Go LPG - LPG conversion -Brief description
LPG Conversion - A Brief Description


This article was written to give a brief idea of what it is like to have your vehicle converted to run on LPG or Autogas, the differences you will encounter and the savings you will make on your fuel costs.

The main points can be expanded by choosing the links and the rest of the website should have the answers to most of your remaining questions. Hit your browser's 'BACK' button to return to this page. More choices are available from the left bar.


An Alternative Fuel.......


Although LPG (Liquid Petroleum Gas or Autogas) is a fossil fuel, it is much cheaper to buy than either Petrol or Diesel. Far less Tax is added to the pump price because it makes far less pollution. Europe and the UK Government want to encourage the use of LPG as an environmental issue. As a result we only pay 6.5p per litre fuel duty on LPG, whereas Petrol and Diesel are loaded with over 60p per litre. This gives us an alternative road fuel costing around 1.55 a gallon instead of 5 or so.

The benefit of LPG, in a few words, is that it will save you half of the money you used to spend on petrol, it really is that simple.

LPG is easy to find these days, there are at least 1250 stations selling it across the UK. We provide a handy glovebox size map of the whole country showing every station, its address and telephone number. That makes LPG motoring easy.

For more on LPG itself read 'What is LPG?'

Gas conversion of vehicles in the UK has its roots in the Petrol shortages of World War 2.

Cars, Vans and essential vehicles such as Ambulances were converted to run on ordinary Town Gas. The Gas was carried in huge bags mounted on the roof. These days, we've managed to get the size of the Tank down a little, mainly by using LPG as it takes up far less space for the amount of energy it releases.

Whilst the UK returned to using Petrol when the War ended and supplies were restored, Holland and Italy weren't so lucky. They couldn't get sufficient petrol for thier needs and had to develop alternatives. This is why most LPG equipment used in UK is made and imported from both of those Countries.

The Government's current freeze on LPG road duty and the 'tax break' it gives us will last until April 2009, during which time the environmental benefit of using LPG as a road fuel must be proven. The industry is busy making sure that this happens. When it is done, more extensions to the 'tax break' will be granted. The upshot is cheap road fuel for more than the time you or I will own our next car.

For the last 3 yrs, Petrol has been 2.4 times the price of LPG in our area (bought from private sites as opposed to forecourts). This means that a car giving 20 mpg on LPG is giving its owner effectively 48 miles to the gallon on a pound for pound basis. Although the savings made are still considerable (half of your petrol money) when your LPG is bought from a forecourt, we encourage you to find a local private supplier, making your savings even greater.



The Conversion


Almost every LPG Conversion done in UK is of the 'Bi - fuel' type. The vehicle will still run on Petrol and most likely retain its original petrol tank. Because petrol operation is retained, all dual fuel LPG conversions effectively give you a useful reserve fuel system. This also allows you to extend the vehicle's range quite considerably. Take a look at 'LPG conversion' for some more info.

An LPG tank is added so some boot / load space might have to be be used or perhaps a spare wheel displaced.

The conversion makes no difference to the safety or ordinary servicing of the vehicle or its MOT test. When your car is due for MOT you have the choice of having it tested as a Petrol or LPG vehicle, it does not have to be tested on each fuel. LPG conversion does not harm the engine or the rest of the car in any way and actually brings great benefits of reduced wear and corrosion. You must inform your car's insurer if you have the car converted because it is a vehicle modification.


Which type of conversion would be best for your car?

ANY good quality petrol engine can be properly converted as long as the correct type of conversion equipment is used. Find out which type of conversion would suit your car.

Note that Turbocharged and Supercharged engines can be converted. Go LPG specialise in both.


LPG Tanks


As we said earlier, your car must have an LPG tank fitted, along with a filler point and a fuel choice switch. The siting (and fitting) of all of these components is subject to regulation, i.e. that the filler point must be fitted on the outside of the vehicle (for instance). The size of the LPG tank should be suited to your range needs and balanced against the amount of load space you can afford to lose. The position of the switch and filler point are very important for your future comfort. You should discuss the available siting choices with the converter before conversion takes place.

Note that you may need an Adapter to fill up with LPG in other countries, even within Europe.


Fuel Choice Switch


The fuel choice switch will be placed within easy reach of the driver. This switch will include some form of LPG fuel gauge, normally 4 green LED's representing 1/4 of a tank for each one lit. In addition, the switch will probably have 2 more LED's, one that is lit if running on Petrol (RED) and one that is lit when running on gas (AMBER).

NOTE LPG gauges are notoriously inaccurate and are best ignored!

Most LPG users will zero their trip meter after filling the tank and use that as a guide after getting used to the mileage their car will cover on a full tank.

The only time you can be sure your tank is full is when you just filled it, and the time you know it is empty is when the engine fails to respond, or with later injection systems, the system cuts back to petrol, Often the LPG gauge will show the red 'reserve' light for 100 miles or more, but that does NOT mean the tank is empty or even close to it.

Your actual tank capacity (minus 20%) is on the pressure vessel cerificate.

The colour of the LED's varies between manufacturers as seen in the picture above, although almost all of them use green LED's for tank contents and have a Petrol and LPG symbol of some kind close to the LED that indicates which fuel is being used.

The fuel choice switch allows you to choose between fuels instantly whilst driving, bringing an added benefit - If you run out of LPG, just select Petrol and carry on with your journey. Some of the latest conversions will even do this for you!

For more on having you car converted see What Is Involved

We often have cars for sale already converted - See Converted Cars for Sale


Having your Car Converted

You'd be wise to use a reputable conversion company, ensuring that the job is done safely and properly. You must inform your insurer of the conversion, preferably checking that they are happy before you proceed. Note that most major insurance companies do not 'load' (increase) a premium as long as the conversion is carried out by qualified personnel and properly certified.

When choosing a conversion company make sure you will get a warranty on both parts and labour and a conversion certificate for your insurer. Keep the latter safe and only fax or post a copy to the insurer.

It is absolutely crucial that the correct type of conversion is fitted to your car. Inappropriate conversions can cause unreliability, damage to the engine or catalytic convertor or simply be a plain waste of money if too complicated for the application.

The mileage your car has covered before conversion presents no barrier if it is high. There is no mileage limit at Go LPG. All that we require is that the engine runs well on all cylinders and that it has a very good ignition system. We examine every car before conversion is commenced and will advise you if any faults exist, and suggest ways of rectifying them.

To make the whole conversion experience go smoothly there are many ways you can help.
See 'Smooth Conversion'

NOTE that many things can delay a conversion, right from late delivery of conversion equipment or an unforseen problem arising in the conversion process or even the car itself. Mistakes can be made under the pressure of meeting a deadline! In these situations it is not wise to press your converter for an early return of your car. Better to wait a day or two extra and get a fully tested conversion and not have to go back with any type of problem.

It is very unwise to wait and have your car converted shortly before a motoring holiday. Go LPG (for instance) can only road test a freshly converted car for 50 miles or so, after that it has to be left to the owner to report any anomaly and, if necessary, bring the car back for attention. This process is greatly aided by staying local for the first week or so. We do understand that you want to make savings on what is probably the most intensive motoring in your year, but what happens if an anomaly shows up and you are hundreds of miles away from your converter? They won't be able to help by phone and specialist conversion companies are not easy to find in a strange area. Much better to get your car converted at least a month prior to your motoring holiday, allowing the car and conversion to have a 'bedding in' period, also allowing you time to get used to using the system and filling the tank. Then you can ride off into the blue yonder with confidence and save more than fuel money. You might save yourself a lot of potential problems.

Suggested link 'Our Standards'


Grants for conversion

Although it was (up to August '05) technically possible for a private person to get a grant of up to 60% of the conversion cost on a car less than 5 yrs old, we ( Go LPG ) have never met one single person who successfully claimed such a grant. Also be aware that 'qualifying' conversions are often twice the price of any other.... It is our opinion that the 'Powershift' scheme was nothing but smoke and mirrors.

DIY conversion

It is possible for those with a lot of vehicle or engineering knowledge to convert their own car very well but it is unlikely that they will have all of the specialist tools required to do a first rate job . Also beware that that the finished conversion would not be certified for insurance purposes or have any warranty. Suggested link 'Can I convert my own vehicle?'



Driving a Converted Car

A good conversion using quality components, properly installed and adjusted, should make the engine perform just as it does on Petrol. There has to be some power loss (LPG is 15% less potent when measured against petrol) but this is only evident at the highest part of the RPM band. When driving a converted vehicle with a larger engine it is very difficult to find any difference in performance. Vehicles with smaller engines might show the power reduction more clearly but we are still only talking about a minor amount toward the top of the rev. band. Not a big deal for most drivers as we rarely 'red line' the engine on today's roads.

Suggested link 'Will the performance of my vehicle be any different after conversion?'

If your vehicle has cruise control it will work just the same on gas.


Fuel Economy when running on LPG


LPG has slightly less energy (15%) than a similar amount of Petrol. As result, you will get slightly less (15 - 20%) miles per Gallon or Litre. That hardly matters because LPG is almost always (*see below) less than half the price of Petrol. To avoid going through all the arithmetic is it safe to reckon on saving half of the money you used to spend on petrol before conversion.

*LPG Pump Prices


The price of both LPG and Petrol are governed by the price of crude Oil. Whilst the price of petrol can go up or down very rapidly, the price of LPG is quite slow to change. This is due to the vast amount of petrol being sold every day - 32 million vehicles run on it. Conversely, there are only 170,000 vehicles running on LPG to date. LPG stocks are naturally sold more slowly and pump prices will represent the price of crude oil (and LPG stocks) bought a month or two ago, whereas petrol prices may reflect the price of crude only a week or so in the past.

Recently we have seen the price of petrol go down very quickly, temporarily eroding the price advantage of LPG because takes longer for LPG prices to reduce.

This can be seen in negative way unless the reverse process is also considered - When petrol prices go up, it takes a lot longer for the pump price of LPG to go up. Several times we have seen the price of LPG effectively made one third of the price of petrol by exactly this process. It has been the more pleasing effect of LPG pump price intertia. Over time, the long term price differential beween petrol and LPG finds its own level and is maintained at the historic level - LPG average prices per litre or gallon are 45% of the price of the same amount of petrol.


Day to Day Fuel Management

It is important that the engine is started from cold on Petrol, warmed up whilst driving and only switched over to gas when fully hot. Note that most later type LPG systems will not allow you to switch to gas unless a pre set engine temperature has been reached. All SGi (Sequential Gas Injection) conversions fitted today will automatically revert to petrol for any start, and will only change over to gas when approximately 1600 RPM have been attained, then allowed to reduce back to idle. It may sound complicated but you'll be used to it in minutes. The Driver does not even have to understand how the changeover works for the system to function correctly, no input save setting the switch to the gas position is required.

When driving a converted car you must keep around 1/4 of a tank of Petrol in the tank at all times - Not only does this give you a valuable 'reserve' should you run out of gas, but is essential to keep the petrol pump 'wet' when going uphill, downhill or round tight bends at speed. The petrol pump will still be running during LPG operation (and should be for many reasons) and may be damaged if it runs 'dry' whilst running on gas. As you use petrol for warming up from a cold start, replenish the reserve as required, thus keeping the tank contents reasonably 'fresh'.

Regular replacement of ordinary service items (ignition components, air filters etc.) becomes a little more important when running a converted car. If you try to skimp on regular servicing this might just come back to haunt you later on.

Advice for you to Consider

1. LPG is less potent than petrol. As a result, your car will return around 15% less mpg per gallon or litre. This does not reduce your chance to save at least 50% of your fuel costs, as LPG is far less than half the price of Petrol. (At today's prices, we are paying 115p per litre for unleaded and .47p for LPG, September 2008).

2. Always keep at least 1/4 of a tank of Petrol in reserve. On most conversions the Petrol pump is still running whilst using LPG (for good reasons not discussed here). If the tank runs dry whilst you are running the engine on LPG the Petrol pump can be burned right out as it relies on Petrol to lubricate its bearings and cool it down. Fuel 'slosh' when going round corners may leave a Petrol pump to run dry if there is only a gallon or so in your tank. This is why we recommend 1/4 of a tank to keep the pump 'wet' at all times.

3. Make sure you use and replenish that 1/4 of a tank of Petrol in rotation - Petrol over 3 months old will have degraded to a greater or lesser degree and may not even be capable of running the engine at all! NOT what you want from a reserve fuel!



LPG - Where to Buy it and How to Fill Up.......

Filling your LPG tank is easy enough but it takes about twice as long as Petrol. That's OK with most users, there is rarely a queue and it's less than half the price!

If you want to fill the tank right up (most people do) then be assured that there is no chance of overfilling it. Both the LPG pump and the tank have mechanisms to cut off the supply when the tank is full, even if you are still hanging on the button.

LPG filling stations are just about everywhere these days, Motorway services, ordinary forecourts and private sites such as Farmyards. You may not have noticed any before thinking about conversion, but you'll soon develop an eye for them when using the fuel. LPG sales sites can easily be found on the Internet with a little research and it is a good idea to check up on any area you are visiting. Many users keep notes in their gloveboxes if they visit an area infrequently. Some will keep the supplier's phone number and ring in advance, making sure they are open.

One of the best ways to find LPG stations is to get the Autogas / LPG Map.

Find out more about the Autogas / LPG Map


And finally, DO ask around......Many private sites supply very cheap LPG but they are often tucked away, the best way to find them is by word of mouth. People filling up with LPG are normally a cheerful lot, ready to swap a tale and share their knowledge of good sites with you. It really is quite refreshing in this day and age!

Going on motoring holidays abroad is no problem as long as you take the correct filler adapter.

LPG in Europe. Ireland has good supplies. France and Belgium have plenty of LPG (GPL) outlets. Italy has one on every corner, Germany is great and Spain has just (July 2004) begun to allow sales of LPG to private motorists (up to date it was only available to Govt. vehicles)

Remember that an LPG powered vehicles cannot currently use the Channel Tunnel, whereas the Ferry Companies have a much more sensible attitude.


The Savings........

Because savings are made during every mile you drive on LPG, they build up rapidly, but those savings are directly proportional to how many miles are covered. Drivers that cover a lot of miles will therefore 'pay' for their conversion a lot more quicky than those who drive less.

Don't be fooled into thinking that only late model cars with large engines are worth converting - The driver of a 1000 car using 60 of Petrol per week is spending 3000 a year on petrol - Halve that fuel cost (1500) and the conversion (1500 for example only) is paid for in 12 months. The next 12 months will produce a further 1500 saving and pay for the 1000 car itself, with 500 left over.

Whilst a lot of people tend to focus on what their car will be worth on the used market when they come to sell it, this is hardly even worth considering in our example above. Clearly, the major cost of using a 1000 car for just one year is the fuel cost, not the cost of the car, and this is far more significant.

When you have done your time with the car and want to sell it on, it is worth remembering that a converted car is always easier to sell and will command a much higher price. The LPG motorist wins in many ways, not just on fuel cost.

We have explained the savings in fuel costs in depth elsewhere on the site so for now let's just say that an LPG conversion will save you at least HALF of what you normally spend on Petrol. Do remember that like other fuels, LPG will vary in price too. Seeking out and using local private suppliers can save you even more money!

You'll also be doing a lot to help the environment as LPG Carbon Dioxide emissions are a lot lower than those of Petrol, along with other poisonous products.

Other savings may be out there to be made. Read 'Other benefits' to find out how some drivers save on parking charges etc.


The Drawbacks.......

Yes, there are some.

If you want to have your car converted, it will have to have an LPG tank fitted. That tank has to go somewhere and you will probably lose some load or boot space. How much will depend on your tank choice (size, shape and position).

You will have to put in a sum of cash up front.

You will not have the pleasure of queueing at Petrol pumps ( ! )

Diesel conversions are not currently worthwhile.

Filling an LPG tank is slower than Petrol.

An LPG converted vehicle cannot (currently) use the Channel Tunnel.

Some cars have engines with very soft engine valves and are not suitable for conversion
(See Valve Seat Recession)

For owners of new or recent vehicles -

Be aware that many Car manufacturers have a poor attitude to LPG conversion and will use it as an excuse to void their warranty on a vehicle. Check that they agree with conversion before having a new(ish) car converted or be prepared to arrange another warranty in the marketplace.


'Powershift' Grants for LPG conversion

Powershift grants were almost impossible to secure, and when 'granted' the conversions undertaken were often twice the industry price, leaving you to claim half of the cost, which was pointless.

JULY 2005 - As far as we are aware, the Powershift scheme has now been discontinued, allegedly because of a European directive which forbids any sector of industry in any EEC country from having an unfair advantage. No form of granting for LPG conversion now exists in UK (to our knowledge).


Road Tax Reductions and freedom from Congestion Charging

The best thing to do with both of these mirages is to forget them. It might be just barely true to say that they are possible to acheive. The reality is that you have to jump through many hoops, only to find out that your car is not eligible for the relaxation of congestion charging.

In the case of road tax reductions, we get a lot of enquiries about that. There is a reduction of just 10 or so a year but this is the wrong thing to focus on. LPG (before tax) costs about the same as petrol per Litre or Gallon, but is much cheaper at the pumps because of the massive reduction in road fuel duty applied to it. That is a far larger tax saving than any reduction in road tax could provide.

In our opinion, it is not worth wasting the time, money and effort that you will put into chasing either of these things.

Just take the major saving - Half price road fuel, and save yourself a lot of bother.




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