propane

old bird

Registered User
I have had lots of experience with propane as sole fuel. I have had no experience with it in conjunction with nitrous. Propane is used as a performance booster in diesels very effectively. Has been done with Ford powerstrokes.

It's biggest advantage is that it is a pressurized gas, that liquifies under about 150# pressure. when it is released to atmospheric pressure, it absorbs almost all of the energy that was required to compress it to a liquid. It absorbs this energy as heat. In other words, if the propane is released as a liquid into the intake air post supercharger, it will cool the mixture down significantly, like nitrous, and provide an additional high octane fuel scorce. It may well provide significant peformance enhancement, with no detrimental effects.

Old Bird.
 
hmm thoughts

My thoughts on shooting propane into a 4 cycle engine NOT setup for it is like pulling the pin on a grenade and handing it to your engine.
Sure Ford made 4.6's to run on propane or CNG to be more precise and there have been conversion kits for pickup trucks out for years but there HAS to be a reason this is not done widely or more often.
Reasons:
1: less power I know you mean to add it like N2O to add power and while it will cool the intake charge theres really no telling what it will do the SC or the engine other than make it run richer than normal. Thus Less power
2: Lousy reliability Propane is VERY fussy (just ask your furnace repairman) it doesn't like to flow in cold weather nor does it like it HOT(it vaporlocks). Like the 3 bears it likes it just right!
3: God help you if you got rearended!
4: Emission test points and your yearly checks
5: See #3
Just my thoughts, if you plan to do this get good insurance and keep it paid up!
 
Dave Neibert installed a propane injection system on his car. Not sure if he ever got any results from it or not. From the research I did it looked pretty promising. I believe the biggest advantage was that it could cool the charge under boost even lower after it had passed through the IC Many moons ago in college I worked on a team that converted a Dodge minivan to run on all propane. It wasn't too bad and the higher octane level of the propane allowed us to run a pretty high (by stock standards anyway) compression ratio. The tank we had was pretty damn heavy though and expensive since we stored it under pressure (liquid injection). I don't think propane is any more dangerous than gasoline in a vehicle.
 
Like Kevin said, I installed a propane injection system on my SC about 3 or 4 months ago.

The idea was to get a cooler intake charge to allow more boost without triggering the knock sensor. I'm using a hobbs pressure switch that came with the kit to activate the solenoid on the tank.
I'm set at 10 pounds of boost, and could go as high as 14 using the same switch. The kit also includes a pressure regulator and a flow control valve.

Setting the correct flow and pressure requires a dyno with a wide band o2. I tried using it on the track and ran slower (to rich), I tried adjusting the flow and pressure on the dyno but with only two pulls there wasn't enough time to figure it out. It lost power both pulls, 40 rwhp and 20 rwhp.

Part of the problem is that my car is dyno tuned with a custom chip to run on 93 pump gas and adding the extra high octane fuel (propane) made it run rich (9:1) and killed the power.

To gain anything from it, I think I'll need a custom chip that leans the fuel out and adds more timing whenever the propane is sprayed. The timing is easy..the fuel thing is not and could potentially be dangerous if I get to lean.

I'm planning to experiment a little more this summer but don't really think I need the propane now that I've changed cams and installed a front mount IC.

Here is a picture of the bottle in the trunk. I made the tank mount bracket from a large fire extinguisher bracket.

propanetank2.jpg


This picture shows the pressure switch and the injection nozzel with the yellow ring on the fitting.

nozzell&pressure.jpg


David
 
David-
I am starting to understand a little more how this system works. One question though. Can you progressively control the propane flow, or once it is set, it is set. Just wondering if at 10 PSI, the propane flows X amount, but does that amount stay consistent? or does it propane(X) + boost(Z) = flow(F)
 
TBS Coupe,

No it isn't a variable flow system. Unfortunatly while the pressure and flow settings are fully adjustable, it is a fixed volume once you start spraying.

So at lower rpms it is spraying the same amount of propane as it is at higher rpms. In theory, the higher your rpms are (flowing more air) the lower the percentage of propane will be. So you end up with a fuel curve that is gradually getting leaner as rpms are increased, this is what makes tuning the fuel to work with propane so difficult.

Since I'm curently tuned to 12.5:1-13.0:1 AF ratio, any additional fuel causes a rich condition resulting in a loss of power. My timimg is already advanced to 28 degrees at WOT without detionation, any additional timing reduces peak HP but still isn't knocking at 29 degrees.

Im sure the cooling effect of the propane will be needed most during the dog days of summer, so that's when I plan to try using it again. However, I'm curious how it would work with a dry nitrous system for fuel enrichment. With both systems being fixed volume it shouldn't be to hard to get them balanced.

David

I just re-read your post and if your asking if the pressure of the propane increases the boost, no it doesn't. There isn't enough volume flowing to do that. It's only being injected at 80-90 psi, in gas form at about the volume required to run a BBQ pit.

PS: Old Bird, when responding, start by pressing the tab that says "Post Reply" not the one that says "New Thread".
It getting hard to follow all the propane threads. Thanks
 
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In order to make use of propaine injection you would need to have higher boost or run more timing.Otherwise your going to loose power..Try running race gas in a stock car and see what happens..Same principal...Ive used alcohol injection before with great results..Dammed if Im putting a propaine tank in my car..Its all in the timing and boost..As soon as install heads and cam (very soon) im reinstalling my alky injection kit....Well see what happens
 
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