Is LPG the answer to low mpg/big engined cars in the future?

[MPETT]

I drive an E46 M3 as my every day car (it seemed like a good idea a year ago with fuel at £1.18!). I'll be doing so until my TVR project is finished when I'll sell her for an old banger for commuting in. The TVR will be my fun car for the weekend.

I've been thinking for a while about the cost of fuel and the inevitable rise in its price. LPG systems have come a long way in the last few years with sequential injection and power losses of only 5%. This loss of power would be absolutely fine for me. I drive 60miles a day in my M3 along country roads, and frankly 340bhp is too much to enjoy sensibly, so power loss is not an issue. Of course you can always switch back to petrol at the flick of a switch.

I've heard more and more people who want to use their cars talking about LPG.

What do you think? Have we got to the tipping point? Are our beloved sports cars with large engines going to depreciate due to the cost of fuel, and is LPG the only solution?

[55allgold]

I've thought about LPGing a big-engined car (I'm partial to the old MB 560SEC). But whenever I go browsing for LPG cars, about 50% of the adverts say that the LPG system:

• needs attention
• has just been fixed at £££££s
• has some weird setup thing (not ehen warm, not above/below so many revs, etc)

If I knew more about LPG, I might understand why these matter or not.

Worse still, so many have has the world's ugliest filling cap stuck like a wart on the rear flank.

[MPETT]

From my understanding today....

The system's injectors need to be rated to the engine's size and performance, so if not being enough the system will introduce petrol to the mix when there is a high demand. A good system is specified correctly so that you run on LPG 100% of the time.

The new LPG sequential injectors patch straigth into the car's injection system, so I understand that that fire LPG vapour into the cylendar at the sime time as the petrol's system would. The LPG's ECU the modifies when the spark plug ignites to optimise combustion for LPG.

Having looked around you can fit a new system for an M3 (which should be comparible to most performance engines) for between £1200 to £1700. Based on this cost, it would be cost neutral within 6 months for me based on 60 miles a day for commuting.

So you could always budget buy a large engined car on the cheap (today) because of the fuel prices and use this saving to fit a brand new LPG system!

[DS3R]

The problem with LPG is that the Gov has left the door open to raising the tax discrepancy between it & regular fuels.

So at some point (and they have to give- I think- 3 year's notice to change it) the point of having it stops.

[MPETT]

I know this kind of pisses on the topic, but I found this.... I thought I'd read about a commitment until 2015

http://www.drivelpg.co.uk/the_benefits.php

The low price of LPG autogas is a result of the low level of fuel duty applied by the government. This government support is in recognition of LPG’s environmental benefits 
 
In the 2011 Budget, the Chancellor confirmed a reduction in fuel duty for LPG equivelent to the 1p per litre reduction in duty rates for the main fuels.
 
As regards the differential in duty we have with petrol and diesel, LPG duty had benefitted from a five year commitment on fuel duty as part of the Fuel Duty Escalator. This has been abolished and replaced with a Fair Fuel Stabiliser which allows for duty to rise by RPI only when oil prices are high, but by RPI plus 1ppl when oil price falls below a trigger point.  As part of this policy the Government has signalled its intent with regard to LPG until 1st August 2012 – a continued duty differential reduction as would have happened under the previous policy.
 
Beyond that date there is now no signal on either main fuel duty or its relationship to LPG duty as the Government will be seeking the views of oil and gas companies and motoring groups before setting the final trigger price and mechanism for implementation. UKLPG is in discussion with MP's and government officials for a replacement of the long term commitment for LPG.

[kambites]

In the long run, no. LPG is still a fossil fuel and hence will suffer from the same supply issues as petrol. It's only cheap because it's not taxed as highly.

Makes a lot of sense in the short term, though.

[Bungleaio]

LPG is great, it's made running my Impreza every day at lot more financially viable.