hey sorry to break up the party but ive been told by a gas fitter that it is not recommended that to run lpg on vn v6 t5 coz its something to do with the ecu that they dont like it and they backfire like crazy he said he once fitted one and it blew a HEADLIGHT!!!! not sure if this is true or not u stil having problems??? coz if not i wouldnt mind running mine on lpg.. also what sort of kms do u get from a normal tank??
I've had LPG on my '91 series 2 vn v6 with the 5 speed for about 4 years now. It ran great for 6 months.... then it started with the backfiring. The next 2 years i just learned to live with it. Changed the plugs multiple times, 2 sets of brand new coil packs, new leads, but nothing really helped. It got real touchy and would go BOOM whenever i'd accelerate hard, had to drive it like an old woman, babying it everywhere. I experimented with lots of ways (flaps, plugs, caps, bits of icecream container(bad stuffed happened with that)) to try to get past the whole exploding airbox thing, but the best method on that front was to modify the L-shaped pipe that goes from the throttle body to the airbox. I put a Y-piece of drain pipe in line with that, with one end of the Y going to the airbox, and the other end of the Y with a plastic bag rubber-banded over it. That way when it backfires, it's got the tiny resistance of the plastic bag to blow off, and not the airbox.
Anyway, i eventually found the source of the problem, it WAS as everybody had said all along: poor ignition. The "DFI module" the block that the coils sit down onto had corrosion on the terminals. I cleaned the terminals up and BOOM problem solved!
It does start backfiring again every 6 months or so, so i just unbolt the coil packs, and hit those terminals with a wire brush on the end of my cordless drill, spray some contact cleaner in the coil pack hole things, and put it all back together. It's a 15 minute job that keeps it going again for another 6 months. And my Y-piece of drainpipe, plastic bag and hair-tie(they don't deteriorate like rubber bands) save the airbox when it does inevitably start backfiring again.
It's bogan as, but hey, it's a good conversation piece when you have to pop the bonet ^_^ hahaha
My gas guy told me it wasn't a good idea either, especially considering it had 300 on the clock (425 now), but my whole experience with gas has been good, i would do it again in a heart beat. the amount of money it has saved me ......
Its been years but i remember i used to get 600km to a tank of petrol, 55L when filling up. It was then 520-550 with similar driving on LPG with 57-60 litres or so of LPG going in.
I've got pics of my dodgey setup around somewhere but can't find atm, can take another photo if you're interested
Peace
