I'm considering a Cayenne on LPG, any advice welcome please

[Gary71]

Whenever I mention lpg conversions to anyone in our powertrain department they all twitch...

I was considering an lpg S8 until I had a long conversation about it and now fear terminal engine failure due to poor fueling, particularly on a high performance engine...

[Grindon]

Thanks for all the advice fella's.

I am not too concerned about the LPG aspect. I already run a couple of vehicles on LPG, so I know all about the pro's/con's of fuel consumption/performance loss. I haven't notice any real performance loss, but do feel that fuel consumption can be reduced by up to 20% with LPG, but of course the relative loss cost of LPG to petrol more than makes up for that.

With respect to high performance LPG, I think the vehicle should be OK as long as the LPG kit is fitted 'correctly' with 'adequately sized injectors' to take the power. Also, I hear that 'flashlube' kits should be fitted to protect the valves???

Anyway, not too concerned about LPG at the moment as I might buy one with the kit already fitted, or more than likely just not bother and enjoy the car - turbo here we come!!!!!.

Thanks again for your input, please feel free to add any thoughts on what to look out for on specs.

Cheers,


Kevin

[smallspeed]

LPG fueling issues are purely down to set-up.. it might be a problem on the old blow-through systems, but to be honest new sequential injection systems can be set-up almost as accurately as the stock (petrol) ECU depending on who's doing it and how good they are/how much time they're willing to spend

The most basic systems apply a conversion factor and basically multiply all the petrol injector outputs by this to operate the LPG "injectors" (valves) which is basic at best and usually over-fuels to be safe!
The newer systems with a better ECU can actually be mapped fully so you end up getting the most out of your LPG, minimising the difference in terms of performance (although partly at the cost of economy due to lower calorific value of LPG vs. petrol - this is not a problem on the continent as their LPG contains a %-age of butane to up the calorific value)

i would recommend a proper sequential system with a proper second ECU. This will take inputs from the stock ECU to make use of sensors and things but applies its own fuel map to control the injectors. This can be set-up near-enough and then rolling roaded to get just right.. No fear of under/over fueling assuming the system is in general good health (same as a petrol system) but I WOULD fit a flash-lube system for the sake of £50 and another £25 a year running costs. This helps prevent valves going dry and getting damaged, so good for peace of mind. If you can stretch to it the newer electronic systems (£100) are better than the old "pop bottle" / drip feed set-ups

HTH

ben

[Grindon]

Great info Ben, thanks for that and all taken on-board.

I'll not be rushing into anything (until I spot something I 'must have' )

Cheers,


Kevin