Help with LPG convertor!

[Strick-9]

I need some help from someone with some experience with a liquid propane system.



I've built 4 different vapor propane systems so I'm not starting from scratch.



I got tired of the inconsistency of the vapor systems and decided to go the liquid route.



I need to know what size line others are running from the convertor to the intake.



Apparently, I don't have enough intake vaccuum to open the convertor. I built an adjustable bracket to push the manual override button on the convertor, but then I lose the ability to run more propane with more boost. I'm stuck at a constant level.

I either get detonation at low rpms or weak high rpm performance.



I'm running #4 line to the intake screwed into the clean side of the stock airbox. I'm pulling my filterminder down 1/2 way, so I know there's vaccuum.



My propane powered forklift uses 3/8 line to the intake and that appears to be the only difference from my setup.



I'm guessing that the line is too small to flow the propane while maintaining enough vaccuum to keep the convertor open.



I thought I would ask the experts before drilling into my airbox anymore.



Thanks

Chris

 

[Strick-9]

To update things.



My intake line to the airbox was 1/4" hose with a 1/8" pipe thread going into to the box.



I replaced that with 3/4" heater hose and a 1/2" pipe thread going into the box.



That did it. I actually have WAY too much propane. I'm seeing 8-10 psi boost increase when switched on. Anything over about 25 psi boost and I can hear some detonation.



Now I just have to install an adjustable valve on the intake line and I'll be all set.



Maybe this will help someone in the future.

 

[Don M]

Where is Willis?

I would like to see the propane set-up and maybe take a ride sometime.



I have Ford friends that use propane... . so far I have been scared to try iy out because of the head gasket problems that seem to happen to the Cummins. Probably has to do with overall compression and boost on the Cummins vs. the Ford.



How does the propane work on yours? How long have you been using it?



Don~

 

[MY6EATSV8'S]

I have -8 on an model J and a 0880 aircleaner. Works to around 80hp. For the 100+ mode you can use a -10.

 

[Strick-9]

Thanks Adam. That one line response was a LOT more helpful than it looks. I have some very high flow adjustable valves, but none flow quite as good as straight 3/4" hose of course.



I knew the liquid systems were adjustable, but I didn't know how.

I found out that -12 was too big and -4 was too small, but I thought there was more to it than just finding the right sized line.



My high flow 3/4" adjustable valve is only netting me about 30 horsepower or so. I can just barely feel it come on.



You saved me a lot of time swapping out hose and bushings to find the right size.



Thank you,

Chris