pressure it will work that way.Performance will increase milage will increase. etc. But,
Yeah there is always a BUT in there, you will not save any money it will cost you a little more per mile to run because of propane costs. It does work it is safe ,There is a lot of info on the web if you google it. I have a setup I put together for my semi truck but never have gotten around to putting it on.

[stuhly]

A neighbor had a unit called a propane topper on a non turboed AC 190 tractor. It smoked like it was on fire until he turned on the propane. Smoke would clear up and he could pull one gear higher.

[halfwright]

Originally Posted by stumpnc

You will notice a substantial performance increase injecting propane.
Propane has a higher flash point than diesel, so the diesel fuel ignites first and then that ignites the propane that is mixed with the intake air charge. .

I think that is bass ackwards. I can light propane with a cigarette lighter easily and I can put out the same lighter with diesel.

[stumpnc]

Originally Posted by halfwright

I think that is bass ackwards. I can light propane with a cigarette lighter easily and I can put out the same lighter with diesel.

Let ,me rephrase that the auto ignition temp is higher on LP than diesel that is why it lights after the diesel does in a compressed environment.

Fuels and Chemicals - Autoignition Temperatures
The Autoignition Temperature - or the minimum temperature required to ignite a gas or vapor in air without a spark or flame being present - are indicated for some common fuels below:
Fuel or ChemicalAutoignition Temperature(oC)(oF)Acetaldehyde175347Acetone465869Acetylene305581Anth racite - glow point6001112Benzene5601040Bituminous coal - glow point454850Butane405761Carbon7001292Carbon bisulfide149300Carbon disulfide90194Carbon monoxide6091128Charcoal349660Coal-tar oil5801076Coke7001292Cyclohexane245473Diethyl ether160320Diesel, Jet A-1210410Ethane515959Ethylene490914Ethyl Alcohol, Ethanol365689Fuel Oil No.1210410Fuel Oil No.2256494Fuel Oil No.4262505Heavy hydrocarbons7501382Hydrogen500932Gas oil336637Gasoline, Petrol280536Gun Cotton221430Kerosene295563Isobutane462864Isobutene 465869Isooctane447837Isopentane420788Isopropyl Alcohol399750Light gas6001112Light hydrocarbons6501202Lignite - glow point526979Magnesium473883Methane (Natural Gas)5801076Methanol Methyl Alcohol470878Naphtha225437Neoheaxane425797Neopenta ne450842Nitro-glycerine254490n-Butane405761n-Heptane215419n-Hexane225437n-Octane220428n-Pentane260500n-Pentene298569Oak Wood - dry482900Paper450761Peat227440Petroleum400752Pine Wood - dry427800Phosphorus, amorphous260500Phosphorus, transparent49120Phosphorus, white3493Production gas7501382Propane470878Propylene458856p-Xylene530986Rifle Powder288550Triethylborane-20-4Toluene535995Semi anthracite coal400752Semi bituminous coal - glow point527980Silane< 21< 70Styrene490914Sulphur243470Wood300572Xylene