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dom14
24th June 2015, 02:54 PM
Hi guys,
I've found below article which nicely explains the issue of dual fuel as well as special
ignition requirements for LPG.

http://www.acl.com.au/web/acl00056.nsf/0/359683e8a538a3e64a2566c0007bb33e?OpenDocument

Mine is a GQ RB30 carby model on dual fuel.
I drive on LPG most of the time.

So, if I can quote below paragraph from the above article,

["Ignition Switching Devices

The best way to be sure that the ignition is optimised for both fuels is to install an ignition switching device, known also as "Dual Curves". These units are wired into the ignition system and switch automatically to the LPG or petrol setting when the fuel switch is activated. They will give more initial advance than the petrol setting when the engine is running on LPG, and as speed increases they will give less advance than the petrol setting. Although these are usually pre-calibrated for a range of applications (i.e. not necessarily calibrated for a particular engine) they will give a much better approximation to the ignition requirements for engines being converted than the incorrect practice of merely altering the static timing."

Where can I get hold of those Dual curve units?

I'm particularly interested in a dual curve ignition unit that can adjust the ignition curve for LPG. By that I meant,if I follow the above article, more advance initially on low engine speed and less advance as the engine speed increases.

Thanks

dom14
26th June 2015, 12:08 AM
These are the ignition control units I've come across while ago.
Not sure whether they do the above(dual curve), but definitely auto adjust the timing for LPG/petrol vehicles.


http://www.aeb.it/Products/Products/CatID/8/Timing_advance_processors

These guys are the distributors in Australia.

http://www.sprintgas.com.au/home_page.html

Last time I checked with them(2013) it was quoted around $120 for one of the units for dual fuel.

dom14
26th June 2015, 12:17 AM
I'm not sure above units work as "dual curve" units.

There are few listed.
I'm wondering whether a dual curve unit must be accompanied with an RPM sensor that connects to the dual curve unit to sense the engine.
Or does it simply pick the running rpm from the coil?