Propane
Propane
I just ran a 1/4" fuel line from the rubber elbow going into the turbo to a 20 lb BBQ propane cylinder sitting on the floor of the passenger compartment. I used a regulator that is adjustable from 0-30 psi. Driving to work I go up a decent hill so at about 60 mph I just slowly started adding propane and it just slowly started accelerating, very smoothly, no knocking or pre ignition, just like I was pushing on the accelerator. Experimenting, I was adding quite a bit, enough to make the regulator quite cold and still no scary noises what so ever. I had to back off on the accelerator quite a bit to maintain under 70.
Next I'm going to do it 'properly'. Turn up the boost to 12-14 psi and add a solenoid switch that opens a valve around 7 or 8 psi to allow the propane in. That way it will just be used when I need more power. I figure this is an easier way to get more fuel than a superpump. I know it won't be nearly as much power but it will be a hell of a lot cheaper!
Anyway, just thought I'd let you know that it won't blow your engine up like some people think. Just don't use it at idle...
Mostly out of boredom I decided to rig up a redneck propane injection for the '85 300CD. And it works great! There isn't much info out there on propane and IDI diesels so I figured what the heck, I'll give it a shot.
I just ran a 1/4" fuel line from the rubber elbow going into the turbo to a 20 lb BBQ propane cylinder sitting on the floor of the passenger compartment. I used a regulator that is adjustable from 0-30 psi. Driving to work I go up a decent hill so at about 60 mph I just slowly started adding propane and it just slowly started accelerating, very smoothly, no knocking or pre ignition, just like I was pushing on the accelerator. Experimenting, I was adding quite a bit, enough to make the regulator quite cold and still no scary noises what so ever. I had to back off on the accelerator quite a bit to maintain under 70.
Next I'm going to do it 'properly'. Turn up the boost to 12-14 psi and add a solenoid switch that opens a valve around 7 or 8 psi to allow the propane in. That way it will just be used when I need more power. I figure this is an easier way to get more fuel than a superpump. I know it won't be nearly as much power but it will be a hell of a lot cheaper!
Anyway, just thought I'd let you know that it won't blow your engine up like some people think. Just don't use it at idle...
whitey1986
07-12-2015, 03:12 AM #2Propane has a high autoignition temperature compared to diesel and only burns when the diesel ignites. It also cools the intake charge too!
Would be interesting to set a 617 up on a dyno with a nice size turbo and only use LPG as the main fuel
1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km
1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD
Veeeeeeeeeery interesting. Especially since I was a "non-believer"
Would be interesting to set a 617 up on a dyno with a nice size turbo and only use LPG as the main fuel
1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km
1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD
(07-13-2015, 01:56 AM)NZScott Veeeeeeeeeery interesting. Especially since I was a "non-believer"
Would be interesting to set a 617 up on a dyno with a nice size turbo and only use LPG as the main fuel
It wouldn't run as the diesel is required to get the temperature up enough to also burn the propane. By all means use both though!
whitey1986
07-13-2015, 02:19 AM #4(07-13-2015, 01:56 AM)NZScott Veeeeeeeeeery interesting. Especially since I was a "non-believer"
Would be interesting to set a 617 up on a dyno with a nice size turbo and only use LPG as the main fuel
It wouldn't run as the diesel is required to get the temperature up enough to also burn the propane. By all means use both though!
![[Image: 208104.png]](http://badges.fuelly.com/images/sig-us/208104.png)
I like where this is going, I would like to learn more but I don't want to be the first one to blow up my engine in the process. Reading up on this on another forum theres an ideal maximum ratio for diesel to propane you don't want to go over. Diesel is a lean burning engine meaning even when you reach the smoke point around 18 afr other fuels like propane can still burn the excess O2. Somewhere over 75% diesel and 25% propane you start melting engine components so be careful. I wouldn't dream of trying this without an EGT gauge. Good luck.
(07-13-2015, 02:19 AM)whitey1986(07-13-2015, 01:56 AM)NZScott Veeeeeeeeeery interesting. Especially since I was a "non-believer"
Would be interesting to set a 617 up on a dyno with a nice size turbo and only use LPG as the main fuel
It wouldn't run as the diesel is required to get the temperature up enough to also burn the propane. By all means use both though!
Yea, you'd have to start it and let it idle on diesel
(07-13-2015, 04:03 PM)Petar The problem with prechamber engines and propane is that the ball inside the prechamber can get real hot. Hot enough to preignite the propane, before the diesel is injected. And that CAN cause engine damage. It might work it might not.
Yes - that's what I've said before to people, wouldn't want them to apply something commonly done to direct injection engines on these. But the OP hasn't experienced anything negative...yet, anyway
1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km
1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD
(07-13-2015, 02:19 AM)whitey1986(07-13-2015, 01:56 AM)NZScott Veeeeeeeeeery interesting. Especially since I was a "non-believer"
Would be interesting to set a 617 up on a dyno with a nice size turbo and only use LPG as the main fuel
It wouldn't run as the diesel is required to get the temperature up enough to also burn the propane. By all means use both though!
Yea, you'd have to start it and let it idle on diesel
(07-13-2015, 04:03 PM)Petar The problem with prechamber engines and propane is that the ball inside the prechamber can get real hot. Hot enough to preignite the propane, before the diesel is injected. And that CAN cause engine damage. It might work it might not.
Yes - that's what I've said before to people, wouldn't want them to apply something commonly done to direct injection engines on these. But the OP hasn't experienced anything negative...yet, anyway
1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km
1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD
The reason I believe it works, is that propane, hell all gasses, have a flammability range. They have to have a certain concentration in order to ignite, which is why your gas engine mis fires when it is too lean. So the amount of propane we are injecting is way too lean to be ignited even if there were a spark plug in the prechamber. It only burns once the diesel lights off and burns a bunch of the oxygen out and the remaining mixture becomes burnable for propane.
That's my theory anyway and so far I have driven it several days using a bunch of propane without any weird noises or issues. I just need some time to make it more automatic. I would like to reference the manifold pressure to the regulator so that as boost increases so does the propane volume. I'll need to experiment a little to see if that works ok.
I know the prechamber ball has been the main source of consternation for using propane on these engines, and it's a reasonable concern.
The reason I believe it works, is that propane, hell all gasses, have a flammability range. They have to have a certain concentration in order to ignite, which is why your gas engine mis fires when it is too lean. So the amount of propane we are injecting is way too lean to be ignited even if there were a spark plug in the prechamber. It only burns once the diesel lights off and burns a bunch of the oxygen out and the remaining mixture becomes burnable for propane.
That's my theory anyway and so far I have driven it several days using a bunch of propane without any weird noises or issues. I just need some time to make it more automatic. I would like to reference the manifold pressure to the regulator so that as boost increases so does the propane volume. I'll need to experiment a little to see if that works ok.
whitey1986
07-14-2015, 12:17 PM #9Hopefully you don't get to see your crankshaft or conrods anytime soon hehehe
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