Hidden costs of LPG conversion

Still using petrol

LPG converted engines usually run on petrol when they are colder and switch to LPG when they are warm enough (at around 35 – 40°C). That is why the car will run on petrol longer in colder conditions. A thing to consider if you have a lot of short routes on which the engine doesn’t have enough time to warm up.

Consumption increase

Although LPG has a higher octane rating (up to 110+) than petrol (90 – 100) and higher energy value (46,1 MJ/kg) than petrol (43,5 MJ/kg) it still has lower energy density because of the lower liquid density (0,5 – 0,58). Petrol has 0,71 – 0,77.

That is why the consumption (liters per 100 kilometers) is always higher with autogas compared to petrol. On average there is a 20% increase in consumption, but it depends a lot on different factors, so it can be lower or higher.

LPG Service

Autogas systems have servicing intervals at about 20.000 kilometers or 1 year. Usually the mechanics check for any leakage, change the LPG filter and run a computer diagnostics. Because the costs can go from 20 to 100+€ some people don’t want to service the system until it is too late.

Additional lubrication for LPG

Certain engines require additional lubrication of valves to prevent valve burning, loss of compression or engine failure. Add around one liter of lubricant for 10,000 kilometers to the expenses.