428 Lp
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Joined: Jul 2002
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From: Long Island USA
Funny thing, when mentioning how much energy a certain fuel contains.
Anyone want to venture a guess as to how efficient an internal combustion engine is?
Sure, there's more energy in gasoline - but we're losing 80% of it out the exhaust.
I wonder, how much propane comes out the exhaust ?
Like hetz said, higher compression, higher efficiency - I THINK.
Overall, you might get as much energy out of the ENGINE using gas or propane, or other various touchy-subject fuels
depending on compression, cam timing, etc.
Why? because the efficiency of burning gasoline (which has to be atomized) vs. propane which is just allowed to evaporate before ingestion, meaning each individual molecule mixes with air - with gasoline, the injector can only atomize down to a certain size. And it's not at the molecular level, that's for sure ...
Anyone want to venture a guess as to how efficient an internal combustion engine is?
Sure, there's more energy in gasoline - but we're losing 80% of it out the exhaust.
I wonder, how much propane comes out the exhaust ?
Like hetz said, higher compression, higher efficiency - I THINK.
Overall, you might get as much energy out of the ENGINE using gas or propane, or other various touchy-subject fuels
depending on compression, cam timing, etc.Why? because the efficiency of burning gasoline (which has to be atomized) vs. propane which is just allowed to evaporate before ingestion, meaning each individual molecule mixes with air - with gasoline, the injector can only atomize down to a certain size. And it's not at the molecular level, that's for sure ...
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From: Klamath Falls OR
Originally Posted by the_hetz
That was my original thought, that LP would have higher compression....
It seems that LP has lower energy than gas, and since it can handle the higher compression (better efficiency), that is how it's compensated for not having as much energy. Makes sense to me. Although I'm fairly certain that higher compression isn't REQUIRED, which is why I was wondering if there was a simple generalization about these LP heads being higher comp ratio.
It seems that LP has lower energy than gas, and since it can handle the higher compression (better efficiency), that is how it's compensated for not having as much energy. Makes sense to me. Although I'm fairly certain that higher compression isn't REQUIRED, which is why I was wondering if there was a simple generalization about these LP heads being higher comp ratio.
I'm sure if LP was more efficient then gas, then more people would run LP over gas. Also you have to add those BIG heavy tanks to the car/truck. That doesn't help things........JMHO
Needsmorecoffee.
Joined: Oct 2004
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From: CT
Originally Posted by Ford428CJ
Sorry but C8AE-H heads was used on LP and Gas engines.
Elder User
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From: Klamath Falls OR
Originally Posted by FFR428
Are you sure on that Wes? I remember Ray Hillenbrant selling those propane industrial 428's and he said they came with FT heads and intakes on them. That's why he never offered complete engines just shortblocks. He would include the heads if you wanted them tho. But the shortblocks were std issue CJ. HD blocks, IUB cranks, big bolt C7 rods and cast CJ pistons.
I dont have the car now but my Uncle has the intake and the LP stuff went elsewhere. I'll dig up some pics of it.
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From: Klamath Falls OR
That 428 turned into a solid roller motor that went into my 76 F-150 4X4 that I have the pics of. Truck is gone now but I kept the 428 LOL
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Brett Foote
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From: Long Island USA
Originally Posted by Ford428CJ
As far as efficiency goes, Gas is more BTU's of heat then LP. Witch it would make it more efficient.
If gas has more energy, but is used less efficiently, the sum total is the same. Or worse.
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From: Klamath Falls OR
Originally Posted by krewat
Plenty of things effect efficiency... Like I said, atomizing gasoline is less efficient overall than vaporizing propane.
If gas has more energy, but is used less efficiently, the sum total is the same. Or worse.
If gas has more energy, but is used less efficiently, the sum total is the same. Or worse.
When you are talking BTU's of heat.....That never changes!!!! And going from carb to EFI is only 2 to 3mpg Tops in difference. Or better yet check out Ski Doo and there New Direct Inject 600cc 2 stroke for efficient. And gas going through a carb is still more efficient then LP or more people would have done LP to begin with. And now Manufacturers are going to Direct Injected Gas, LP doesn't stand a chance.
So, you can build an LP and spend the same amount to buy it, like pump gas! But you will pay a little more for that LP because of the lose of heat (BTU's) compared to Gas. I'm not saying dont build one to run on LP but if you are trying to do it to improve your mileage.......Better Look at a Diesel conversion then!
If you are going to build an LP rig, plan on using cast iron rings and make some other changes. That will help the life of an LP engine and put some ridiculas hours on it. JMHO
Elder User
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From: Klamath Falls OR
Here is a cool link for ya!!!! They do sound cool. Ski Doo ROCKS!!!!!
http://www.ski-doo.com/brphtml/skido...h/en/Index.htm
http://www.ski-doo.com/brphtml/skido...h/en/Index.htm
FTE Leadership Emeritus
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From: Long Island USA
Originally Posted by Ford428CJ
When you are talking BTU's of heat.....That never changes!!!!
Internal combustion engines are about 20% efficient overall, about 25-35% thermal efficiency.
The gaseous nature of propane allows a more complete burn, raising the thermal efficiency.
Anyway...
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From: Klamath Falls OR
Originally Posted by krewat
Of course not, but harnessing and actually using that energy, that's something completely different.
Internal combustion engines are about 20% efficient overall, about 25-35% thermal efficiency.
The gaseous nature of propane allows a more complete burn, raising the thermal efficiency.
Anyway...
Internal combustion engines are about 20% efficient overall, about 25-35% thermal efficiency.
The gaseous nature of propane allows a more complete burn, raising the thermal efficiency.
Anyway...
Hotshot
Joined: May 2003
Posts: 11,141
Likes: 25
From: south louisiana
Every LP conversion I've ever seen got fewer MPG's than gasoline. That in itself should tell you something. If LP were more efficient, you'd see them on the road. LP burns cleaner, but it's not more efficient.