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Propane Injection
by
Toby
on 06 Apr, 2011 01:16
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Has anyone here messed with propane injection? I suspect I could do it with a propane regulator modified to dump propane proportionally to a boost reference. I have read the ads and "testimonials" but if is all magical thinking and mountain medicine I would not be very interested in wasting my time playing with it.
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#1
by
RabbitJockey
on 06 Apr, 2011 04:31
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it has been tried many years ago and i think alot of people had bad luck with it detonating, but if someone wants to do the research and find out what it takes to make it work, that would be awesome, i think our engines are too high compression and with the prechamber being pretty hot at all times it causing predetonation, but i could be wrong
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#2
by
mullenba
on 06 Apr, 2011 06:53
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#3
by
RadoTD
on 06 Apr, 2011 07:23
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I'm contemplating trying it, for performance and not to increase fuel economy.
My plan is to run a 1lb bottle (which actually has a significant runtime for what I need), make a regulator for it and control it from a progressive nitrous controller. I won't do it until I've got the car on a dyno and can tune it there. Whatever RPM my torque starts to drop, I'll progressively inject it, likely up to about a 20hp shot. I'll also only have it come one when I'm at or near full throttle and boost is at or near my max. So I'll probably have a progressive shot from 0 to 20hp worth of propane over 2 seconds or so from 4000rpm and up.
The advantages I see are cooled intake charge from the propane expanding from a liquid to a gas, capacity for more fuel (power) without going to a pump with a larger head on it and the big one, being how the propane will burn. Diesel burns slowly and moreso in an IDI than TDI, burns away from a single point. All the diesel is injected in the prechamber, where *most* of your air will/should be, but there is more air all through the combustion chamber. Particularly at higher rpm's, the diesel can't sweep through the whole combustion chamber and burn all the air you have. You end up smoking at very high Air:Fuel ratios. Propane on the other hand burns quickly and is evenly dispersed with the air. Once ignited by the diesel, it'll quickly burn the whole way through the combustion chamber and hopefully help burn more of the air I'm pumping in.
Auto ignition temp is 540*C compared to diesel's 225*C and it doesn't ignite well at low air/fuel mixtures. If you turn your BBQ on full and toss a match down onto the coals, it's actually difficult to light, it needs a rich enough mixture to actually ignite. Someone I know has run propane on a diesel before and said under 15% he had no trouble with predetonation. He did get bored, turned it up and ended up blowing the head right off the engine from predetonation though. Predetonation of the propane is certainly my biggest fear in running this setup
Just my 2c
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#4
by
RabbitJockey
on 06 Apr, 2011 08:56
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and what kind of diesel was he running propane on? i know on bigger engine slike the fords and cummins they do it, but those are direct injection engines and also have much lower compression ratios.
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#5
by
R.O.R-2.0
on 06 Apr, 2011 09:00
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and what kind of diesel was he running propane on? i know on bigger engine slike the fords and cummins they do it, but those are direct injection engines and also have much lower compression ratios.
Propane + IDI = generally a bad idea...
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#6
by
zukgod1
on 06 Apr, 2011 11:25
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I suspect the principals of running propane is pretty close as natural gas.
I have a Natural gas system sitting here I'm wanting to try on my Caddy with the new engine. There are several things that need to take place before I get that far but still on the notebook.
I will be using a vac operated system that runs off the 2-3" of vac in the intake (front of turbo). The only electrical components are the safety relays to deactivate it if needed.
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#7
by
RadoTD
on 06 Apr, 2011 13:18
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and what kind of diesel was he running propane on? i know on bigger engine slike the fords and cummins they do it, but those are direct injection engines and also have much lower compression ratios.
Hmm... maybe not worth the risk?
Or a good excuse to find a cummins 4bt pump instead
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#8
by
keaton
on 06 Apr, 2011 17:49
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I'm contemplating trying it, for performance and not to increase fuel economy.
My plan is to run a 1lb bottle (which actually has a significant runtime for what I need), make a regulator for it and control it from a progressive nitrous controller. I won't do it until I've got the car on a dyno and can tune it there. Whatever RPM my torque starts to drop, I'll progressively inject it, likely up to about a 20hp shot. I'll also only have it come one when I'm at or near full throttle and boost is at or near my max. So I'll probably have a progressive shot from 0 to 20hp worth of propane over 2 seconds or so from 4000rpm and up.
The advantages I see are cooled intake charge from the propane expanding from a liquid to a gas, capacity for more fuel (power) without going to a pump with a larger head on it and the big one, being how the propane will burn. Diesel burns slowly and moreso in an IDI than TDI, burns away from a single point. All the diesel is injected in the prechamber, where *most* of your air will/should be, but there is more air all through the combustion chamber. Particularly at higher rpm's, the diesel can't sweep through the whole combustion chamber and burn all the air you have. You end up smoking at very high Air:Fuel ratios. Propane on the other hand burns quickly and is evenly dispersed with the air. Once ignited by the diesel, it'll quickly burn the whole way through the combustion chamber and hopefully help burn more of the air I'm pumping in.
Auto ignition temp is 540*C compared to diesel's 225*C and it doesn't ignite well at low air/fuel mixtures. If you turn your BBQ on full and toss a match down onto the coals, it's actually difficult to light, it needs a rich enough mixture to actually ignite. Someone I know has run propane on a diesel before and said under 15% he had no trouble with predetonation. He did get bored, turned it up and ended up blowing the head right off the engine from predetonation though. Predetonation of the propane is certainly my biggest fear in running this setup
Just my 2c
please have a video camera handy when you do this. i always love to watch people blow their motors up.
you should read up on it some more. if you want a 20hp shot use Nitrous not propane. propane increase the flame front which is good for reducing fuel consumption as it allows for a more complete burn, as a result you gain more power and higher EGTs.
you will not be able to dump liquid propane into your motor, well you can you just might not like the results. liquid propane expands 20:1
read this
http://www.mrsharkey.com/lpg.htmother thread on this subject
http://www.vwdiesel.net/forum/index.php?topic=5300.0
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#9
by
rabbitman
on 06 Apr, 2011 18:42
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A local guy here has a homemade propane system on his '91 eco jetta. He has a toggle switch on the dash to turn it on and off
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He said that at idle it'll almost stall the engine but when he's going down the road he can hold higher gears than normal on hill and pass people easier. When left on the 1lb tank lasts less than 100 miles.
I did tell him that a go pedal switch would be way better and allow the head to remain bolted to the block longer..........
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#10
by
RabbitJockey
on 06 Apr, 2011 18:50
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i think its ok on idis, but u gotta have it setup right, i was reading they do use them on the older idi fords and gm engines, and those have similar compression ratios
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#11
by
RadoTD
on 06 Apr, 2011 19:16
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please have a video camera handy when you do this. i always love to watch people blow their motors up.
you should read up on it some more. if you want a 20hp shot use Nitrous not propane. Propane is a fuel, nitrous is an oxidizer. If I want more oxygen, I can turn my boost up... my turbos will be able to efficiently give me over 40psi. Fueling to match that would likely lift/warp my head or blow something in the bottom end out. I don't need more oxygen, I want to be able to burn better at higher RPM's
propane increase the flame front which is good for reducing fuel consumption as it allows for a more complete burn, as a result you gain more power and higher EGTs. I was under the impression that due to the more complete burn, it actually lowered EGT's? I could definitely be wrong here though.
you will not be able to dump liquid propane into your motor, well you can you just might not like the results. liquid propane expands 20:1 I was more referring to dumping the liquid into my intake, preferably after the intercooler. If my solenoid is close enough to the nozzle, the propane will still be expanding as it enters my charge plumbing, reducing the charge temps. I wasn't referring to actually injecting liquid into the motor, sorry if it came across that way
read this
http://www.mrsharkey.com/lpg.htm I have read that, he's doing that on an IDI VW engine. On page 4, he's running 16% propane on one car, without predetonation. Say I'm at 180whp before propane, 16% of that is nearly 30hp worth of straight propane, likely closer to a 40hp difference due to the more complete combustion
other thread on this subject
http://www.vwdiesel.net/forum/index.php?topic=5300.0 Thanks for that link, I'll have to read through that one
On the first line of my original post, I said that I'm contemplating trying propane. There are a lot of guys on this forum with more knowledge than me, so I wasn't going to try it without throwing the idea out there... I'm still running break in oil on my engine chasing small electrical bugs. I don't even have my intercooler hooked up yet, so I've got a while to figure out exactly what I'm going to do to my motor
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#12
by
dodger21
on 06 Apr, 2011 19:57
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Propane is a horrible cost=power=efficiency ratio compared to water/meth and nitrous. To efficiently get more fuel, turn the screw or get a Giles pump. Don't want the low boost fueling? Install a valet switch inline to the LDA air inlet. Turn it on for 0-2lbs of boost entering diaphragm, or off to allow full fueling.
Nobody in the competition diesel truck world even thinks of propane. Heck, the only people using it are long haul mileage record breakers in the truck world replacing diesel once at desired speed with propane. They literally have the fueling down so low that the primary fuel is propane/natural gas. The only way they are doing this effectively is for the ones with ECM control of the injection pump/quantity.
Too much fuel resulting in high EGTs? Water injection, with a bit of meth for an added boost.
A lot of fuel and not enough turbo? Nitrous hand down.
You say your turbo can efficiently boost up to 40psi. You have a map for me to look at? Thanks!
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#13
by
keaton
on 06 Apr, 2011 21:43
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I was more referring to dumping the liquid into my intake, preferably after the intercooler. If my solenoid is close enough to the nozzle, the propane will still be expanding as it enters my charge plumbing, reducing the charge temps. I wasn't referring to actually injecting liquid into the motor, sorry if it came across that way
maybe something like this
http://www.designengineering.com/category/catalog/cryo2-system-components/cryo2-air-intakein line CO2 air charge cooler. maybe you can use that as your liquid expander then fog pre turbo
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#14
by
RadoTD
on 06 Apr, 2011 22:34
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