OK, can someone explain a couple of things about LPG to me please?
My belief has always been that on the whole an engine will produce more power and run more efficiently on super unleaded than normal, as it has a higher octane rating - typically 98RON vs 95RON. I know this is true of my BMW 330Ci, although also realise on smaller and older engines the improvements will be less significant and it does require a higher compression engine to make the most of it.
Anyway, following this train of thought and given that LPG is typically around 102-108 RON, why do we get a decrease in performance and economy when running cars on it, rather than an increase? My Range Rover has a single point injection system and I reckon loses around 15-20% power on LPG, and probably a similar decrease in economy. So where do the loses come from?
My only thought is because it is injected as a vapour it burns less efficiently? If this is the case, if you were to inject LPG as a liquid, would you see the improvements I would expect from the higher octane rating?
Finally, if I were to run the car solely on LPG (I try and give it some petrol to run on from time to time for better lubrication of the engine) and increase the compression, would I see a corresponding increase in performance and economy? I have no intention of doing this, just being theoretical and trying to understand it a bit more.
Cheers!
My belief has always been that on the whole an engine will produce more power and run more efficiently on super unleaded than normal, as it has a higher octane rating - typically 98RON vs 95RON. I know this is true of my BMW 330Ci, although also realise on smaller and older engines the improvements will be less significant and it does require a higher compression engine to make the most of it.
Anyway, following this train of thought and given that LPG is typically around 102-108 RON, why do we get a decrease in performance and economy when running cars on it, rather than an increase? My Range Rover has a single point injection system and I reckon loses around 15-20% power on LPG, and probably a similar decrease in economy. So where do the loses come from?
My only thought is because it is injected as a vapour it burns less efficiently? If this is the case, if you were to inject LPG as a liquid, would you see the improvements I would expect from the higher octane rating?
Finally, if I were to run the car solely on LPG (I try and give it some petrol to run on from time to time for better lubrication of the engine) and increase the compression, would I see a corresponding increase in performance and economy? I have no intention of doing this, just being theoretical and trying to understand it a bit more.
Cheers!