Did a reasonable trip at the weekend (Watford, Harry Potter!) and running around to and from work and then topped up this morning. About 200 miles for 42l, which is 20ish a gallon.
Petrol is £1.35 for non supermarket round here for unleaded. £0.72 for LPG, so that's about half, so ~38-40 MPG price equivalent!!!
However, I've a Flogas outlet on the industrial centre in Peteborough who have an LPG pump and it's £0.52 a litre!!!
That makes it over 50MPG equivalent
It also produces less emissions, burning cleaner and hotter.
Driving generally isn't effected, normal stuff you wouldn't know. Starts up for a mile or so on Petrol to warm up the engine but then the change over is hardly noticeable. Normal cruising is the same, decent acceleration is nice and vroomy.
*REALLY* booting it and it beeps and drops back to petrol but there doesn't seem to be a noticeable lag like my old Prins system. We're talking major kick down here and once at rocket speeds a press of the button and you are back on LPG anyway!
It is a bit of messing around, particularly with a european adapter type filler which is frowned upon, but I do like a big 4.2 V8 mega spec comfy sporty car that is also cheap to run (£260 tax too, being an '05)
Lee