The cheaper petrol..eg supermarket petrol..doesn't have the quality of additives in it..compared to Shell Nitro. ..some havn't got any. And the storage facilities of some of the actual petrol stations ( AT THE SUPERMARKETS ) are suspect ! eg I had a relation who was a Manger at a large morrisions p station..they often had water in the storage tanks..made worse by the 5% ethanol in ALL petrol now ! Some customers complained..problems after filling up...always..denied..don't know what you mean ..was the stock reply to customers !
They want to up the Ethanol up to E10 before to long i was reading about the other day ! That will be fun !! Let's hope ..there is a mass motorists protest this time.
One point of interest that came up, last octane chat !! , ..was that all the Addititves are added by the Petrol Tanker driver...after/before ..he fills up with the petrol from the refinery !
Harry
Also..Shell Nitro has beaten all the other petrols..in several proper tests ! ( all on web )
p.s. bad spelling day today !!