| I have converted my new Mini Cooper to LPG. I had a few teething problems but now she runs great.
Due to the nature of LPG it needs a reasonably warm engine before it can be used. The fuel is stored as a liquid and a vapouriser converts it to a gas prior to injecting it into the engine.
The LPG conversion ECU works in tandem with the Mini ECU and is slaved off of it. Once the engine is warm enough the ECU switches over to gas.
Modern LPG conversions use sequential injection which switches a cylinder at a time over to the gas so you do not feel the switch. The only reason I know the car is about to switch on to gas is the fact I can hear a small clank noise coming from the LPG tank which starts the flow off.
Performance is marginally down but not much. However, I can still by the click of a switch move back on to petrol when I want to play.
As for MPG, it averages 36 which based on the price of unleaded equates to 72MPG.
Things to bare in mind when converting:
Your insurance company needs to be informed.
The DVLA needs to be informed
It will cause problems with your warranty (or it will on the engine), however a comprehensive engine warranty can be purchased over the internet for around £100.
I have lost my boot space, but, I do 230 miles a day and the conversion will pay for itself in under 12 months.
Check your installer is LPG association approved and the kit has a warranty (generally two years)
As for back firing and engine lights. I have never had back fire and although the EML appeared a few times, a quick bit of tuning on the laptop and 4000 miles later it's been fine!
Any questions, please ask!!!  | 
