We're cooking with gas!!

[Bluebottle]

As of today both our main cars, a Quantum H4 and a 2002 Toyota Previa, are duel-fuel- LPG and petrol. The Quantum was finished today and has a 55 litre tank in the boot and the bus was done last week with a 60 litre tank underneath the back end where the spare wheel normally goes. We've already done 400 miles in the Previa and so far have been most impressed with the conversion. Startin the engine is always done with petrol and the switch over to LPG happens automaticaly when it reaches the right temperature, usually only a few seconds after startup, more in colder weather. There seems to be a slight loss of torque but it is only very slight.
We reckon it'll pay for itself in about 2 years and, because we keep our cars for many years, we're going to save much more than we spent on the conversions (Until the Chancelor decides to tax the stuff the same as petrol!). Although it's still using fossil fuel the exhaust is very clean.
Anyone else running LPG cars?

[R59]

Yep. 3.0 Vaux Omega MV6 Estate.

A few factoids..

LPG has an octane rating of just over 100.
To make best use of it, you'd need a higher compression ratio and more advance on your ignition (most LPG kits don't do much with the timing, hence losing a little power running at std settings).

Mine paid for itself in just over a year. I only do about 10K a year, but my conversion was pretty cheap (about 1400 for a six injector system).

You'll notice the oil runs cleaner - less soot in the oil = longer oil life.

[Sharky]

I'm going to ask a very stupid question but....

Over here the highest octane petrol is rated at just 93 (probably a bit more since it's now mixed with ethanol). That would mean that high compression cars (compression ratio above 11:1) such as the BMW M5 or the Audi RS4 wouldn't run very smoothly over here. Does that mean that these cars would run better on LPG?

BTW. Most of the cabs here have already been converted to LPG. A cab driver once explained me that he was saving a bundle. However, he did a little demonstration and when going uphill there was significant power loss with LPG. With full load and a steep climb he had to switch back to petrol.

[Pistonbroke]

A few years ago at North Weald I did a test day with Vauxhall Vectras, one of which was a dual fuel car. Under all conditions (full acceleration, light throttle running, high revs, low revs) I could detect no difference, even when switching fuels manually in the middle of the procedure. Perhaps proper instrumentation might have detected a difference but certainly not subjectively by the driver.
Later borrowed for a week an Omega 2 litre duel fuel estate. Sadly underpowered on either fuel, engine just too small for the body, but biggest disappoitment was the placement of the LPG tank. Instead of a doughnut tank in the spare wheel well, they'd fitted a housing the size & shape of a dog kennel in the luggace space - thereby removing the one reason for having a big estate car!
LPG is great - until too many people wise up and that robbing b*****d Gordon Brown realises how much tax he's foregoing & increases the duty on it till it has no economic advantages.