Thread: New to LPG - feel it should be better?

18-20 l/100 consumption sounds about right.

Bee-utey is the best person to help with tuning.

You can expect 20% more fuel consumption on gas - the savings are in the purchase price of gas over petrol and not in its on road consumption.

Garry

The legally mandated maximum fill level of an automotive LPG tank is 80% so your tank should hold around 65 litres from empty. It could be less becuse of errors are only allowed in the underfilling direction. Now you should get used to running right out of gas, the power drops away over a couple of km as the final tank pressure drops. (You may also hear a whistling noise from the tank) This gives you plenty of time to change back to petrol unless you have just hit a steep hill. Then check the fill amount.

Now as for tuning, you should be running more ignition timing on gas than stock, depending on your compression ratio you can run up to 12 degrees advance at idle. If it pings on petrol, run a bit of premium juice in the tank.

Your spark plugs need to be slightly different too, choose plugs one heat range colder than stock, and gap them to 0.7mm.

Finally identify your main gas flow adjuster, tweak it down bit by bit until you lose power, open it again until you have full power but no more. Most common lpg systems will run richer with a dirty air cleaner element so make sure you check the power adjustment after an element change, and anytime your economy drops drastically.

But yeah, gas is no longer the ultra cheap fuel it was 20+ years ago, so expect around 40% saving if well tuned, less if not. Personally as a gas fitter I'd be embarrassed putting such a small gas tank in a V8 truck, 70-80 litres would be better.

Originally Posted by garrycol

You can expect 20% less fuel consumption on gas - the savings are in the purchase price of gas over petrol and not in its on road consumption.

Garry

You mean more, the price off sets the consumption. I use to get 5klm/l in my 2dr 4 spd rangie with a useable 70ltrs out of the twin tanks (350klms), on a good run that would stretch to 420klms - this was with an impco 300a on top of a holley 350, bosch holden dizzy, mild porting but otherwise stock 3.5 .

B-U
Thanks as always for detailed info! That's good to know about running out - ok, I might sound like a tool - but I was concerned about that, in that I expected some kind of mechanically damaging backfire when it breathed its last.
On the occasions I've run on petrol it has pinged a bit so I'll remember to put some 98 RON in it, but until I can check I assume it's maybe timed for gas.
I'll change the air filter and check the plugs - when I can get through the plumber's nightmare

Got in to leave work tonight and the red bar on the gauge - odo reading 272kms. Drove with the green/red flashing for about 30kms before I stopped to put some in. Hmmm, filling every 2 days isn't filling me with joy - might be better off driving the Td5 to work after all
Cheers
Mike

Originally Posted by loanrangie

You mean more,

Yep - thanks - edited my post.

Cheers

Garry

20% for mixer. Basically line ball for injected. I really love paying 62.9 cents per litre. My D2 with roof racks, bar etc is like a 4cyl camry to run on petrol. and more torque than on petrol too

Cheers