LPG - Desirable or not?

[dsearle]

Guys,

I'm stunned at the partex value of our cars. I've taken mine off the market and am considering getting an LPG conversion. I've looked at the threads but I get a sense that these conversions are that reliable. Is that the general consensus?

Any recommendations of where to go too?

Regards,
Dave

[goose]

all i know is if i were in the market to buy a german V8 4 dr exec sal/est, i would steer clear of one that had been converted as i would be nervous of whom did the conversion, and the long-term reliability

just my 2p

goose

[gottanS]

Not a fan of lpg primarily due to safety concerns, the stuff doesn't have a smell so you could have a leak without knowing it with potentially serious consequences. Financially it only makes sense if you are doing a lot of miles and assuming the current tax level stays the same. Personally I wouldn't buy a converted vehicle second hand as goose above says, too many unknowns.

[1781cc]

I have had my car for 2.5 years - 2 of which have been with LPG. I haven't had loads of issues, but I have had a few offset issues from the conversion - namely:

- thought it was misfiring on LPG, turned out to be the airbox flap was sticking above 5000rpm, MRC sorted this, apparently its common on RS4 V8s
- I had a failed LPG vaporiser, it turned out to be a defective part from the BrC factory, replaced and OK - just meant the car wouldnt run on LPG at the time, so no damage
- I have also had a few issues with coil packs, LPG is denser than petrol and puts coil packs under more load. these things are shoddy at best in petrol cars let alone one with LPG, so I keep a few in the boot, I last changed one 9 months ago.

The common misconception with LPG is that your car just runs on gas, actually, its a bi-fuel car post conversion. so you can switch it to run on either petrol or gas. Typically, if I am doing short trips or having a blat, I turn the gas off with the dashboard switch (cause on gas you lose a little power because its a denser fuel and takes a little more to spark), but on longer trips, motorways, commutes I run it on gas.

if you do decide to have a blast on gas or use it day-to-day, remember that it starts up from cold on petrol, then and only when the engine is warm enough the car's ecu switches to gas seamlessly, in your setup process during install you can specify if you want a gas run-limit. Mine is set at 5000k - so, if I am on gas and play hard it switches over to petrol automatically and stays there till you switch it again.

finally, I have a small donut tank in the spate wheel well, its 70 litres - costs me £36 to fill up, which is half the price of a tank of petrol, I essentially get two fills for the price of a tank of V-Power. with each tank I can get 175 miles, so thats 350 miles approx for the same spend when I would usually get about 220.

If your keeping the car for a long term, like me, and you do a lot of miles, the difference is huge on the wallet. Plus, no congestion charge in London and £20 off your annual road tax.

[1781cc]

Not a fan of lpg primarily due to safety concerns, the stuff doesn't have a smell so you could have a leak without knowing it with potentially serious consequences. Financially it only makes sense if you are doing a lot of miles and assuming the current tax level stays the same. Personally I wouldn't buy a converted vehicle second hand as goose above says, too many unknowns.

meant to say, Gas definately has a smell, its the additive that they put into it before it hits the pumps - trust me, after your first fill at the pump you will know what its like as you get a very small burst of excess when you disconnect the nozzle - its unmistakable.

If you contact the greenfuel company and as regionally where there are fitters you can go along and have a chat. The LPGA are pretty strict with who is approved to do installs.

[xyber]

I'm not a fan purely because of how it looks under the bonnet.

If it could be injected through a machined manifold that sits under the inlet manifold like a nitrous kit I'd consider it as it would be hidden

[1781cc]

I see your point on the visual side, but personally I dont mind it, I just go in there for oil, water and when I have to for other mechanical reasons. so not too fussed about how it looks.

[spikeyboy101]

I think my matsh may be a little off.

Not sure what your doing to only get 220 miles out of a tank of petrol.

My S4 costs approx £85 to fill up and i will then do 300 miles on a tank.

Your saving that the LPG costs £36 to fill up and you will get 175 miles from this.

Make these items equal:

Petrol is £85 for 300 miles.
LPG is £62 for 300 miles

A total saving of £23

How much did the LPG conversion cost ? say £2,000

So before you brake even you have to run 26,000 miles

[1781cc]

what I usually do is drive the car hard on petrol, dont know if your car is immune to increased consumption when you rev it higher, but mine is certainly affected by it. hence the 220 miles.

If I am driving on Gas its more economical and thus I dont usually go about about 4k rpm, part of my thinking was that I built the cost of the conversion (£1800) into the purchase price of the car, then over the long term my running costs are lower at the pump day-to-day (because being self employed means my monthly income isnt always gaurenteed)

It wasn't about getting a return on investment for me, because if it was I wouldnt have bothered with the racing downpipes and the decatted non-res miltek system (which ran to about £1600 itself all in)

My plan is to keep the car for around 5 years (unless something changes in my circumstances) and if I am doing around 15K a year it wont take long to save money anyway. I am already 2.5 years in and have done over 30K so even on your maths it looks like I have passed breaking even.

[spikeyboy101]

Dont get me wrong - i wasnt dissing that you had done the LPG conversion - just trying to bring more light to the equation.

I suppose if you were only using pertrol for the heavy foot driving and LPG for the light foot then this would explain why you were only getting 220 miles from a tank.

Trust me i drive mine hard and on average would return 300 miles to a tank. (split between hard twisty driving amd motorway crusing).

Yep looks like you in the money now - say just keep on driving

[RSKiwi]

Dont get me wrong - i wasnt dissing that you had done the LPG conversion - just trying to bring more light to the equation.

I suppose if you were only using pertrol for the heavy foot driving and LPG for the light foot then this would explain why you were only getting 220 miles from a tank.

Trust me i drive mine hard and on average would return 300 miles to a tank. (split between hard twisty driving amd motorway crusing).

Yep looks like you in the money now - say just keep on driving

Spikey are you getting 300miles from your B7 RS4???????

I need some of your driving magic as I can only dream of that mileage if you are!

I get 220-260ish on average.

[1781cc]

I can only think that he has a Schumacher-eqsue ability to save fuel while going fast! (jealous)

[spikeyboy101]

Nope that was in my 2003 S4 Avant (with a few mods). Most i ever got was 350 miles on a run down to Cornwall.

Only had the RS4 a week so havent found out how many miles yet. When i filled it up it said 340 miles on the DIS.

I do tend to read the road conditions ahead quite well, so if i see i need to slow down i just let the car coast up, rather than carry on full speed and brake at the last minute.

country roads is when i tend to give it the beans, motorway im cruising, wont say the speed on here, lets just say that its quicker than the sat nav says i will get there