Is lowering the octane in petrol reducing its quality?
No. Petrol is a sophisticated product that must meet a set of demanding performance requirements to satisfy performance expectations. Factors such as the drivability of the petrol (affected by the petrol vapour pressure and distillation), power, and cleanliness of the petrol, as well as the antiknock performance of the petrol, have an impact on the quality of the petrol. A vehicle manufacturer will specify a minimum octane number that is required by the vehicle to operate satisfactorily. Generally using a petrol with an octane rating higher than that required to prevent knock in an engine will not improve a vehicles performance. Shell ensures that the petrol specifications are such that the fuel is fit for purpose.
