LPG Conversions - One way to make your journey greener

To kick start things of here at my WinACC blog I thought I'd start by posting about a topic that is close to my heart when it comes to being greener. It's future fuels and in particular, LPG.

The following is an account of my LPG conversion done to my beloved BMW 323. It was done some time ago and I've only really got round to putting some words together.

The Car

The car was a BMW 323 SE 2.5 litre 6 cylinder auto. That might not mean too much to some people but in a nutshell it was refined, quick, comfortable but not in the slightest bit economical or eco friendly.

On a good day I averaged 25 mpg, on a bad day maybe 15. It was nice though. And here's a picture of it.

Why the BMW

I was commuting 110 miles each day and I wanted something fast, comfortable, safe and luxurious. So I plumped for the BMW safe in the knowledge that I had enough cash left over to pay for an LPG conversion.

I'm not a fan of diesel cars. Firstly because of the unknown long term damage diesel *could* cause (localised asthma, localised air pollution - there are no long term studies) and secondly because of the way they drive and the noise they make.

The BMW set me back £3300.

The Conversion

Before going ahead with the conversion I checked the local filling stations to make sure there was one near me. There were two as it happens and at the time, the price was about 48p per litre. Bargain.

The conversion was carried out by a local fitter who also happened to be a government advisor on future fuels. The car was booked in for 4 days and when I went to pick it up it was now officially a dual fuel car.

The conversion cost a little more because of the extra two cylinders and came it at a very reasonable £1500.

Dual Fuel?

The LPG conversion I did essentially allowed the car to run on both LPG and petrol. The car always starts on petrol and when the engine is warm enough it would switch automatically to petrol. I could over-ride and switch to petrol at any time as well.

The system

The system was a Prins VSI multi point injection with a donut tank in the spare wheel well. The spare wheel simply sat in the boot. The filler cap was located just below the petrol cap and an in car dash control was mounted just below the light switch.

The system did add extra weight to the car which did affect the handling, but I never drove the BMW on the limit anyway so was never adversely affected by it.

Filling Up

This is actually really straight forward once you've done it a few times. At first it is daunting and can take a few attempts to get the hose connected.

There are a few things to consider when filling up. The LPG pump is normally located on the first petrol pump near the entrance and usually slotted between diesel and petrol. What this means is that it is always the busiest pump in the garage, even though very few people are using the LPG pump itself.

You may find occasionally that you have to sit behind someone filling up even though all of the other pumps are free. Lesson number 1 on how to freak someone out at the petrol station.

Refilling also takes a very long time. What this means is that if there are 2 or 3 cars in front waiting to fill up then you could be there for at least 30 Min's.

When the car is full and you release the connector it gives out a puff of gas. This is perfectly natural but does smell a little when you get it on your hands.

Despite the above, filling up is quite straight forward however I do have a few major gripes with the refueling aspect.

1. The in car LED is far from accurate. It very rarely shows as full and remains on empty for most of the tank. The best way to counteract this is to work out how many miles you get per tank and simply check on the trip computer.
2. The tank I had fitted was not large enough meaning I only got 300 miles per tank. On a commute of 110 miles a day I was filling up every third day roughly.
3. The LPG pumps at the forecourt often don't work in really cold temperatures so try to fill up during the day.
4. Most staff in petrol stations do not know how the LPG refueling system works so if you get stuck more often than not, they won't be able to help.

The performance

The performance was affected slightly, mostly by the extra weight I was now carrying due to the tank. With a big engine like the 2.5 it stilled pulled nicely and was pretty much the same driving experience on LPG as it was on petrol round town.

On a steep hill though the LPG system appeared to struggle and I had to keep kicking down the auto box to get it to maintain speed. Could have been something to do with the auto box and the engine management system....

The Extra Costs

Apart from an annual service of £35 the LPG system cost me nothing extra. The insurance company were fine as long as provided a certificate. The resale value was more (I have since sold it) and the system plus installation was covered for 5 years anyway.

The Running Costs

The money saved was one of the most important aspect of the conversion for me and the good news was that I was saving a fortune. I was achieving around 25mpg on LPG which is to be expected for the size of the car. The thing to consider was at 35/40p a litre I was 'technically' achieving the petrol equivalent of 50~ mpg. This calculation is roughly based on LPG being half the price of petrol.

The fact I could run a BMW with the legendary straight six engine and still get 50+ MPG was fantastic.

Environmental Impact

In terms of environmental impact, it's not a silver bullet. As the engine was huge and I was doing lots of miles it would have still been kinder to the environment to run a smaller more economical petrol or diesel car.

But that defeated the object of my experiment and trial. I wanted a big engine car but didn't want the guilt that came with it. I also didn't want the cost...So running a small engine or diesel car was never an option for me.

Despite the fact I do my bit to help the environment I'm a self confessed car nut and the two sides of me are always at war. I have now found a good compromise of performance and economy.

So if a huge car with a huge engine is what's important to you but you want to do your bit to lower your carbon footprint and save this wonderful city called Winchester then you could no better than having your gas guzzler converted to LPG.

Rob