Alternative Fuels

You also should use an electric lockoff. The VFF30 is vacuum operated. As soon as you begin generating boost it will cause the vff to close. Secondly you may find the 425 too large for your set up. Since you want to be dual fuel consider a 300 or 300-50 mixer.

Right on sleepy. J is only good for about 100 HP. The E and L are good for about 300 to 350 HP but the E has better heat transfer then the L in cold weather and when really long periods of hauling are required. Go with the E whenever possible.

On over the road applications its best to overcarburate a little. Twin CA100 mixers would probably work well. Another serious consideration is the CT60. This is a new mixer IMPCO made to work with most of its convertor applications. By the way the 50 series is now a 55 series. Same mixer with some i...

Onan also used another method, They routed part of the exhaust gases through model J regs for their generators. To do this they inserted a stainless steel sleeve into the water passage to protect the reg. IMPCO used to sell a special kit for this, however I don't think they supply it anymore. Once i...

You are correct about the holes transferring vacuum to top of the diaphragm. This vacuum is generated by the air flow through the mixer. Drilling them would cause the gas valve to lift quicker. Unfortunately it will also cause your mixtures to be very rich at part throttle and cause excessive fuel c...

Two of the best ways are to use an IMPCO SV (start assist valve) or VPV (vacuum power valve). The start assist valve is installed in the secondary side of the reg (a port is already there on model E regs) and a 1/4 inch hose is routed to a fitting in the base of the mixer. This is an electric operat...

These are typically leased from the local NG supplier. They provide and install them according to code. At some time the unit Will need overhauling. The company supplying it will perform the overhaul at a price or it may be built into the cost of the gas.

That looks more like it goes into the vapour side of the reg. I suspect it is a temp sensor as Franz suggested, but it likely monitored vapour temp. This probably was connected to a box that controlled water flow through the reg to minimize sludge formation. Companies like Technocarb and ECO used to...

Keep in mind that prior to computerized timing manufacturers had to be very conservative with timing. Gasoline octane could vary substantially so they set timing based on the potential lowest octane they might encounter. LPG timing was also set based on a conservative number set for an octane rating...

Lead was actually used to increase the octane of gasoline to prevent pre-ignition. A side benefit was the lubricating quality allowing the use of softer material on the valves and valve seats. Unleaded gasoline forced the man. to use hardened valves and seats. An engine rated for leaded gasoline wil...

Not quite true. IMPCO systems add fuel based on airflow, not altitude, so they are self compensating in most conditions. If a vehicle had a very small engine or was pulling a heavy trailer all the time at max RPM and power altitude, might affect full load mixtures. This can be compensated for quite ...

The GM computer automatically goes for the most aggressive curve. The knock sensor will retard the timing if it feels any ignition knocking. Since propane has a lot higher octane then gas the timing Will advance further on LPG and less on gas. Nicest part about the GM EFI is the aggressive timing cu...

Yep, that's the screw. It likely is not at its factory setting now anyways. Also its there to adjust for various sized engines. Later feedback versions did not have this screw. The other mixture screw is for idle only. For timing check out the post addressing ignition curves. Frank gives a pretty go...

In addition to Frans comments early 450 mixers had a manual power adjustment screw where the vapour enters the mixer. This screw was used to adjust the power on a dyno. If you don't have a dyno use a lonely stretch of hwy. Do some acceleration runs between two fixed points. Telephone poles usually w...

You say all the computer controls are gone so you don't need a computer controlled LPG system either. If memory serves me the MC2100 is a two barrel carb??? If so you can either replace the complete carb with a throttle body and mixer for LPG or if you want to go dual fuel you can put an IMPCO 300 o...