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Old 02-23-2006, 10:45 PM   #1
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Propane injection ,extra horse power on a hill ?

This is my first posting wanting to know if adding propane injection to the intake manifold on a International DT360 is possible ? have seen a kit for a Ford power stroke engine from Bully Dog on tv .
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Old 02-24-2006, 08:17 AM   #2
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I looked at this a while back. I can't figure out the advantage (except for cleaner burning). They claim more power, which would be an advantage if true, but I'm not sure it's a real gain.

What I reviewed led me to believe that the injection adds about 20% propane to the combustion mix. They claim 20-25% better mileage. Well, if you add 20% more fuel, you get a 20% increase in mileage. If you add 20% more fuel, you also get some amount of increase in power.

I couldn't figure out how you could come out cheaper burning more fuel.

I may be misunderstanding the concept some, though.
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Old 03-22-2006, 10:53 AM   #3
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I saw a show on tv (horsepower TV or something like that, I think it's on Spike TV on sundays) that was trying to get a diesel silverado to do under 15 seconds in the 1/4 mile. I think they dynoed before and after the bully dog propane system that they put on , and it gave significant HP increases (like maybe 100?,) as well as a small torque increase. They said that it is an approximate equivalent to nitrous in a gasoline combustion engine.

However, I found this on the internet when I googled this subject....


I want a skoolie, but I'm kinda broke right now. It will be mine, oh yes, it will be mine.
(I want air brakes and good fuel economy... like 7-8MPG)
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Old 03-22-2006, 12:22 PM   #4
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Propane for more power diesels only

Adding propane to a diesel is like adding nitros oxide to a gas engine. The propane chemically reacts with the diesel and makes up to 50% more power. The propane is only added at full throttle for moving up the big hill with a heavy load. Propane is added in very small amounts and a 7 gallon barbeque bottle will last a month. The MPG is not drastically affected. This gas really makes Ford powerstroke diesel "come alive". I've been thinking of adding a propane system to my Crown bus with a Cummins. There is no substitution for cubic inches and raw power. Some times the propane could save downshifting on a hill. The engine does burn cleaner and not smoke quite so much with full open throttle. If the diesel has a turbo, the engine and exhaust temps must be monitored. I have saved an article for a system for about $400 and Bully Dog will sell a complete kit for $2000. The miles and age of a diesel does not seem to be of importance. Frank
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Old 03-22-2006, 12:44 PM   #5
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Do it to yourself Adding propane

Propane Article with setup instructions and Pics..."

I first heard about the addition of propane to a diesel engine from some of the threads on the ford diesel website. The concept is that diesel fuel when it burns, doesn't burn completeley. In fact it only burns about 75%, so the total available power(in the form of released btu's) from a given amount of fuel is somewhat wasted, especially in a non-turbo deisel engine. The addition of propane(lpg) to the intake air, acts as a catalyst, and allows the diesel fuel to burn more completely releasing all the available power. The result is a cleaner burning engine(less soot, cleaner oil) and increased power for any given volume of fuel, and therefore, increased fuel economy.

I was intrigued, so I checked into it. There are a few companys that offer after-market bolt on systems, most of them in and around the $500 U.S. price range, but most of those are designed for trucks which are running a turbo on the engine. Since I don't have a turbo on mine, and don't really want to add one to my tired, old engine, I was hoping to find a system that would work on a non turbo application. A company named Bully Dog Technologies did e-mail me back and said their system would work on a non turbo application, but it was still $600 U.S.(about $900 Can.) and I figured I could build something that might work for cheaper than that. One guy described a system he made at home, and although his was also a turbo application, I thought it could work. So I built much the same system.

I would like to put a word of warning here! Propane can be very dangerous if not used properly. If respected, however can be very safe. Always check all fittings for leaks using soapy water prior to running the system. You can never be TOO careful!

My plan was to have the lpg setup so as to come on when maximum power was needed but not run all the time so as to conserve on the added cost of the purchase of lpg.

Equipment required...

Vapour-type propane tank(BBQ style 20lb'er works fine)
High to low Pressure regulator(Acetylene one works great)
Hobbs pressure switch
Electric solenoid Lock-off switch
Micro switch for throttle activation
Various hose & fittings
Dash mounted toggle on/off switch

My total cost for all this stuff was less than $250 Can. but I did scrounge some of it second hand, so to purchase it all brand new would probably run closer to $300 Can.


A long (10ft.) extension hose connects the tank sitting in the back of the truck to the Acetylene regulator mounted at the front of the box on the driver's side. I had to wire wrap the hose fittings to connect the high pressure hose to the regulator.(Don't want any leaks here!)

click here for tank pic

Next, I mounted the acetelyene regulator and the electric Lock-off valve in a box that was accesible, but safe from things bouncing around in the bed of the truck. I put the lock-off on the low pressure side of the regulator so that if it somehow didn't completely close off the flow, the leak would at least be a low pressure one. It has been suggested that maybe a second lock-off valve connected to a separate on/off toggle on the dash might be a good idea, to have absolute control. I can't see anything wrong with that idea. I have the regulator set to around 4psi pressure. This is the pressure in the line. When the flow is activated, the low side of the gauge drops to less than 1psi.

Click here for pic of regulator

I then ran 1/4" fuel rated hose from the Lock-off valve through a solid brass fitting mounted at the forward drivers side corner of the box down along the inside of the frame rail and up over the top of the engine along the firewall to the air intake hat. To connect to the intake I used the same type brass 3/16ID. fittings with 0-ring seals and a small 4" length of copper tube on the inside with some 8 holes drilled through one side to allow the propane to disperse into the incoming air stream.

Click here for pic of intake

The electrical connections consist of running a wire from battery power through a micro switch mounted alongside of the fuel injector pump, just barely coming into contact with the timing advance lever. As the throttle is opened, the advance lever moves out/away from the pump, and eventually when the throttle is at about the half way point, the micro switch is depressed and allows current to flow.

Click here for pic of micro switch

I then ran the electrical through a Hobb's style pressure switch connected inline with the oil pressure gallery. This switch is normally "open", and only allows current to flow when the oil pressure is above 15psi. The other one on the left in the photo is for my "idiot" light on the dash which is not related to the lpg setup, but is normally "closed" and only lights up if oil pressure drops below 15 psi!! (paranoia factor)

Click here for pic of Hobbs switch

Finally, the wiring runs through a toggle switch on the dash(the little blue one down low)which is also connected to the little green led up on the steering column to show when electricity is flowing, and thus indicate when the lpg is also being activated. From there the current runs to the Lock-off valve in the truck box mounted alongside the regulator.

Click here for pic of Dash switch

Well, that's it!

Does it work you might ask? You Bet! It took a bit of fiddling to get the micro switch set where I wanted it to be, and some fiddling to find the right amount of pressure to run the system at, but once I got it right, there was no turning back. The difference in power is immediate and impressive. It doesn't "snap" on, but kind of comes on smooth and strong. I think because the distance from the regulator to the intake is some 11 ft, there is about 1 second delay, but barely noticeable. I did a few tests to get some numbers. On the flat, shifting through all 4 as fast as I could, 0-60mph, without the lpg on, I could do it in about 22 seconds(3 tries averaged) When I turned the lpg on and did the same test, I spun out in 1st, but still made it to 60 in about 16 secs. Climbing a local hill, about 5% grade I had about 2,000lbs of gravel in the back, and without lpg, I couldn't hold 55mph in 4th, and had to shift down after about 1/2 mi. When I did the same thing with the lpg on, I had to back off the throttle at about 3/4 mi, because I was gettin' up to 65mph!!(speed limit 55)

So, for anyone who is looking for a way to get more power, at a reasonable cost, with some nice side benefits, without the added stress to an engine of a turbo, then lpg is a great way to accomplish this. Go for it!

I will mention again, this stuff is great if used properly and respected, but we know that propane can do some serious damage to life and limb if abused. Double check your system for leaks before using it, and better yet, have it inspected!

Happy Truckin'!.....Don

I thought I'd add a little update paragraph to this article.

It's been a few months now since I first had the lpg up and working on my truck. I have not been able to notice any increase in fuel economy, in fact, my fuel mileage has gone down significantly, and I know why. It's because I can't seem to be able to get my foot off the "go pedal" It's so hard with all that power!!

Actually I wanted to mention a couple things. One is that I finally had to fill the same 20lb'er that I started with, but that's after about 8-10 tanks of fuel run through. So, to me, for 15 bucks to fill the lpg tank, it's well worth it. Next though, I've had to change the setup somewhat. I'm finding that the single stage "acetylene" regulator that I use is a little difficult to control. I seem to be always adjusting it, to find the "sweet spot". I'm convinced that it is because of changes in pressure in the tank due to ambient temperature variations. So, I've put a second small regulator in the low pressure line nearer to the engine. This allows me to drop the tank pressure to between 10-15psi with the 1st stage, and then the second stage I am now running at about 5/6psi through a 5/32(instead of the original 3/16)inch orifice to the engine. As the tank pressure goes up and down slightly, the pressure at the engine remains more/less constant. One guy e-mailed me to say he had done much the same thing, but using a Sears craftsman model 359H 2stage regulator(from a welding rig) on his, but I couldn't find such a regulator here in Canada.
here is a pic of it

I also have found that if the micro switch is set to allow flow of lpg at very heavy throttle applications, it seems to smoke black a lot. Lots of power, but I found that if I set the switch so that the lpg flows at a throttle postion just over that required to lightly accelerate on the hwy from 60mph, then the lpg flows sooner, with lesser throttle application, but there doesn't appear to be the black smoke(overfuel), until I really get into the full throttle position, which is now often not needed except on the larger hills.

I also found that if the lpg hasn't been on for a long time, then the first time or two that it is turned on, there is often a lot of black smoke for a bit. I am not really sure what this is about, but it seems to clear up very quickly, and I am guessing that it is somehow built up carbon/soot deposits being "blown" out of the engine when the lpg is being used. Once lpg has been on for a few seconds, it clears up, and then there is hardly any smoke out the exhaust at all, even with fairly heavy acceleration.

Overall, I still feel that this is the single most significant thing I have done to my N/A engine with respect to getting more power without having to spend the big bucks, and have the added stress of a turbo.

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Old 03-22-2006, 12:47 PM   #6
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Old 03-22-2006, 02:43 PM   #7
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Excellent article! After you explained it, I think that this is something I would like to do in the future (after I complete the veggie fuel conversion). Very cool. Thanks for posting this great information.
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Old 07-20-2006, 01:03 AM   #8
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Nifty how much does a system like this cost?

drivin up mountins at 20mph sucks
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