UPDATED NOVEMBER 2015: Motorists can be forgiven for being confused about the fuels available and what their car needs. There are five types of petrol now available (standard unleaded, 95 premium, 98 ultra premium, E10 and E85) as well as Diesel and LPG.
This blog is to help clear up the confusion about which fuels are the best to use. We begin with premium unleaded.
Premium Fuels – is there a benefit?
Petrol vehicles are designed for a specific octane fuel and normally do not benefit from using higher octane fuel.
If the manual says you can use more than one type of petrol or blend, you may get the advantage of reduced fuel consumption (but only if your vehicle’s engine automatically adjusts its parameters to take advantage of higher octane). Conversely, you may be able to save money by using a lower octane fuel, if the manufacturer states the vehicle will run normally on it.
As a rule of thumb:
- 95 premium can give around 4% lower fuel consumption than 91, assuming the engine computer adjusts to take advantage of the octane difference.
- 98 might give 3% reduction over 95, again assuming the computer adjusts the engine parameters.
The overriding recommendation is to consult the owner’s manual for your vehicle and use fuel of the octane listed. Some motorists report lower fuel consumption using higher octane fuel. If you wish to check this for yourself, be sure to record your fuel consumption for at least 10 tanks before you make the change, so you have a good baseline.
Try and check your baseline under normal conditions – if you have an unusual country trip in the middle of your test period, for instance, it will result in atypical figures.
Conversely, if your driving is normally on highways, a week of city driving will bias your figures. Then change to the higher octane fuel and do a check for the next 10 tank fills and compare the figures. If the savings from any reduced fuel consumption are outweighed by the extra cost of the premium fuel, it is obviously not economically sensible to use the higher octane.
In our next blog, we’ll look at ethanol in petrol (E85 and E10).
Which premium unleaded fuel do you find the most efficient and cost effective?