Competition Someone give me a quick education on the pros/cons of propane

[2broke2smoke]

good friend called and asked "why don't we try propane?"



truck is an '03 305, tst box with the twins program and rail pressure upgrade, sps 64, afe intake and straight exhaust ...



so ... what's the good, bad and ugly?

 

[boydo]

Pros = better milage, and solid torque increase on mild tuned trucks.



Cons = I takes a whole day to re and re the head gasket on highly tuned trucks.





I ran lpg for towing lots with great succuss aroung the 450 hp mark, know I'm removing the system, it adds great power still, but I'm always doing Head gaskets with the mods I have now ( 700 hp). I 'll stick with H2O/Meth or try a little gas before I'll risk the weekend to lpg.

 

[JasonCzerak]

Pros = better milage, and solid torque increase on mild tuned trucks.



Cons = I takes a whole day to re and re the head gasket on highly tuned trucks.





I ran lpg for towing lots with great succuss aroung the 450 hp mark, know I'm removing the system, it adds great power still, but I'm always doing Head gaskets with the mods I have now ( 700 hp). I 'll stick with H2O/Meth or try a little gas before I'll risk the weekend to lpg.

why is propane breaking your head gasket? it is messing with the timing with real fuel to early in the cycle?

 

[CanadianCarGuy]

Propane will make a diesel detonate if the timing is too advanced and there is too much propane being burned. If you get a propane kit make sure you get the one with digital engine parameter sensors, so it will stop the propane injection when there is risk of engine damage. I would definately get meth/water injection before propane.

 

[AKaiser]

Some good info (I think) about proper LPG setup and what it does and does not do. LPG (Propane) Fumigation for Diesel Engines

 

[boydo]

The lpg system I have rules, digital controller that is totally tunable, the system is from EEE TEE digital designs, I have just found that once you go over the 500 hp mark things get risky. Propane when mixed with the air going into the combustion camber at the RIGHT mixture makes timing very precise do to the increased burn rate, this make great torque, but in doing so makes very high cylinder pressures. I guess what I'm trying to say is if your into big power propane is not for you, if you want great milage and a solid 20 % increase in torque on a lightly moded truck you love it.

 

[TAbbott]

I've had propane injection on my big rig for over 600,000 miles with no problems. It works great, as long as it's used in moderation. The key to using propane is not to use too much of it. The old adage "if a little is good, more is better" doesn't apply to propane in a diesel. You should never dump enough propane into the engine that it is capable of burning by itself. You always want the air propane mix to be less than that that is capable of supporting combustion on its own.



The fuel/air ratio shouldn't be over about 2. 5% -- 3% propane vapor by volume, as 5% propane by volume will burn by itself once it is "started" by even the idle injection volume of diesel. This creates an uncontrolled flame front that bounces around inside the cylinder colliding with the flame front from the diesel injection. If the diesel injection event is large, this creates pressure spikes that damage the engine. At 2. 5% or so, the only portion of the mix that can burn is that which is in direct contact with the diesel flame front and the timing is thus controlled by the diesel injection event. A singular flame front is produced -- no pressure spikes, just much improved drivability and power.



Another interesting fact is that no matter how much propane you inject into the engine, it can never be ignited by the heat from the diesel compression stroke alone. It requires an external ignition source to get it going, which is why it works really well when in the proper ratio, as it requires the diesel flame front to get it going, and the timing is controlled. Otherwise you'd need a spark event like in a true dual fuel engine. Propane's problem is it burns at a different rate than does the diesel when the mix is rich enough for the combusion to support itself.

 

[AKaiser]

The lpg system I have rules, digital controller that is totally tunable, the system is from EEE TEE digital designs, I have just found that once you go over the 500 hp mark things get risky. Propane when mixed with the air going into the combustion camber at the RIGHT mixture makes timing very precise do to the increased burn rate, this make great torque, but in doing so makes very high cylinder pressures. I guess what I'm trying to say is if your into big power propane is not for you, if you want great milage and a solid 20 % increase in torque on a lightly moded truck you love it.

Has anyone been able to find the "sweet spot" with regard to fuel economy where the amount of LPG introduced into the mixture gives the lowest total cost of fuel used? Mr. Sharkey seems to think there's a point where you're using just enough LP to create a more complete combustion of the diesel. His figures were going from 75% straight diesel up to 85-90% with LP added. Is that percentage correspondent to a decrease in total fuel cost?

 

[WUnderwood]

propane is also addictive, if you try a little bit, and see the performance, the chance to turn it up is always there, and hard to refuse.

I would try water meth, because I think it is a little easier on the headgasket, and less cylinder pressure

just my opinion

 

[2broke2smoke]

thanks guys ... very good info