Propane injection revisited

[vetman]

With diesel topping $3.00/gal in many areas, is there some advantage for supplementing with propane? Propane is running about $1.89/gal in my area. I guess I don't know about the BTU value comparison or any other considerations that may be involved, but thought if it were possible to use 1/3 less diesel and supplement with propane that might keep cost under control. Is there a way to run propane as a supplemental fuel instead of just a performance enhancer?

[DmaxMaverick]

Excellent argument.

Performance vs. supplemental??? Well....that all depends on how you use it. If you drive the same after, as before, adding propane should decrease your fuel costs considerably....As long as the cost vs. BTU offset remains spread.

[Mark Rinker]

I have about 8,000 towing miles on since installing the MSD Digitial Propane Injection system, and yes it can be run as a 'replacement fuel' as well as a 'supplemental fuel/power enhancer'. Even at the same time, with a little thought as to when and how much to use it.

Overall, I am very happy, but there are pros and cons, and the whole picture is VERY dynamic to fuel ratios, engine loading, optimal boost, relative fuel costs, etc. You are 100% on track...if you can source propane readily at 65% of the cost of #2 diesel or less, then and only then does it makes sense, if your goal is economy. (If your goal is cheap, simple power adder, its all good IMHO.)

If you tow heavy, and fumigate at about 4:1 diesel to propane while towing, you get more power for about the same overall fuel consumption (in gallons) as #2 alone, and will save the difference in the relative cost of #2 vs. propane.

The MSD system has a PC software interface that allows you to change the propane rate from the default of 100 (max power) to as low as 1, or 1% of that value. I have found that '5' setting yields a 4:1 diesel to propane average. Using the 100% map setting will give buku power, but burn lots of excess fuel, at about 2:1 diesel to propane!

Since the propane displaces an equal amount of air from the intake, too much propane is wasteful as there is not enough oxygen available to burn it completely. Also, I have found that driving empty or even with unloaded trailer consumes more total fuel when fumigating with propane. I now only run propane when towing AND loaded, switching it off for the empty trailer deadheads home.

If you don't need the extra power, (i.e. don't tow regularly) I would look for ways to make it more fuel efficient first, i.e. exhaust, intake, JK's towing ECM programs, etc. Propane will stack nicely on top of all these basic mods, if you desire MORE POWER later.

In short, supply of cheap propane + the heavier you tow = the happier you will be with propane.

I have to admit, I drive faster and get more miles on every day after adding propane, so my results might be better if I could get the 'perma-grin' off my face, and quit spanking Powerjokes and Cummins all day long up steep grades.... :)

[ronniejoe]

...if I could get the 'perma-grin' off my face, and quit spanking Powerjokes and Cummins all day long up steep grades.... :)

Never let up!:D

[vetman]

Thanks for the info... This is something I am seriously considering. Right now I'm running an Edge Hot Juice Level 3 most of the time, and level 1 while towing. I've done the intake switch, but not the exhaust...yet. I feel I have plenty of power when I need it , but really want the economy and cost savings on fuel. Of course, the time I need it most is when towing my travel trailer. So, do you recommend the MSD propane injection, or should I look at others too? Keep in mind that besides the fuel savings, I can also get an "alternate fuel" tax credit in my state (WV). Seems like a no-brainer! How hard is propane injection to install? I'm a backyard mechanic with 20 yrs experience....

[Mark Rinker]

My strong opinion is that the MSD Digital Propane Injection system makes all others look like BBQ grill parts.

Since it has its own ECU it can use a variable fuel map and pulse width modulation to control propane flow. It monitors critical engine parameters (RPM, boost, throttle position) and gives the user control over when and how much propane to flow - and better yet - when to STOP with user defined RPM and boost limits.

It makes over fumigating nearly impossible, unless you bypassed the software safeguards and/or modified the factory fuel map.

Installation can be done by anyone handy with tools and the desire in under 10 hours, faster if you are good. Mostly mounting tank and running lines - a little tapping of electrical connections. Very well engineered package.

All other systems are mechanical in nature and the best simply use boost pressure to regulate propane flow. Thats about as smart as they get. After what I have learned with the MSD controls in place, I am suprised that anyone running a mechanical system and adjusting flow with a set screw and screwdriver doesn't burn down their engine in short order.

MSD lets the user go to the (power) wall first, enjoy the ride, then back off and save some money while making BIG power numbers.