DiezelSmoke

JUST SO EVERYONE UNDERSTANDS LP GAS IS VERY DANGEROUS AND EXPLOSIVE AND DOING THIS TO YOUR ENGINE WILL VOID EVERY WARRANTY BY A MANUFACTURE AND I AM NOT LIABLE FOR ANYTHING.
I have gotten a quite a few PM’s wanting to know how to do this mod., after my posting on this thread: https://www.dieseltruckresource.com/...d.php?t=196002 what seems to attract people’s attention is the fact you can do it so cheaply. If you look around you can find stuff cheap, as always if you want it now you’re going to pay $$$, but the basic system is cheap and with any luck for around $100.00 or less. These were the parts I found feel free to use similar parts especially the hyd valve, these are very expensive normally and I felt very lucky to buy for the price I did. I added a relay to the 12v side so I could shut it off anytime I wanted to, I run my radio in the driveway whenever I am outside and don’t want to power the Neway valve.
I have had it on my 2007 5.9 truck for 10,000 miles and have not had a problem. This is not to say I won’t but I have refrained myself from really cranking up the pressure. If you can retard the timing you could add more LP, but until I can find a reliable way to do this I will leave settings as is. I gain about 4mpg with this set-up , but after adding the amount of LP to each hand calculate mpg it nets out to about 2mpg increase. LP will add HP and a lot of it if not used properly, the truck pullers use it and using it in large quantities will destroy your motor. I have a truck pulling friend and he used it heavy on a daily basis and melted pistons, actually the pistons were destroyed from pre-ignition. I did warn him and am warning anyone here the same thing will happen if not used at the recommended settings.
Basically the system has 4 components: 1) Pilot operated hydraulic valve. 2) 12v Air Neway valve (we use them to operated hyd valve systems remotely) 3) Adjustable LP gas pressure valve(found on deep fryers, big camper stoves, etc.) 4) Brass fitting w/.040 orifice(melted solder inside and drilled hole)
The pilot operated Hydraulic valve I found on EBay, bought a box full of them for $35.00, came to like $8.00 a piece, the one I have is an SMC brand, part# NV8A3135-04N, the pilot is 10-12 psi factory, I had to grind the spring so I had 3-5 psi that is where I wanted the valve to release. A hydraulic valve works well, the moveable steel piston is lubed from the LP gas as the gas will leave an oil film. I don’t quite understand the refining process of LP except it uses oil in the refining process and this is the product left from that.
I used the standard air Neway valve, it was available to me and you can purchase these on EBay for about $20.00, you probably should use an electric valve like the ones used on forklifts, they are spendy and are probably safer. If you use the skinner valve you will need to block the exhaust port, now I thought this would lock up the valve and prevent it from shutting off, but seems to work.
I bought an adjustable replacement LP valve from Menards……… Wal-Mart, Home depot Lowes, etc. have the same thing, they are $18.00. It appears the one on your grill will probably work just fine, the pressure we want is about 7psi and that is what a standard grill uses, for a pickup it is fine for a semi you would want an adjustable one for greater flow.
The brass fitting going into the intake side of the turbo is just a brass fitting and use whatever fitting you want and I just filled it w/solder and drilled a .040” hole through it, this is important as it is the metering system for the amount of LP getting into the engine. A couple dollars for this from any auto parts store, hardware store, etc.
Installation: I use a standard 20lb LP grill tank for the fuel supply and mounted it in the left rear corner of the truck box. I used a ratchet strap to secure the tank to the box using the tie-down spot in the corner. I ran wire and copper tubing from the front under the hood of the truck to the rear were the tank is mounted. The Neway valve is mounted to the tank and adjustable LP valve is mounted to the Neway valve. I hooked the 12v wire to key power and copper tubing to LP valve. I mounted the hyd valve in the engine compartment on the firewall and ran the plumbing to the engine as pictured.
I am sure I missed somthing feel free to ask any questions.

eldgenb

great write up!! There were some serious trolls on your last post lets hope they stay away.

edtyler

Thanks for posting this. I am guessing that the clear plastic tube from the air horn to the bottom port on the gas valve meters the gas being delivered to the input side of the turbo.

Is this a progressive flow or does it come on full bore when the air horn reaches the set point (which you lowered from 10 psi to 3-5 psi)?

Also, how well does this improve efficiency around town? I can see where it would be very good on the highway where the flow rate could be calibrated for a given power level.

DiezelSmoke

Let me explain the pilot operation of the hydraulic valve better than in my original post. The normal hydraulic valve that everyone thinks about, operates by your hand on a lever, the movement of the handle moves the spool inside the valve. The more movement of the handle/spool, the more fluid is allowed through the valve, the more work being done. Pilot operated means the movement of the spool inside the valve is moved remotely, in this case turbo boost pressure. The plastic line going to the bottom of the valve has turbo boost pressure and this operates the pilot portion of the valve.......so the more boost pressure the more the valve moves the more gas is delivered to the motor. This is especially helpful with in town driving as well as highway when turbo boost pressures are highest. The valve is set to deliver LP at 3+ psi turbo boost since we want none at idle. Hope this clears it up some.

From what I have been able to find info on, the store bought'n/high buck units, I am at the same delivery rate as them. I think this can be improved, I just have not found a way yet to confirm this isn't going to harm the engine.

AlCorr

Excellent write up, I've always been interested in adding LP gas to mine but have had no idea where to start. Do you know of any good systems I could buy?