Propane power/torque vs gasoline

[Terry Metro Lawn]

This is from Roush CleanTech:

[rlitman]

I'm shocked that the two are so close together. Propane carries such a lower energy density that generators running on propane are derated something like 10% in power output.

[djagusch]

Up compression, change timing, and dump enough fuel is all that is needed to get them close.
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[Terry Metro Lawn]

Originally Posted by djagusch

Up compression, change timing, and dump enough fuel is all that is needed to get them close.
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Actually, DJ, these are factory vehicles. I don't think they change anything internally. They just flash the PCM. That's why the warranty is intact.

As far as dumping more fuel in, I haven't noticed that much difference.

Jack Roush does a good job with these. It seems, at least, FoMoCo thinks so!

[djagusch]

Terry,

Fact propane has less energy than gas by approximately 20%. Do you disagree?

If it has less energy you need to use more to produce the same amount of power. Do you disagree?

If you agree with the above they must dump more fuel than gasoline to produce the same amount of power.

PCM flash can change fuel amounts and timing. Do you disagree?

If Roush has not increased the compression ratio he has not taken full advantage of the fuel. Do you disagree? In some circles not using it that way isn't the most green.
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[Terry Metro Lawn]

Originally Posted by djagusch

Terry,

Fact propane has less energy than gas by approximately 20%. Do you disagree?

If it has less energy you need to use more to produce the same amount of power. Do you disagree?

If you agree with the above they must dump more fuel than gasoline to produce the same amount of power.

PCM flash can change fuel amounts and timing. Do you disagree?

If Roush has not increased the compression ratio he has not taken full advantage of the fuel. Do you disagree? In some circles not using it that way isn't the most green.
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Here's what I find at www.roushcleantech.com:

Roush Propane Vehicles:

Have a 5 year 60,000 mile warranty

Have Identical Performance

Produce 24% less CO

All while reducing fuel costs by 40%


Personally I have neither the knowledge nor the equipment to make these statements. I do, however, trust those who have made their living for the past 40 years making vehicles go very fast when they say it.

I'm not enough of an expert to argue with Jack Roush. ;-)

[djagusch]

I thought you are the expert of the forum. I would expect you to know the basic properties of propane. Thanks for answering the questions.
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[Terry Metro Lawn]

Originally Posted by djagusch

I thought you are the expert of the forum. I would expect you to know the basic properties of propane. Thanks for answering the questions.
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To which questions do you refer? Are there fewer BTUs per gallon of propane than gasoline? Yes. Depending on the grade of gasoline 7-25%. What I DON'T know is how efficient gasoline is being used in late model Ford Trucks.

I assume Roush knows what they are talking about. They are the ones partnering with Ford.

I am quite familiar with the basic and complex properties of propane. It is the third most used engine fuel in the world and I have used it with great success for the past 35 years. I've proved it's capabilities in both practical application and on the dyno.

Roush has tested them exhaustively both in racing and dynomometer tests showing there is no perceptible difference in the performance of both fuels.

I don't know how much plainer I can make it. If you have information to the contrary please make it available. I can only speak from experience.

Perhaps this will help:

http://www.youtube.com/watch?v=N6ZKpGIgWZ4

[Terry Metro Lawn]

As far as the "expert" part, I don't know about that. I think I've just outlived those better equipped! ;-)

[djagusch]

Assume many things.
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