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Spartan Locker Promo Running now @ ROCKRIDGE 4WD plus FREEG2 Disc Brake Conversion Kit for Jeep Wrangler YJ TJ LJ ChTJ Wrangler 4" Rough Country Suspension Lift Kits in

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Unread 09-21-2013, 10:42 PM   #16
dnuccio
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Quote:
Originally Posted by zj97ltd View Post
I worked at Home Depot for 7 years. I've seen a couple get jacked up pretty bad lol.
my comment stands.

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Unread 09-22-2013, 10:21 AM   #17
stovie
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Ok I put a video of my jeep running off propane on YouTube here's the link

http://youtu.be/-PTWmiVWw0k
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Unread 09-22-2013, 11:06 AM   #18
sebian
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I know that folks in the UK and other places in Europe have the LP conversion kits. Not sure where the OP is from, but it might be worth looking into the kits that our Euro friends are using, and try to duplicate that.
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Unread 09-22-2013, 03:01 PM   #19
abraham743
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And 10:1 compression implies that if your cylinder volume was 40 cubic inches it would be compressed to 4 cubic inches. The tighter you squeeze your air fuel mixture the less stable it becomes and more easily ignites. The 14.5:1 you referred to is air to fuel ratio. Compression ratio and a/forums ratio are determined independently of each other. If you want to run lp check out gotpropane.com
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Unread 09-22-2013, 05:08 PM   #20
Maine1994ZJ
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Quote:
Originally Posted by dnuccio View Post
it takes a special kind of stupid to total a forklift
I worked with a guy who totaled a 3 day old Daewoo G25S when he turned 90* off the downhill side of the loading ramp.
He bailed off when it started to go, and it's a good thing.
It rolled 6 times before crashing into the road at the bottom of the hill 50 feet below.


Yes, that IS a special kind of stupid....
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Unread 09-22-2013, 06:29 PM   #21
Rich93ZJ
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So it looks like in the video you are running WOT for it to idle. I dont think you will get very far in that condition.
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Unread 09-23-2013, 02:30 AM   #22
stovie
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Quote:
Originally Posted by abraham743
And 10:1 compression implies that if your cylinder volume was 40 cubic inches it would be compressed to 4 cubic inches. The tighter you squeeze your air fuel mixture the less stable it becomes and more easily ignites. The 14.5:1 you referred to is air to fuel ratio. Compression ratio and a/forums ratio are determined independently of each other. If you want to run lp check out gotpropane.com
Sorry I meant air/fuel instead of cr, I fixed it so there shouldn't be anymore confusion there(I hope!)

Yes the jeep is running wide open throttle! It's suppose to be like that in my experiment! I'm seeing what fuel economy and power I get with the air always being at full charge and the fuel being the only thing that's variable like a diesel. Like I said before I believe that the engines we have now are running way to rich!! I believe the air/fuel ratio of a car should be something more along the lines of 145-1 not 14.5-1!! Or basically cr*14.5=proper air/fuel ratio !
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Unread 09-23-2013, 04:53 AM   #23
james_2k
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i have lpg in my 4.0 wj and it runs fine.

the install cost 2000 though so it is a bit more involved than what this setup looks like! ( plus its a 90 ltr tank in the rear)

lasts around 300 miles with normal driving. (LPG/Propane for driving purposes is around 0.70 per litre as opposed to petrol ~ 1.4/l)
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Unread 09-23-2013, 08:25 AM   #24
zjosh93
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Quote:
Originally Posted by stovie View Post
Sorry I meant air/fuel instead of cr, I fixed it so there shouldn't be anymore confusion there(I hope!)

Yes the jeep is running wide open throttle! It's suppose to be like that in my experiment! I'm seeing what fuel economy and power I get with the air always being at full charge and the fuel being the only thing that's variable like a diesel. Like I said before I believe that the engines we have now are running way to rich!! I believe the air/fuel ratio of a car should be something more along the lines of 145-1 not 14.5-1!! Or basically cr*14.5=proper air/fuel ratio !
The stoichiometric air fuel ratio for gasoline is about 14.7:1. That's the point at which there is just enough oxygen in the mix to combine with all the carbon and hydrogen atoms (in a simplified model) in gasoline. If you more air than that you have extra oxygen sitting around doing nothing and your power drops off, oxides of nitrogen increase, and you start getting lean misfires. Plenty of people including the OEMs tried running super lean engines (Lean Burn) in the late 70s and early 80s because of the gasoline crisis but nothing good ever came of it.

The power to turn the engine comes from the reaction of air and fuel. Because of this you can think of power in terms of fuel volume, i.e. 40 horsepower is equal to 0.2 lbs/hr (probably not accurate but you get the idea). Adding more air doesn't get you more power once all the fuel is burned. Keeping the throttle open reduces pumping losses but the amount of power you lose going beyond stoichiometric is greater than what you save.

Propane has a stoichiometric ratio of about 15.6:1 but commercial propane is a mix of propane, methane, and butane. The actual ratio for any given tank of propane varies a bit.

I like what you are doing. This kind of experimentation is awesome and I am not trying to discourage you. Keep us updated.
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Unread 09-24-2013, 03:42 PM   #25
stovie
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There was this guy on another forum who made it so he could control the signal from the sensors to get his motor running as lean as possible and he also had a digital air/fuel ratio gauge but when he went up a steep hill he hit about 68-1 air/fuel ratio and turned his piston to slag!! That is not what I'm doing per say, he started rich and reduced fuel to get his lean mixture were as I'm starting lean and going rich to run the engine! If you look at the thermodynamic curve of gasoline it goes all the way to 4800 degrees then flattens out, they tell use the engine is at the 250 mark when idling but how is that when reducing fuel increases temperature and increasing fuel decreases combustion temperature!! The extra air isn't doing nothing it's there to absorb the heat making it so that it doesn't need to hit the same temp for the same power!! I mean how much of a temperature change is needed to make the same expansion in the cylinder when you have 10 times the air then when it was at 256 degrees??

Last edited by stovie; 09-24-2013 at 05:54 PM..
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Unread 09-24-2013, 11:27 PM   #26
zjosh93
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I'd be interested in seeing how he got a reading of 68:1 considering most wide band O2 sensors are only accurate to about 22:1. Yes, under lean conditions the extra air absorbs heat and increases in volume but the increase in volume from gasoline or propane burning and turning into water vapor and CO2 is much more significant than the heat expansion of air. Since the cylinder only intakes a certain volume per cycle the way you make it leaner isn't by adding more air, you are reducing the fuel, therefore reducing the amount of heat. All the heat and power comes from the fuel.

What I was trying to say before was that it takes a certain amount of energy to accelerate a ZJ up to say 30 mph. The way our engines work is to extract that energy from the atomic bonds in a complex hydrocarbon by combustion. The amount of energy stored in a unit of gasoline is constant and is fully extracted by adding stoichiometric air. Extra air doesn't participate in the reaction and so no additional energy is released. You would just be spreading the same energy over more mass. Since the ideal gas law (PV=NRT) is very true for or Jeep engines no additional work can be done by your extra air.

Again, not trying to discourage you. I love an adventurous spirit, it's what makes America great. I'm just cautioning you that many men have wasted fortunes trying to make 100 mpg carburetors when physics says that the energy isn't there.
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Unread 09-26-2013, 03:44 PM   #27
stovie
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Now that I think about it I think he said he did the calculation to see what it was, I think he said he figured out combustion temp, rpm's and a few other things to figure out the air/fuel ratio??? Another part of why I believe my experiment should work is I was building a house for a guy and it had no power on the job. So he brought his 12Kw diesel generator for use to use. One day when he came to do trim he filled it with gasoline accidentally and once the fuel got the the injectors that thing started screaming. It had a max rpm of 15,000 and he never had it scream like that! After shouting off the fuel(it was also at idle the whole time!!) it took about 30-45 minutes for it to stop. So then I got to thinking, if a diesel running of gasoline, at idle, can hit that high a rpm's then how much less fuel would get it to idle???
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