Converting a V6 to LPG

[Charles M]

I did have a quick search but has anyone here converted a V6 (either series 1 or 2) to LPG? I loved the V6 I was taken out in on Sunday, but while the fuel economy is decent for a larger engine, ultimately the mpg would kill it as a long term ownership prospect for me. So I would be interested to hear if anyone has done / bought one with an LPG conversion and whether it works mechanically and economically, I assume the tank goes in the spare wheel well?

Having an SM that averages around 15 mpg (if I am being optimistic) I can't afford my daily driver to be un-economical!

[CitroJim]

I'm aware of a very successfully converted Xantia V6 and I do know of a currently non-functional XM V6 conversion (the gas bit, not the car).. Generally they're good and work well..

I've had experience of running a TCT on gas and my only real observation is that if you do then go for a big boot mounted tank rather than the titchy toroid that live where the spare wheel did for two reasons: the toroid is good only for about 200 miles and you’re always filling the damn thing up and I hate going anywhere with either no spare wheel or one floating around in the boot although a Volvo space-saving biscuit can be used.

These days there's no end of filling stations around selling autogas so it's more an aggro thing really with a small toroid...

LPG runs cleaner than petrol and it can be easier to pass an emissions test with it.

Downside on the S2 ES9 V6 is limited space to install the big vaporiser that's needed and the difficulty of making a really neat job of fitting the gas injectors to the inlet manifold.

I've not yet seen what I call a truly tidy installation on one.

Also, if you do go down the gas route do go for a well-known brand and not some unknown one. Something like Tartarini.

Lots of LPG kits now originate in Poland as they are very big into LPG. They are said to be very good but do check the availability of spares on a long-term basis as all gas systems have components (vaporiser and injectors amongst other things) that have a finite life...

If you travel in Europe a lot be aware we use the 'Dutch Bayonet' filling valve and few others do. The Dutch and the Irish do and that's about it. You need to carry adaptors for the more common European ones...

You can DIY but getting the installation certified (which is a must for legal reasons) can be very difficult unless you can secure the cooperation of a qualified automotive gas fitter from the very start who can advise and see the work in progress...

[MTXM]

I have had a little bit of advice on converting one of my S1 V6, which would certainly reduce running costs, although the quote was around £1,200, ie. almost the value of the car! On the Forum we have Paul (Citroen XM) who is the resident expert on conversion of the PRV V6. Regards, Matthew T.

[citroenxm]

Well what can i say.. i have ran a v6 s1.5 prv auto xm for 40k miles on lpg and loved every second.

Where is she now? Well i still have her. The current engine install is well over 200k. However the use of an equivilent 40mpg and V6 that makes a v8 induction noise was stunning. I had the car on the road before i started rally attending.

The car is sitting awaiting resto and looking rather sad needing bonnet both wings nose cone for the body due to laquer lift. The engine. Ive a 60k engine and box to go in. The car will remain on lpg and unless i fall in love with her again would be interested in selling her on. But it wont be this year..

Would i recomend it?? Yes i dam well wood.. but mine has the easier to install mono point system on it. The prv would benefit from a multi point injection or sequential injection system nicely.

PS. The inside of the rocker covers and timing gear were soooo clean you could eat your dinner out of them.. Honest!

[Charles M]

Thank you, that is very interesting indeed. There is absolutely no danger of me fitting one myself!

As is always the case the car would have to be run for more than x per year in order to make it pay. I think in the first instance a diesel is the best place to start, then as my fleet reduces (3 have to go) a V6 would make more sense.

[citroenxm]

Depends on the cost of the lpg install.. the kit i got was already on another v6 xm i bought for 200 quid for spares and i simply swapped it over.

Get a 2.1 td manual and you wont want a v6.. however. Get a s1 24v manual xm and the sm might feel slow to you then..

[Charles M]

True about the cost.

The SM is quick, but it's not a sports car (the heft sees to that). It takes a lot of revs to get it shifting, but then it's a Maserati engine and the revs are what you want! I have contemplated having modern engine management and injectors put on it, the flywheel has been changed to support a crank position sensor, but it's a lot of money. However, it would then give me a very much faster and more economical beast. Given how used I am to Diravi, the 24v valve would have to have that!

[Assich]

If it is the ES9j V6 then make sure the kit works well with a semi sequential injection system. With the auot gearbox talking to the engine ecu not every lpg ecu ssytem likes the way it changes the injection firing.