What is the miles per gallon equivalant of natural gas compared to gasoline?
If the NGV is an original Equipment Manufacturer (OEM) model, it will have been designed to make the most of the excellent properties of Natural Gas – eg it will have a higher compression ratio than the petrol model and different ignition timing – and you could expect to see an improvement in performance and fuel consumption on an energy basis. This might be about 5% or more. Of course you might then drive faster, and not have any advantage. If the car has been converted from gasoline to NG and you can choose to run on either fuel (ie a bi-fuel vehicle) then it is not possible to make the most of the higher octane rating of the NG. In this case the change in fuel consumption will depend very much on the vehicle and engine design and on the conversion equipment used and how it is tuned. In this case you might expect an increase of possibly 5% in consumption. However the tune may be optimised to a particular power and speed range and if you can hit this you might get a small improvement.
