# How to improve LPG Engine MPG performamce



## SwannP1 (Aug 9, 2015)

Good day,

I have an American RV which is R-vision Trail-Lite (2001). It has an LPG engine with Petrol backup. I am achieving only about 7 mpg on the LPG 
I would appreciate any advice on how to improve this? Should I take the vehicle to an LPG installer for review? Any other ideas :sign7:

Thanks 
Paul


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## listerdiesel (Aug 3, 2012)

If it is a simple single-point injection system, you won't get good results.

Multi-point injection using the vehicle's own engine management system to control it is the way to go.

Peter


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## nicholsong (May 26, 2009)

Paul

What consumption does it do on petrol?

From my experience of LPG/Petrol vehicles the LPG consumption is 15-20% higher.

Geoff


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## Mrplodd (Mar 4, 2008)

Paul

I think you will find that the vehicle started its life with a petrol engine and, because of the horrendous fuel consumption, (which wasnt a problem in the States where petrol costs up until a short while ago were simply not an issue) has had an aftermarket LPG system installed at some stage 

It is well documented that an LPG conversion will give LESS mpg than the petrol engine it is fitted to. The reason being that LPG has a much lower calorific value than petrol (it doesnt provide as much energy when burnt, therefore you need more fuel for the same amount of bang!!) Hence the lower MPG figure. 

The reason LPG conversions are fitted is that the higher consumption is off-set by the much lower cost of LPG

There are a lot of petrol engined American RV's on the market and the prices often seem to be very reasonable (even if fitted with LPG conversions) the reason for that is simply the running costs (8 mpg) !!!

Some will look at the overall cost and accept that they will have to pay a lot for fuel but that cost will be offset by the lower purchase price of the RV, and over a few years it will all level out. It all depends on your holiday style. If you go somewhere and stop for a couple of weeks that could be the casze, if you like to tour a lot then I am afraid you will need some VERY deep pockets. 

Andy


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## gaspode (May 9, 2005)

I would have thought that 7mpg was an average sort of figure for an RV with an LPG conversion?


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