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Topic: Propane/Diesel Combo (Read 931 times) previous topic - next topic
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Propane/Diesel Combo

Yahoo Message Number: 4100
A Post from the Diesel-Rv's forum.. How would the engine manufactiures honor warranty on this type of fuel consumption?? Bob,

Arron Gold asked me to respond to this since I have been using propane injection in my Cummins engine for a couple of years now.
There are two companies that make the kits for the propane engines and their biggest customers are the diesel pickup owners. There are some big rigs that are using it also. The two companies are Bully Dog and ATS.
Propane has been used in diesels since the twenties when farmers used it to get extra power from their tractors. An old head at the Cummins factory tells me that truckers have been using it in the Canadian Rockies for years. It is just coming around again.
The theory behind this is that the propane acts as a catalyst. (Both companies tell the same story so it must have some veracity.) What they tell me is that a modern diesel engine burns about 75 - 78% of the fuel that is injected into the cylinders. By fumigating the intake air with propane, so it is completely mixed, it increases the diesel burn to about 95%. This more efficient burn translates to extra power for climbing or to extra mileage.

I use the propane only for hill climbing and occasionally for acceleration since I have only a 7 1/2 gallon bottle for the engine. I have a converted GM bus with a Cummins 903 engine and before propane, I could maintain a maximum of 37 mph going up a 6% grade. That is towing an El Camino for a total Combined Gross Weight of 33,000 lb. With the propane, we usually maintain right at 50 mph with the same combination.
A couple of reports from truckers that i know that use propane: One had his truck dynoed before and after. He had a 315 Cat engine. He saw an increase of 70 hp and 236 lb./ft. of torque. He reports that he is now able to maintain the 55 mph speed limit going up the Grapevine fully loaded.

Another trucker that runs from the central California valley to Ohio and return, with both he and his wife team driving, use the propane all the time. They report that mileage went from 6.2 to 6.8 mpg, approximately a 10% increase. His wife loves it because of less shifting in the mountains. Plus they were able to cut a whole hour off their trip time.
I wish I had that 55 gallon tank you have - I have no room to give up - then I would run it all the time. When talking to the gent at Cummins, he brought up the fact that it would decrease the engine life somewhat.
Anytime you increase the power output of any engine by any means, you will decrease its life. The top of the head figure he gave me was that it might decrease the life by as much as 25,000 miles, which out of a 500,000 mile or greater engine is not that much, especially for the extra boost you get when needed.