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Discussion Starter #1 (Edited)
Since I'm trying to do this, I'd figured I'd share with all of you. If the setup works, I'd also like to know how interested people would be in purchasing such a setup. Demand or no I plan to do it for my car, but it would be good to know up front if I should be prepared to make a kit out of it.

I should note up front, if it does become possible, will almost certainly require a AEM EMS to run it.

So the main question is, why? Some reasons:

1. 104 octane, need I say more?

2. Perfect atomization. Because propane exists as a vapor in the engine, it will always be fully vaporized. This has major benefits, or shall I say, doesn't have all the problems gasoline does.

Starting: Ever wonder why cars don't start so well when they are cold? Or why a gasoline engine requires a much richer AFR during starting and warm up? It's due to poor atomization. Gasoline doesn't burn, gasoline VAPOR does. The less atomization that occurs, the less gasoline is available to combine with oxygen. Heat encourages gasoline vaporization. Which is why at full operating temp, gasoline does pretty good. It's hitting hot valves, hot combustion chamber surfaces, etc, and the compression cylce is hotter which also promotes very good (but still not perfect) atomization by the time of ignition. On a cold engine, gasoline tends to stay in drops, which won't burn. Rather they get wasted and go out the tailpipe. This is why a 12:1 or so ratio is needed during warm-up, and cold cranking has a ratio of like 9:1 or so. You need all the extra fuel just to get enough vapor to start combustion. The extra fuel also hurts the combustion when it finally does occur, same reason cars lose power past 12:1, the extra fuel "gets in the way."

With propane, all these problems vanish. It will be a vapor down to -50F. No extra fuel should be needed for starting and warmup. You should be able to crank it over at 30F with the same stoich AFR as it idles at 180F coolant.

3. No potential for wash down. When starting a gasoline motor, or if for any reason the motor is run way too rich, the extra fuel collects on the cylinder walls and can cause "wash down," basically washing away lubrication and causing damage. This can't happen with propane, as it will always be a gas in the motor.

4. Cleaner engine, MUCH lower emmisions. Gasoline also requires (and at the pump it contains) a number of lubricants to protect the pump, injectors, and partially the cylinder walls. The burned lubricants are a main contributor to carbon deposits, and oil contamination, and lots of the stuff that shows up in a emmisions test. With propane, no burnt lubricants, no carbon deposits, and the emmisions will be MUCH lower. I'd be willing to guareentee any single turbo MKIV with NO cat should be able to pass a sniff test on propane. Oil should also stay looking clean for up to 10,000 miles.

5. Horsepower. Here I know people will step in with some information that propane doesn't make as much power. That is very misleading. By and large propane conversions have been, and continue to be, very primitive. The metering of fuel is very poor, leaving super rich AFRs under many conditions, which robs power. Similarly, ignition settings are never adjusted. Propane having different burn characteristics and octane than gas, requires different ignition settings. Staying with ignition curves made for gas results in more power loss. The system I'm working on will not have these factors hurting. AFR will be controlled precisely, and ignition will be optimized. On paper, propane should make more power with a given air mass. Here's why:

Propane 21,591 BTUs/lb
Gasoline 18,400 BTUs/lb

Propane, stoich 15.7:1 AFR
Gasoline, stoich 14.7:1 AFR

21591/15.7=1375.223 BTUs/lb of stoich propane air:fuel mix
18400/14.7=1251.701 BTUs/lb of stoich gasoline air:fuel mix

1375.223/1251.701=1.099 or about 10% more power with propane from the same mass air flow of air.

Some of this power is offset by the fact that propane is already a gas occupying space in the incoming air, where gasoline does some of it's vaporization inside and some outside the cylinder. But the power potential is certainly higher with propane.

6. Electric consuption. In the case of the system I have planned, electrical power consumption for the whole system will be about 1-2amps. That's it. Compare to a upgraded fuel system, which uses about 20-30amps at full blast (injectors + two fuel pumps).

7. Flow. This would be a replacement for a fuel system. Flows of up to 1000RWHP shouldn't be a problem.

8. Usage Cost. This is a fuzzy subject. By the pound, propane certainly has more energy in it than gasoline. However, by the liquid gallon, propane has about 20% less BTUs/gal. With current prices, which have propane about the same price as 87 pump gas, and $.20 cheaper than 92, it works out to cost maybe 5% more/mile than premium gas. But compared to 104 pump gas, it's a LOT cheaper. Also keep in mind that we are at a very high price point for propane. For the previous 20 years, propane has nearly always been about 20% cheaper than regular pump gas. So expect the gas/propane price disparity to improve.

9. Purchase cost. Be a lot cheaper than a fuel system. I'd probably price it under $1000 for a complete conversion, able to support up to 1000RWHP.

10. Simplicity. One line, one valve, one injection point, one electrical connection. Compared to two feed lines, one return, rail, six injectors, six injection points, six electrical connections, etc.

11. Weight. If you are crazy about weight savings, you can drop your gasoline tank out and save about 30lbs, and another 5lbs or so by removing the lines, rail, injectors.

12. No more pump gas. If you do some reading, you will discover you aren't buying just gas at the pump. You are buying a mix of god knows what. Every station can have a different mix. Changes with state, city, and time of year. MTBE, ethanol, the list of things they already have in there is endless. MTBE for instance, will reduce the horsepower than can be made on that fuel. There can be up to 15% MTBE in some gas. The constant changes also effects the burn rate and combustion efficiency. The ideal ignition timing to make max power on one blend will differ with another.

Propane, since it's sold mostly to people with BBQs in use for food preparation, is sold very clean. You buy just propane when you buy propane. Tuning for max power won't be hurt by variances in the fuel.
 

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The porblem I could see you running into is vapor displacement. As you mentioned propane has a lower BTU/gal. This means that you will have to inject a larger volume of propane than you would gasoline. As I am sure you know this fuel will take the place of air. Other than that it will elliminate any issues with unvaporized fuel. Also, I am sure you are aware that this vapor displacement is not the sole reason cars lose power past 12:1 A/F. The combustion efficiency drops rapidly with anything richer than stoich. Anyway, it sounds promising.

Good luck,
Daniel
 
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Discussion Starter #5 (Edited)
SupraWood, yes I made mention of the displacement issue. Gasoline does it too, it's just real hard to say how much. The placement of the injectors, heat of the surfaces, time the injector is open vs closed, quality of the spray, etc all effect the ratio of gasoline vaporization before:after the intake valve.

The short answer is in a stoich mixture, propane vapor occipies 4% of the total volume. So we got a 10% gain through the higher Btus, and lose 2-4% through the volume displacement. Sounds good to me.

Yes I knew that combustion efficiency goes down with over rich mixtures, of any fuel. That brings another intesting topic up.

Gasoline is run at 12:1 under boost for two reasons:

1. Not all gasoline vaporizes, and some is wasted. Extra is needed to be sure all the oxygen is utilized.
2. Extra fuel helps add a little cooling, to combat knock.

Propane has neither of these reasons. Since we have a perfectly mixed vapor of air and propane, no extra fuel beyond stoich should produce additional power. So goes the theory. We have plenty of octane that cooling shouldn't be a factor. So we should be able to run a stoich mixture, and gain quite a bit of combustion efficiency over gasoline, and run far less of it. This theory will be tested if I get the system up and running on my car.

ppalamara, how many of us with highly modded cars are perfectly street legal anyway? Ya know, "off road" use only? ;)

Besides, what do all the propane fleet vehicles and RVs do? Take the long way around? I doubt it.

If you want to run E85, it's not much different than gasoline really. Just size everything 50% bigger, and it should be the same as gas. You could run a VPC with a 720cc chip with 1000cc injectors and it would run fine. The pump setup should match the injectors, just like any fuel system.
 

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Yes, a rich mixture is needed to avoid knock, but it also provides more power for a couple reasons:
1. A slightly rich mixture will burn faster than a stoich
2. BHP is a function of F/A and combustion efficiency. This is what is being traded off. Unfortunately the losses in combustion efficiency are greater than the added energy in the fuel past 12:1.

For these reasons running a mixture leaner than ~12:1 will not yield more power. It will decrease even if knock were not the problem. The only reason engines run at stoich is for emissions. Other than that there is no reason to strive for a stoich combustion.

I agree that not all of the fuel is used, but typically most of the unvaporized fuel never makes it into the engine (it just forms a "puddle")....at least on a fully warmed up port injected engine. Certainly on warm up this is a huge problem.

Daniel
 
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Discussion Starter #7 (Edited)
SupraWood, I disagree with those. They hold true for gasoline, because of it's liquid nature. Assuming fuel in full vapor form, and perfectly mixed with air, stoich mixtures will burn faster and more efficienctly. The reason gas runs better richer, is because not all of the injected fuel is sitting at the ready to combust with oxygen. But with gaseous propane, stoich should be better.

Of course, we are arguing against a brick wall until I can test it. If I have to run propane 20% richer than stoich for max power like gasoline, or if I run stoich for max power, doesn't change that propane still rocks. Let's just wait and see. In all likelihood, I expect it to be somewhere in between, 5-10% richer than stoich.

On the subject of puddling, true for most engines perhaps. But on the 2JZ, there is no where for the gasoline to puddle. Look at the ports and injector placement. Any puddling that occurs will get sucked in on the next intake stroke. Which I should mention, occurs at anything over 30% duty on the injectors. Past that point, the injectors are just creating a big puddle on top of the intake valves, which drops into the cylinder when the valves open. Not a great scenario for atomization.
 

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I wish you the best of luck. The two things I mentioned were out of my ME437 class...so... The first one could be more due to the excess fuel like you said, but the second one is out of an equation. Like I said it is promising, and I would like to see what happens.

Has anyone ever made more power with propane? Not to burst any bubbles, but it seems unlikely that this is so revolutionary that you could be the first person to make more power with propane.

Daniel
 
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Discussion Starter #9
Yes, one company with a very advanced delivery system ($2600)made almost 10% more power on propane than gas. I'll see if I can find the article again.

I found a interesting webpage that explains in detail a lot of the things that occur in the cylinder, and how the fuel composition (namely gas being a liquid) relates to that. In reading it, you can see how advantageous a vapor fuel is to a liquid one.

http://www.yawpower.com/jultech.html
 

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Absolutely people have made power on Propane! There was a raod racing Mustang in several mags years ago running on nothing but propane with great results. I cannot recall the name of the shop fielding it but it was a supercharged Mustang running pretty darned good. It injected liquid propane I believe and not vapor so the phase change occured at the engine which dropped temps bigtime. It also meant smaller injectors too - it used just a couple of HUGE propane injectors.

Biggest problem I see - storage. You will burn more volume of propane than you would gasoline. Storing enough to drive far will be an issue IMO.
 

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BLKMGK said:

Biggest problem I see - storage. You will burn more volume of propane than you would gasoline. Storing enough to drive far will be an issue IMO.
Thats the same thing I was worrying about while reading this. What were your ideas for this Derek? Best of luck with the project, it sounds great
 

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how heavy is a standard charcoal grill propane container?

also, how safe is propane to have in-car? i don't want my car to exhibit the "hollywood effect," where all cars tend to explode in a huge fireball whenever in a fender-bender. :eek:
 

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AnArKey said:
Since I'm trying to do this, I'd figured I'd share with all of you. If the setup works, I'd also like to know how interested people would be in purchasing such a setup. Demand or no I plan to do it for my car, but it would be good to know up front if I should be prepared to make a kit out of it.

I should note up front, if it does become possible, will almost certainly require a AEM EMS to run it.

So the main question is, why? Some reasons:

1. 104 octane, need I say more?

2. Perfect atomization. Because propane exists as a vapor in the engine, it will always be fully vaporized. This has major benefits, or shall I say, doesn't have all the problems gasoline does.

Starting: Ever wonder why cars don't start so well when they are cold? Or why a gasoline engine requires a much richer AFR during starting and warm up? It's due to poor atomization. Gasoline doesn't burn, gasoline VAPOR does. The less atomization that occurs, the less gasoline is available to combine with oxygen. Heat encourages gasoline vaporization. Which is why at full operating temp, gasoline does pretty good. It's hitting hot valves, hot combustion chamber surfaces, etc, and the compression cylce is hotter which also promotes very good (but still not perfect) atomization by the time of ignition. On a cold engine, gasoline tends to stay in drops, which won't burn. Rather they get wasted and go out the tailpipe. This is why a 12:1 or so ratio is needed during warm-up, and cold cranking has a ratio of like 9:1 or so. You need all the extra fuel just to get enough vapor to start combustion. The extra fuel also hurts the combustion when it finally does occur, same reason cars lose power past 12:1, the extra fuel "gets in the way."

With propane, all these problems vanish. It will be a vapor down to -50F. No extra fuel should be needed for starting and warmup. You should be able to crank it over at 30F with the same stoich AFR as it idles at 180F coolant.

3. No potential for wash down. When starting a gasoline motor, or if for any reason the motor is run way too rich, the extra fuel collects on the cylinder walls and can cause "wash down," basically washing away lubrication and causing damage. This can't happen with propane, as it will always be a gas in the motor.

4. Cleaner engine, MUCH lower emmisions. Gasoline also requires (and at the pump it contains) a number of lubricants to protect the pump, injectors, and partially the cylinder walls. The burned lubricants are a main contributor to carbon deposits, and oil contamination, and lots of the stuff that shows up in a emmisions test. With propane, no burnt lubricants, no carbon deposits, and the emmisions will be MUCH lower. I'd be willing to guareentee any single turbo MKIV with NO cat should be able to pass a sniff test on propane. Oil should also stay looking clean for up to 10,000 miles.

5. Horsepower. Here I know people will step in with some information that propane doesn't make as much power. That is very misleading. By and large propane conversions have been, and continue to be, very primitive. The metering of fuel is very poor, leaving super rich AFRs under many conditions, which robs power. Similarly, ignition settings are never adjusted. Propane having different burn characteristics and octane than gas, requires different ignition settings. Staying with ignition curves made for gas results in more power loss. The system I'm working on will not have these factors hurting. AFR will be controlled precisely, and ignition will be optimized. On paper, propane should make more power with a given air mass. Here's why:

Propane 21,591 BTUs/lb
Gasoline 18,400 BTUs/lb

Propane, stoich 15.7:1 AFR
Gasoline, stoich 14.7:1 AFR

21591/15.7=1375.223 BTUs/lb of stoich propane air:fuel mix
18400/14.7=1251.701 BTUs/lb of stoich gasoline air:fuel mix

1375.223/1251.701=1.099 or about 10% more power with propane from the same mass air flow of air.

Some of this power is offset by the fact that propane is already a gas occupying space in the incoming air, where gasoline does some of it's vaporization inside and some outside the cylinder. But the power potential is certainly higher with propane.

6. Electric consuption. In the case of the system I have planned, electrical power consumption for the whole system will be about 1-2amps. That's it. Compare to a upgraded fuel system, which uses about 20-30amps at full blast (injectors + two fuel pumps).

7. Flow. This would be a replacement for a fuel system. Flows of up to 1000RWHP shouldn't be a problem.

8. Usage Cost. This is a fuzzy subject. By the pound, propane certainly has more energy in it than gasoline. However, by the liquid gallon, propane has about 20% less BTUs/gal. With current prices, which have propane about the same price as 87 pump gas, and $.20 cheaper than 92, it works out to cost maybe 5% more/mile than premium gas. But compared to 104 pump gas, it's a LOT cheaper. Also keep in mind that we are at a very high price point for propane. For the previous 20 years, propane has nearly always been about 20% cheaper than regular pump gas. So expect the gas/propane price disparity to improve.

9. Purchase cost. Be a lot cheaper than a fuel system. I'd probably price it under $1000 for a complete conversion, able to support up to 1000RWHP.

10. Simplicity. One line, one valve, one injection point, one electrical connection. Compared to two feed lines, one return, rail, six injectors, six injection points, six electrical connections, etc.

11. Weight. If you are crazy about weight savings, you can drop your gasoline tank out and save about 30lbs, and another 5lbs or so by removing the lines, rail, injectors.

12. No more pump gas. If you do some reading, you will discover you aren't buying just gas at the pump. You are buying a mix of god knows what. Every station can have a different mix. Changes with state, city, and time of year. MTBE, ethanol, the list of things they already have in there is endless. MTBE for instance, will reduce the horsepower than can be made on that fuel. There can be up to 15% MTBE in some gas. The constant changes also effects the burn rate and combustion efficiency. The ideal ignition timing to make max power on one blend will differ with another.

Propane, since it's sold mostly to people with BBQs in use for food preparation, is sold very clean. You buy just propane when you buy propane. Tuning for max power won't be hurt by variances in the fuel.
Looks like you did a lot of research... but you really don’t have a clue as you what you’re up against.

I don’t want to sound like an ass but I have been designing and building alternative fuel components and delivery systems since the early 90's. I'll also sell over a million gallons of Propane this year retail/wholesale, so I know my gas.:)

I might have some time this weekend if you want to turn this into a c3h8 nerd fest. :D :D

-booOST:cool:
 
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Discussion Starter #16 (Edited)
Storage is just a matter of how big a tank can you fit. For me, I'll only use typical 20lb tanks which give me about 5 gallons. My car isn't a daily driver, and I could have 3-4 of the tanks I swap in/out as I use them, and fill them all at once. Others could run a big 100lb tank and have nearly the same range as they did on gas. I imagine for these people, removing the gas tank and putting the propane tank in it's place would probably be the best idea.

It's funny how people always start talking about explosions with propane. To rupture the tank, you would need to get rear ended by someone going about 60MPH. Propane cylinders are DOT approved, they are pretty tough. They are all over the road in trucks, RVs, and AFVs. Tens of thousands of them out there right now.

I won't use a single injector, rather a proportional flow control valve. Continual injection, no pulses. Makes for ideal distribution when sprayed into the intake stream right before the TB. The level of control in these valves is amazing, from .1% to 100% of flow, in as small as .1% increments. I should stress that the whole system loses practicality if these valves didn't exist. Before I learned of them and how they operate, the whole propane idea didn't fare too well, there was no other way to regulate the flow that would work well. They are a pretty new invention as it turns out. But I'm not the first to consider their use to regulate propane flow. The list of applications includes AFVs.

Trying to keep the propane as a liquid is the biggest headache. I won't discuss all the ways that it can have problems, but they are numerous. Vapor is FAR more forgiving, and simpler. Problem has been, that as a vapor you need a much larger flow orifice to get the same mass flow. A 160lb/hr injector won't flow but 20lb/hr of propane vapor. However the valves I am considering come in some very high flow rates, that would be able to meter all the propane as vapor.

Because of propane's low latent heat of vaporization, you will only get a -12F change in temperature of the air charge at a stoich mixture by having the propane injected as liquid. Not much, and not worth the headaches of liquid injection.
 

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Thats a great idea Derek. However, if you can keep the propane in liquid form up to the nozzle/injector, you don't have to inject nearly as much due to the great expansion rate of propane when it changes from a liquid to a vapor. Also, Viper guys have run propane with nitrous for years now. They don't have any rpoblems having the tanks in the car. You also, don't have to jet nearly as rich on the fuel side as you do with gas due to the characteristics of propane. Derek is correct, it is much cleaner. I have seen some propane only engines (mainly Big block chevy truck engines) with over 100K on them and they are spotless inside. Just my experiance. I do have one very important question though, what if you need more than 104 octane. say like a like single and 30+PSI. Drew
 
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Discussion Starter #18 (Edited)
OK, let me explain the problem with trying to keep propane as liquid.

First off, you can't regulate the pressure. You must keep the pressure at the tank pressure. Lowering it with a regulator will boil the propane instantly. Since propane pressure varies greatly with temperature, you have to precisely monitor the tank temperature.

You need a special type of propane cylinder that draws from the bottom of the tank. These cost $100-$300. Using vapor means you can use standard 20lb cylinders. Just saw them for sale at Costco for $20.

If there is any amount of heat gain in the line after the tank, there will be some boiling, which means bubbles. When the bubbles reach the flow valve, the mass flow rate will drop 10x. It will go lean. Big risk of this.

That's the problem with trying to keep propane as a liquid. It's so easy for it to turn to a gas, and anytime it does, you go lean.

Also, it's very hard to get steady flow through any type of control valve with liquid. It will boil as the pressure drops when it passes through the orifice. The exact point in the valve it boils will vary with the amount of mass flow delivered, and where it boils will have a huge effect on the flow rate. It would probably be pretty erratic.

The jetting you mentioned is more a matter of pressure than the nature of the fuel. Propane is pretty close to gasoline pound for pound, but the pressure it's under is usually 2-4x as much as gas. I have a very nice pressure drop and flow calculator, so I can figure out the flow for just about any nozzle, valve, with any fuel (gas, methanol, propane), at any state (gas or liquid), any temperature, and any pressure. Basically, I can figure out exactly how much flow a given valve will give, without needing to do ton's of trial and error.

As for 30psi, I'd bet propane would do even that. If not, you can always run it with methanol injection. ;)

I got a price on the valves, not cheap, but within reason. Still waiting to hear back from AEM about the inquiry as to if they can add a option to have a fixed frequency PWM output for the injector drivers. The valves require a 250hz signal, with duty cycle controlling the flow.
 

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AnArKey said:
It's funny how people always start talking about explosions with propane. To rupture the tank, you would need to get rear ended by someone going about 60MPH. Propane cylinders are DOT approved, they are pretty tough. They are all over the road in trucks, RVs, and AFVs. Tens of thousands of them out there right now.
Apparently you've never been rear ended by someone doing 60mph. I've been struck in a few collisions with MPH differences similar and siginificantly higher. Obviously I lived, but I also didn't have a 20# propane canister helping to absorb the impact. That wouldn't be "funny". I saw an impact of this nature a few times a week while in fire services as well so it's not a rarity. Chances are it might not happen to you, but you never know. The DOT approval is for use outside the vehicle and none of the vehicles you stated have a canister inside the driver's cabin. Now I'm not granny picking on you at all (those guys bug me too), but you just made it seem 100% safe - and silly to question otherwise. I understand your words because stating otherwise would be bad if you sold this product which you said you'd like to. With that being said, I know the risks and if the potential gain was high enough, I'd risk it. Of course I'm borderline crazy.

Derek, I can't wait to hear about your nitromethane injection kit you're going to tell us about next month. Lately you've turned the Technical forum into the Sci-Fi channel. Good reading none the less mate. :bigthumb:

John "saving up for M50 kit" H
 
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Discussion Starter #20
I never suggested nitromethane injection. Never. That would be a bad idea. METHANOL injection is currently running on many cars and working great.

The steam idea was just a discussion along "maybe" lines. I was hoping for any feedback as to something I may have missed, which I found myself after ahwile, and posted the idea was effectively dead. Still was nice to get people thinking about these things.

The manifold discussion is still very valid, I hope to demonstate some of those priciples with the manifold I'm building.

On propane, I guess I see your point...."something bad can happen." Correct. How is this any different than gasoline? Pretty sure if you get rear ended by someone doing more than 60MPH faster than you, it would rupture your gas tank, and probably cause a bad fire. Any fuel by definition can burn when you don't want it to. How is propane so much more dangerous than gasoline?
 
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