The UKLPG association is responsible for monitoring the workmanship of LPG conversions. LAS Motorhomes have been a member of this association for 10 years now, and during this time have completed hundreds of LPG conversions on American RV Motorhomes.
One thing that is difficult to explain is the variation in prices when requesting a quote for this work. The difference in price can be as much as £2,000.00, this can make you think “Are the higher priced quotes a rip-off?”, and “Are the lower priced quotes a bodge?”
LAS will try to explain some of the work that goes into an LGP conversion on an American RV Motorhome. The parts that are used to convert the engine come as a kit. These kits are made by various companies, therefore come with different quality grades. China, Poland and Korea make many of these kits but they are of poor standard. The ones made in Italy are fair and are perfectly adequate for a car, but are not suitable for an American RV Motorhome. All these things have one thing in common and that is they are cheap to buy.
If you need a Ford 6.8 litre engine converting, then there are not many kit manufacturers that can supply a 10 cylinder system. Most will fit 2 x 5 cylinder kits, which will not work correctly after 2005 when Ford changed the engine to 3 valves per cylinder.
Then we come to the size of the injector. An American RV Motorhome takes a large quantity of LPG gas for most of the time, with the exception of when it is idling. To deliver this high quantity of LPG gas you will need large injectors, otherwise the engine will be starved of LPG gas when under load (run lean), which will then increase the piston and cylinder temperature causing extensive damage.
With most things nowadays they are controlled electronically. The LPG systems are no exception; they have an ECU (electronic control unit), similar to a computer they use software to control them. AEB is the company that supply the software on the more expensive systems. The cheaper systems software will operate too slow for the engines software; once again can cause the engine to run lean.
The other main component of the engine kit is the reducer. The job of the reducer is to increase the temperature of the LPG with the use of the engines radiator coolant. This will change the LPG from a liquid at -40 degrees celsius to a gas, and also control the gas pressure from 26 bar(380lb/sq inch), to a maximum of 2.5 bar (37lb/sq inch). An American RV Motorhome with a 6.8 litre V10 engine, or a 8 cylinder 8.1 litre engine will require two reducers, once again of good quality and capable of delivering large volumes of LPG.
As you can see that the quality of the engine kit is very important. As well as getting a kit with large capacity injectors and large capacity reducers, good quality ECU software that will work is even more important, so you just cannot go by just the price.
The other part of the LPG system is the storage, what we in the trade call the rear end! (The tanks). This is the part on where and how the tanks are fitted, or more to the point they must be fitted with safety in mind. The tank must be fitted on a frame to stop then moving and not allowing them to rub on another object, if this happened it could eventually rub a hole in them which could be very dangerous.
So let us re-cap, to carry out a safe quality LPG conversion, we need a quality engine kit with large injectors, a large capacity reducer with an ECU that is loaded with good quality software. The wiring will need to be neat and the injectors need to be fitted in a permanent manor (not just clipped with cable ties), as this has become part of an MOT. The tanks need to be fitted on frames, not just wedged in the chassis, and the supply pipes need to be clipped to the chassis with metal clips and not cable ties. All this takes time, LAS can take between 45 and 50 hours to carry out an LPG conversion, so you can now see that to get an American RV Motorhome converted to run on LPG for £2,000.00 might not be possible.
The UKLPG recently carried out an inspection on our premises on an LPG conversion which we had done on a Coachman Mirada. Mr John Walker was the inspector who arrived unannounced at the LAS workshop, just to see how we were (see we do have some friends). LAS had just completed the conversion which was ready for a road test, so we asked him if he could carry out an inspection on the vehicle (nothing like putting yourself under pressure), so he did. The Coachman Mirada was awarded a Certificate of Excellence in recognition for the high standard LAS has achieved on LPG gas conversions. Only 29% of gas conversions receive this rating. LAS were also thanked for maintaining the good reputation of the industry.