Just wondering if a standard air/fuel meter gauge that wires to the 02 sensor can be used on cars running straight LPG? Is there a difference in readings between petrol and gas?

Yes it will work, though as with petrol, not very accurate. Still, they can give a general idea when doing mods. Some have a switch to change to an LPG setting. Otherwise the reading will be slightly out. No big deal.

taken from fullboost forum: TUNING : (*note* i always tune in lambda, as lambda figures be it for methanol, petrol or lpg are always the same. A/F ratio will differ!! i.e. 1.00 lambda = 14.7 afr petrol = 15.5 afr gas! http://www.gasresearch.com.au/gratus.pdf < this is a fairly good guide as to what you need in order to set your car up right) I have tuned my vl, and it is currently running a bit rich through the entire rev range @ 0.79 lambda, this means that the car does run a little bit hot (too rich or too lean with lpg will mean the car will run hot, not a good thing!). I currently have a 48 size metering rod in there (the metering rods have identification numbers stamped on them, the lower the number the small diameter the rod [richer]), and will be going to a 49 at first to see if i can get to the 0.83 that i am after. Always start rich and lean off! After you have tuned the car for WOT, you can start on the idle and cruise. These are metered via the way of jets put into the vac lines attached to either side of the t/body. The side where the screw with the spring is the idle circuit. Here you want to put the right sized jet in the vac line so that you can adjust the idle fairly easily with the adjusting screw. Screw in to make mixtures richer, out to lean off. I like to have the car a little richer than 1.00 at idle so the car idles nice and steady and doesnt 'hunt'. have a read through the link uptop ther (http://www.gasresearch.com.au/gratus.pdf ) its an awesome guide to tuning the GRA gear and also has an air fuel ratio chart at the bottom, stateing the difrence between gas and petrol a/f ratio and also giving the lambda rating. go sick Some original photos have not been recovered yet.