LPG MPG for 4.6is

[iimms]

Has anyone got a 4.6is converted to LPG?

I have just had mine fitted with a BRC kit with twin Vapourisers. I also had a shallow battery fitted so I could get a 95ltr tank in.

I would like to know what mileage others are seeing from LPG

I pay 69.9p/l and have filled up twice, costing £50 and £52 which the later was 74.4 litres (i know they only fill about 80% because its gas). I managed 220 first tank and 250 miles second tank.

This was all motorway cruising 70 - 80. The computer had trouble getting past 19mpg - whereas on petrol i could get it to show nearly 24. (I was told to expect 2mpg loss on gas).

However if you do the maths it seems its only managed 15-16 mpg! I expected at least 300 miles from my large tank.

Can anyone else indicate what they get on LPG please? Not tried it round town yet, and its only done these 500 miles since conversion, has to go back at 1000 miles for check up but cant see that making much difference?

All help really appreciated - shelled out 2100 on this!!

[Icer006]

LPG for a 4.8is? WHY?????

[iimms]

No, 4.6?

Why not? confused? lol

[TriX5]

Can't say I have driven an LPG car in a long while but I seem to recall the loss is 15 - 20% simply because the energy density is lower. I.e there is less energy in a liter of LPG than in petrol. Nothing to do with the engine or the vaporizer really.

How much a petrol per liter in your neck of the woods?

[iimms]

in the south east, 119.9 unleaded, 123.9 diesel, 69.9LPG

[TriX5]

Ouch, that over $5/gallon. No wonder LPG is attractive. Post some pictures of how they did the install if you can?

Not that we will see LPG here anytime soon tho CNG seems to gain in popularity soemwhat.

[JCL]

Originally Posted by TriX5

Can't say I have driven an LPG car in a long while but I seem to recall the loss is 15 - 20% simply because the energy density is lower. I.e there is less energy in a liter of LPG than in petrol. Nothing to do with the engine or the vaporizer really.

Less energy means you use more of it, it doesn't reduce the power. The octane rating is up around 110, so with a properly designed kit a driver shouldn't notice any appreciable power loss.

[TriX5]

Agree - I did not express that quite right, good kits do indeed limit the power loss. My last LPG car was a '75 2002 which I traded in 1983...... I drove a couple of 320i from the mid 80s (thanksfully not mine) that were absolutely horrible and seemed to loose over 25%.

I drove some VW lease cars from the mid 90s which were much better but I have not driven one of the later kits which are supposed to be better then ~94% (?).

iimms, any idea how the 4.6 does in terms of power on LPG?

[iimms]

In terms of power, if you weren't told it was LPG you wouldn't know, still goes like a rocket and can tell no difference. Some kits are marketed as having a feature whereby they switch back to Petrol when you drive it hard - that just means they are cheap kits not up to the job. The changeover from petrol to LPG once warmed up is seemless, and cleverly changes 4 banks at a time instead of all 8, to keep changeover smooth as possible.

TriX5 - didn't realise you were from over the water, now I get why you said 'WHY???' !

With 4.55litres to an imperial gallon, a gallon costs us £5.46

To you that would be about $10 a gallon!

Send me some petrol you lucky sods!! lol

[TriX5]

iimms - It was our SoCal member Icer who asked "why?" I was born at your end of the fishing pond (NL) and I understand the need to save some pennies on fuel :-) I even spent 3 years in the UK in the early 90s, wouldn't mind repeating that!

Interesting to hear that the kit works well and is programmed to "ease over from LPG to petrol" and vv bank by bank.

I will be buying and burning some of that expensive fuel myself in two weeks when I go home for X-mas. Good luck with your convert!