adding propane to gasoline engine?

[dlk]

This week I put a T in my 3/8" ID propane line and added a second 1/4" hose running into the airbox. This was the cheapest and easiest way to increase the amount of propane running into my engine. I'm weighing the cylinder before and after to determine how many lbs of propane I'm using.

One tube delivers a gallon(5 lbs) of propane about every 125 miles at 60mph, two tubes delivered a gallon every 85 miles. Unfortunately, I only got 17 mpg in those 85 miles That's exactly what I would expect to get without the boost. I think I've exceeded the amount my fuel injection will compensate for. I believe the computer realized something was wrong, and reverted to open loop operation. Needless to say, I'm going back to one tube.

The jury's still deliberating, but this experiment is starting to look like it isn't really worth it. I can only substitute 1 gallon of propane every 4 or 5 gallons of gasoline used, and unless I can figure out a way to get the bulk price on propane, it'll be more expensive than running on gasoline alone.

 

[Donner]

Don't worry about it... It's an experiment, no? See, the thing I was talking about earlier is sticking with $$$$$ expensive gas, but just find other areas to cut back on. That doesn't mean to stop your R&D, it just means find concrete ways to save - cutbacks.

Are you going to continue with R&D? It seems like you're having a really interesting experience with it. Keep in mind gas prices continue to climb... so keep going if you can

 

[BrooklynBay]

The next step for would be to use natural gas which you could refill from home. I'm sure it would be cheaper than propane.

 

[dlk]

Natural gas? That'd be hard since we don't have gas heat, only electric upstairs and a woodburner in the basement. I have a friend who heats his house with propane, and he said he had his tank filled in the summer for about $1.50 a gallon. I just need to figure out how to get the bulk price on the propane, I would have to buy or lease a large tank.

I'll probably continue dinking around at least until it gets warm enough to drive my motorcycle, which gets 45-50 mpg and causes my exploder to sit for long periods of time during the summer

 

[dlk]

 

[ngrover]

I came across a "propane conversion kit" on the net today. Even though it costs more than pocket change I wonder what the result would be.
http://poweredbypropane.net/products/3.html

 

[dlk]

Well, it's spring now and my engine doesn't like getting propane in warmer weather. It makes the check engine light come on, so I guess I might have to resume my R&D in the fall. I might try to use #85 again. My understanding is that ethanol has less energy in it, so more is required to achieve the proper A/F mix, and maybe adding propane will help me achieve this. Gas is now 3.459/gal here, and E85 is 2.459, so that should make up for the cost of the propane if it works.

 

[BrooklynBay]

Did you see what code it was throwing?

 

[JCUZ]

I came across a "propane conversion kit" on the net today. Even though it costs more than pocket change I wonder what the result would be.
http://poweredbypropane.net/products/3.html

The results are great - I have one of these fitted to my 04 explorer 4.6. So far, fuel usage is roughly the same in MPG terms as gasoline, but here, LPG (propane) costs 70 cents per litre, and petrol is around $1.40 per litre. It takes around 12 to 18 months of fuel savings to pay for the kit, but thereafter it's all cheaper fuel! I don't believe these kits are legal in the USA though - but hey, you can run your cars on subsidised corn by-products (when ethanol made from sugar cane would be much cheaper).

Anyway. here's a pic or two of the kit fitted:
Converter and injectors for left bank:

LPG ECU:

 

[dlk]

Did you see what code it was throwing?

No, but I'm pretty sure it's because it was running too rich.

 

[ngrover]

The results are great - I have one of these fitted to my 04 explorer 4.6. So far, fuel usage is roughly the same in MPG terms as gasoline, but here, LPG (propane) costs 70 cents per litre, and petrol is around $1.40 per litre. It takes around 12 to 18 months of fuel savings to pay for the kit, but thereafter it's all cheaper fuel! I don't believe these kits are legal in the USA though - but hey, you can run your cars on subsidised corn by-products (when ethanol made from sugar cane would be much cheaper).

Cool, someone who has experience with one of these kits. I'm still considering the poweredbypropane kit. I'm just trying to figure out what the advantages / disadvantages are with respect to liquid propane injection (like the kits that Prins makes) vs the vapour injection like the poweredbypropane kits.

I live in Canada and have a few places near my house that sell auto-propane so I'm all set in that regard. It's legal and propane vs gasoline prices are the same here as they are for you ($1.30 vs $0.70)

How long does the vehicle normally have to run before it's hot enough to switch to propane from regular gas?

Which kit did you use?

 

[JCUZ]

Cool, someone who has experience with one of these kits. I'm still considering the poweredbypropane kit. I'm just trying to figure out what the advantages / disadvantages are with respect to liquid propane injection (like the kits that Prins makes) vs the vapour injection like the poweredbypropane kits.

I live in Canada and have a few places near my house that sell auto-propane so I'm all set in that regard. It's legal and propane vs gasoline prices are the same here as they are for you ($1.30 vs $0.70)

How long does the vehicle normally have to run before it's hot enough to switch to propane from regular gas?

Which kit did you use?

It changes over when engine temp hits 40 degrees Celsius - in winter here that's about 3 km. The kit I got is KME from http://www.kme.com.pl/EN_index.html.

If you are able to get liquid injection, go for it; it's around 20% better than vapour injection.

 

[ngrover]

It changes over when engine temp hits 40 degrees Celsius - in winter here that's about 3 km. The kit I got is KME from http://www.kme.com.pl/EN_index.html.

If you are able to get liquid injection, go for it; it's around 20% better than vapour injection.

Cool thanks I'll check out the kit you got. Who makes a good liquid injection kit? I think I've seen one by a company names Prins but I'm not sure if they make it for my engine. I have a 4.0 ohv with a plastic intake manifold... but I could prob swap out the plastic one for an older aluminum one. When you say 20% better do you mean power wise or mileage wise (or a bit of both)?

 

[JCUZ]

Cool thanks I'll check out the kit you got. Who makes a good liquid injection kit? I think I've seen one by a company names Prins but I'm not sure if they make it for my engine. I have a 4.0 ohv with a plastic intake manifold... but I could prob swap out the plastic one for an older aluminum one. When you say 20% better do you mean power wise or mileage wise (or a bit of both)?

LPG Liquid Injection (LPLI) has only just been released in Australia, but the results so far suggest that you get more power (around 5%) and the same economy as petrol. With my VSI/SVI system, I get around the same power, but I use about 20% more fuel to do it.

Prins are a well known brand of LPG kits, so if they have a LPLI system, then I'd say it would be OK. The injector size is the thing that is critical for the right fuel delivery, so I'd ask one or more of your local installers and see what they have to say. Also, with either SVI or LPLI, there's no issues with using the plastic manifold, as backfires are about as prevalent as they are on petrol (ie non-existent). It's only the old mixer ring/venturi style mixers where backfires are a real risk, as the fuel is delivered in the intake, and if it's not being burned, it builds up. With injection, it is injected directly into each cylinder - just like petrol. So if it doesn't all burn, it gets sucked out with the exhaust gasses and there is no buildup in the intake manifold, or piping.

 

[TrondOscar]

LPG conversion kit

I have had an LPG conversion kit installed to my 98 SOHC. It works like a charm - that is, I haven´t had time to run the numbers yet. It is made by an italian company called BRC, and was installed by gastech in Oslo, Norway. More or less the same as the Aussie´s Prins kit.

Will get back to you with pics and mileage when I have time - right now the cargo barrier is first priority due to a planned vacation where I´ll have to fill the trunk up to the roof...

 

[superfestiva]

I did a thread on my conversion...
http://www.explorerforum.com/forums/showthread.php?t=228249

the aussie's kit is a 4th gen LPG conversion and mine is 3rd gen...the 4th gen is expensive but is more reliable than the 4th gen since it uses sequential port injection controlled via computer...

In the Dominican Republic the 3rd gens have been here for almost a decade and the 2 nd gen which is obsolete have been here for decades...the 4th gen has been here for approx. 4 years...

Have not had any problems since this is my second time using a 3rd gen propane kit...the first was in a 99XLT and the second is in my 03 XLT...runs like a charm, saves tons of $$$, and you don't loose that much power but the enginer runs smoother and cooler...you can't feel it running when in idle...!!!
With this kit I can travel anywhere and not be afraid of gas consupmtion since LPG is so cheap!!!

 

[superfestiva]

LPG Liquid Injection (LPLI) has only just been released in Australia, but the results so far suggest that you get more power (around 5%) and the same economy as petrol. With my VSI/SVI system, I get around the same power, but I use about 20% more fuel to do it.

Prins are a well known brand of LPG kits, so if they have a LPLI system, then I'd say it would be OK. The injector size is the thing that is critical for the right fuel delivery, so I'd ask one or more of your local installers and see what they have to say. Also, with either SVI or LPLI, there's no issues with using the plastic manifold, as backfires are about as prevalent as they are on petrol (ie non-existent). It's only the old mixer ring/venturi style mixers where backfires are a real risk, as the fuel is delivered in the intake, and if it's not being burned, it builds up. With injection, it is injected directly into each cylinder - just like petrol. So if it doesn't all burn, it gets sucked out with the exhaust gasses and there is no buildup in the intake manifold, or piping.

I have had two third generation LPG conversion and yes they can backfire...BUT they backfire if one of the following:
-you have an electrical problem (ie., bad plugs, bad timing, ignition wires, etc.)
-you have an air problem (ie. intake, vacuum, etc.)
-you are running too lean on LPG meaning that the venturi mixer has to be in good condition (cleaned regularly) and you have to have it adjusted finely...

I know it is preferrable to have the 4th gen (specially since the intake manifold is plastic) but the 3rd gen can work if you maintain it good...