i'm bit confused on how you meter the gas. Are the nipples you added to the carburetor open hoses or are they for metering. YOu don't have a throttle position sensor? what is picture http://home.hccnet.nl/e.pilage/images/Dscn1514.jpg? Any companies that sell that sort of thing have good web sites?
One comment on the horsepower for those interested, LP is close to propane which is 106 octane. If you want horsepower you have to loose the ability to to run pump gasoline and run 11:1 or higher compression. From what i've been reading it seems going up 1 point in the compression ratio gives back what is lost by the slower flame speed fuel.
On the subject of clean burning. LP burns so clean that in australia they sometimes add a real small oil injector, i guess to put a bit of carbon in the system.
I've been looking at going CNG over here but i plan to go with a late model restomod setup.
On the CNG subject, I'm in the process of buying a 2000 CNG Crown Victoria. Only 175hp vs 220hp for the gas version, but running CNG will get me into the commuter lane here in CA... That should cut +30min from my daily commute during the summer, +45min in the winter.
CNG burns more than 90% cleaner than gasoline. It has less energy than gas, but because the octane is 120, they increased the compression to compensate.
For those of you who want more info on LPG/natural gas systems look here Gas research. LPG is used quite often in Australia as it is less than 1/2 the cost of Petrol for the same volume/milage (~0.20USD per liter for LPG vs ~0.45USD per liter for petrol). If the gas system is done properly, you should loose no more than 5% power in the case of dual plane intakes, and you can actually gain power if you use a single plane intake on a stocker motor (LPG is a gas at RTP, thus there it doesnt condense at low velocities like petrol does in single plane intakes). Additionally, LPG available in Australia has an octane rating *minimum* of 110 - this means you can run very advanced timing, high compression, high boost (for blown/turbo applications) without fear of detonation. In australia there is a variety of LPG equipment available from in air filter supplies (for dual fuel applications) to complete gas carbs and EFI systems.
australia is very different than the USA. Propane is sold here pre-bottled for things like grills. There are very few gas stations that still fill them. for CNG you can either compress it yourself or at least in this part of the country you would need to go to a bottled gas (welding suply) place to fill a cng auto.
There are three CNG refueling stations between home and work, 30miles. Not exactly "one on every corner", but the closest station is about 5 minutes from my house, actually on an onramp to the freeway I commute on.
To qualify for the HOV lane with a single occupant in CA, it must meet the requirements of ULEV AND ILEV. The ULEV requirement isn't difficult to achieve with gasoline, but the ILEV requirement ONLY allows electric, CNG, and LPG fuels. A dual fuel vehicle using gasoline would not qualify. Here is a CARB website with some qualifying vehicles. One interesting vehicle included in the HOV exemption is the 5.4L CNG F-150. I see these driven by CalTrans sometimes. If someone would make a hybrid that ran on a CNG or LPG engine instead of gasoline, it would qualify for HOV.
Additionally, a company called FuelMaker makes a refueling station that can be residentially installed. I've heard they run about $4k, but they're trying to get the price down to $1k. Essentially, the natural gas is used to fuel my furnace and water heater here in CA. This refueling station will compress about one tank per day. So just plug it in at night and it refuels. Or maybe an employer could be convinced to install one and get a tax credit. Supposedly they're about as noisy as a pool pump, so if you have neighbors, an enclosure might be in order.
The picture you are refering to is the fuel cut off switch. When I switch over to LPG while driving I put the switch in the middle position till all the fuel in the carb is used, then I switch to LPG. When switching back to fuel I put the switch immediatly back. It then takes a few seconds before the carb is filled with fuel so the engine dies for that few seconds.
There are no metering devices on the carb. These pipes you see are just open pipes!
There is a big membrane in the evaporator. This membrane measures engine vacuum and controls the LPG flow.
There are also 2 cut off solenoids for safety reasons and 1 solenoid to inject some LPG in the carb just before starting the car.
My 72 LTD was setup to run on LPG. I had a meter unit that mounted on the carb, and a regulater that was on the fender. I have been pulling it all out, so if anyone is looking for anyparts for one, just drop me an e-mail. One problem with the LPG is you get very little lube for the valve seats. The heads on the motor were wiped at 70k. Seats are almost gone.