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propane injection in a soob?


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12 replies to this topic

#1 Zefy

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Posted 14 March 2004 - 01:06 AM

i have always heard people on this board wanting more power out of there soobs for off-roading...

i have been wanting to make a off-road chaser for about a month now and i was thinking about propane injection for i boost in the tough slots...

i have seen it in a chevy S-15... this thing could hall and could tow the school drag car on a trailer(probably around 4000lbs or more).

anybody tried this??? think the idea is crap??? anybody know how hard this would be??? i have know idea what it would take to do this so any help would be great!

thanks,

#2 GLCraig

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Posted 14 March 2004 - 01:39 AM

I know they do propane injection on diesel engines but I have never heard of it being done gas engine. The hardest part I think would be the pluming and the controls. Also you need to make sure that the liquid propane from the tank is 100% vapor before goes in the engine.

#3 asavage

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Posted 14 March 2004 - 01:55 AM

I can't see what injecting propane into a gas engine would do, other than FUBAR the mixture rich.

In diesel, it works (to a point, then it just melts things).

I can talk LPG (propane) conversion stuff till you're tired of hearing about it -- I own IMPCO parts sheets and install catalogs, I have several LPG mixers (300a, 425), a couple of vapourizer/regulators (Model E) and a couple vacuum filter/lockoff (VFF30), everything needed to do a basic gas engine conversion, except the high pressure line and tank.

But I don't think injecting propane into a gas engine with a functional/enabled carb or FI system would do anything other than overheat the cat from too much fuel.

Unless we're talking an aftermarket/homebrew turbo system, and then there are some limited applications for propane injection -- liquid, in that case. Very old-school.

The reason that some off-roaders like LPG is the freedom from fuel feed problems when the vehicle is at extreme angles. Plus the usual LPG benefits: very clean exhaust, very clean oil, higher octane so you can run higher compression, no choke anymore, sometimes cheaper fuel cost, etc.

#4 Danbob99

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Posted 14 March 2004 - 03:14 AM

actually, we ran a propane line out the window of my buddy's corolla (carbed), goin down the street we cranked the nob, and it picked up real quick. Nothing jaw dropping, but it was alright. I'm not so sure how he had it hooked up, mabey a straight line into the throttle body? dunno, i'm going to see him on monday, i'll ask him.

#5 oddcomp

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Posted 14 March 2004 - 10:45 AM

actually alot of current police cars a dual fuel systems

compressed natural gas and regular dino gas

kinda neat i had a chance to talk to a cop for a while about how the cars are set up
since at the time i sorta had nowhere to go ....

#6 asavage

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Posted 14 March 2004 - 03:13 PM

Dual-fuel: sure. CNG has a large federal and state subsidy -- it's not economical to run otherwise. You have to highly compress NG to get range, and the tanks are expensive and heavy. Neither are the case with LPG. But CNG has got the bux behind it, and municipalities are changing over metro buses to CNG in waves.

Dual-fuel does not imply that both fuels are being used simultaneously. IMPCO (and others) have fuel management computer add-ons to let the stock electronics work with multi-fuels.

Corolla: by adding propane, you moved the A/F ratio from the normal lean/clean condition to richer. He could have gotten the same boost from fudging the coolant temp sensor, probably.

Higher octane fuel doesn't get you more power unless you modify the engine to take advantage of it, and that's true of both gasoline and propane. Either advance the ignition timing or raise the CR, then higher octane fuel will have an impact on acceleration.

Propane is not magic, it's C3H8. Hydrocarbon. Less BTUs/unit (less energy-dense) than gasoline. Higher octane. A lot cleaner burning. But you aren't going to get a boost in output on an unmodified gasoline engine by dribbling it in, at least not if the engine is in proper tune.

#7 bigjim5551212

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Posted 14 March 2004 - 04:05 PM

With regards to propane. I was a member of the TDI club for VW TDI and they talk about propane injection instead of water injecton. This is the same idea as Nitrous as well. So, I would say on high boost turbo applications, propane injection would be a good thing.

In Vancouver here and a lot of places in Canada, propane is used as a single fuel motor fuel. Reasons
1)Cost. for say a Fed Ex or UPS truck or a taxi that runs around town all day, the cost is about 1/2 off gasoline.
2)Pollution. Much less pollution that gasoline.
3)Range. With a couple engine mods ie increased compression. You can have a larger range than gasoline, if you have the correct tanks.
4)Power, if you increase the compression to 12-1 or run a turbo on stock compression, you have the benefits of increased power

#8 asavage

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Posted 14 March 2004 - 05:17 PM

Originally posted by bigjim5551212
With regards to propane. I was a member of the TDI club for VW TDI and they talk about propane injection instead of water injecton.

Water injection has several benefits, but the major ones WRT turbo use are cooling the intake charge, supression of preignition, and cleaning the intake/combustion chamber of deposits. Actually, these all apply to non-turbo as well. I'll come back to WI vs Propane injection down below.

This is the same idea as Nitrous as well.

Um, no.

Nitrous Oxide does not burn, is not a fuel. It is an efficient carrier of oxygen to the combustion chamber. Free air is about 21% oxygen. NO2 is . . . a higher percentage oxygen.

Inject NO2, add also more fuel, get it all into the combustion chamber, and you get more power.

An additional benefit of conventional NO2 systems is that it is stored compressed, and when it's injected, it's also changing to a lower pressure, absorbing heat in the process. You get a brief intercooler effect -- cooler = denser + less susceptible to preignition.

Nitrous is not, in itself, an octane modifier.

Propane, OTOH, is a naturally high-octane hydrocarbon. It can be oxidized (burned). It's a fuel. If added to an already running gasoline engine, all it does is make the mixture richer. That's why it's commonly used as a diagnostic tool to find intake system vacuum leaks. It's generally pointless to add propane to a gasoline-fuelled engine that is actually running on gasoline.

Now, the situation is different for supplemental propane use in diesels. Though I know diesel and I know propane, and do not know much about the combination of the two, other than it's a very old idea (Google on "red rooster diesel", for example) and that it's back in vogue again, and from the very little I've read about it, the add-on kits being assembled and/or sold (esp. on eBay with single-step controls) have great potential to turn a diesel into scrap iron fast -- care and prudence is needed!

The situation WRT propane and TDi is not comparable to propane addition to a gasoline engine: apples & oranges.

Water injection on a turbodiesel will result in cooler exhaust temperature. Propane injection will significantly raise the exaust temperature. If interested, Google on "diesel exhaust temp" or "diesel pyrometer" for more info on why this might be a Bad Thing.

So, I would say on high boost turbo applications, propane injection would be a good thing.

I completely agree. For high boost, low boost, no boost applications, for a spark-ignition engine, propane is great.

In Vancouver here and a lot of places in Canada, propane is used as a single fuel motor fuel. Reasons
1)Cost. for say a Fed Ex or UPS truck or a taxi that runs around town all day, the cost is about 1/2 off gasoline.
2)Pollution. Much less pollution that gasoline.
3)Range. With a couple engine mods ie increased compression. You can have a larger range than gasoline, if you have the correct tanks.
4)Power, if you increase the compression to 12-1 or run a turbo on stock compression, you have the benefits of increased power


I just want to add that the cost differential situation is not the same in the US. We pay road tax on all fuels that are not used off-road. While there are methods to avoid this, for the mass-market, the cost per mile using LPG in the US is (currently) not a whole lot different that when using gasoline.

#9 Snowman

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Posted 14 March 2004 - 09:18 PM

In a diesel, supplemental propane injection acts as a catalyst for the diesel fuel when it is introduced. It wouldn't be the same for a gasoline engine.

#10 asavage

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Posted 15 March 2004 - 03:53 PM

Originally posted by Snowman
In a diesel, supplemental propane injection acts as a catalyst for the diesel fuel when it is introduced.


Bet you $10 propane does not act as a catalyst to diesel. Ever. Though you'll find a lot of people saying that's what it does. The word "catalyst" has a specific meaning WRT chemical reactions. In general, catalytic materials are not consumed during the reaction.

Propane, introduced into a diesel's intake tract, does:

* displaces air. If your diesel is already running in a condition where there is not a lot of excess air available, you'll get increased PM (particulate emissions)

* cannot self-ignite on compression, because there's not enough of it -- it's too lean a mixture

* burns with the diesel, once the diesel fuel ignites and spreads.

Though I haven't researched it, I'd hazard a guess than propane injection on a diesel might have a similar effect to raising the cetane rating of the base diesel.

#11 Brock Samson

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Posted 22 February 2012 - 11:22 PM

we were pretty close to putting the propane system from our 86 dodge omni in the 80 brat until we got the factory carb working ok finally. Running it on propane is a simple switch if you have the parts (tank lines regulators and carb)
it will run, run clean, run all the time. not as much power though unless you raise the compression ratio somehow. different pistons or shaved heads.

#12 ivans imports

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Posted 23 February 2012 - 11:20 AM

we are running a ej2.5 turbo on propane simpifyed the wire harnes down to crank sensor cam senser ig mod and knock senser thats it it runs a mixer of a chevy v8 work very good no problems and seems to make more power have run a deul feul setup on a ez3.0 turbo six cly worked good but had to use a very large mixer of 440 dodge to get enuff feul that moter had no rpm limit reved to 8500 rpms was crazy powerfull and flick aswitch and propane is off and runs on gas the only differance was the propane had no rev limit and i think it supplyed more feul than gas could but was very reliabble and resanabley safe mind you we brke two pistons but they are very week pistons in that engine

#13 Brock Samson

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Posted 23 February 2012 - 02:40 PM

wow! it would be great to see alot of high res pictures of that.




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