IWEMA enterprise
The power of LPG






Timing Advance Processor

Because LPG is a higher octane fuel than petrol the combustion time is longer. IWEMA enterprise therefore recommend that the ignition timing is adapted to the fuel. It is possible to change the ignition timing mechanically or electronically. This makes the difference between driving on LPG or petrol less. The fuel consumption and the engine power at low speed could be the same or even better than on petrol. Also the engine will run more smoothly and the exhaust emission values will be better.

There are several options to adapt your ignition to LPG:

  1. The easiest way is to give the ignition an additional advance of 3 degrees. Fuel consumption and performance will improve a little. But some engines, like a 2L Land Rover, might give starting problems, because of the lack of power of the starter motor. Another problem that might occur is popping in the exhaust pipe while decelerating.

  2. Another possibility is to install an ignition advance system which brings the timing back to the original timing (by retarding) when driving on petrol. Most of those systems however still start with a high ignition advance and might give the same starting problems as mentioned
    under 1.

  3. There are timing advance systems which use the original petrol advance. When driving on LPG they give an additional advance. The disadvantage is that the shape of the original advance curve is still used. Some are more or less programmable:
    • no additional advance on idle
    • no additional advance on deceleration
    • adjustable LPG advance.

Note that the maximum total advance must never be more than 43 degrees, otherwise engine damage might occur.

Test results: Test TAP and Range Rover 3.9