meester69

Well it's not any Golf it's a twin charger with a specific output of over 100bhp/litre.

I have the 2.0 R4 16v engine in my car which is merely turbocharged and it says to put the 99RON in, but I don't, and it's more than fast enough funnily.

Look at the numbers for fuel consumption:

Golf 1.4 TSI

95RON:
Esso: 33.5mpg
Tesco: 33.3mpg
Shell: 32.9mpg

99RON:
Tesco 33.6mpg
Shell: 33.6mpg

Now I don't know how they tested, but common sense would tell us that the Tesco, Shell and Esso 95RON fuels should come out the same, and a lot of people that like Shell's expensive marketing will tell you that Tesco fuel is terrible and they only use Shell. But the numbers here vary - 32.9mpg for the Shell is the lowest, and 33.5mpg for the Esso is the highest, so it's reasonable to assume that this is all just noise and this difference is statistically not significant.

In other words the difference between the 32.9mpg and 33.5mpg on the standard fuels is better explained by other differences (driving style, and so on), than by choice of fuels, since we would not expect Tesco fuel to be better than Shell.... So our assumption is Tesco, Esso and Shell petrols were all the same and the differences are not significant.

Given that this is so, and even disregarding the fact that the 33.6mpg for the premium fuels is barely any better than the standard fuels, and certainly not enough to offset the cost difference, our conclusion from here should be that there is no evidence, even in a twin charged engine, that you use less petrol by buying premium fuel.

The standard non-turbo engine does show slightly better fuel consumption, but it's only around 1% and certainly not enough to recoup the cost difference of typically 4-8%.

The numbers you quote are for bhp. I tend to feel that unless you are driving Le Mans 24 hours, the precise number of bhp to your wheels is of very little relevance. 2-4% improvement is not going to turn a Lada Riva into a Porsche 911.

Bottom line is this: the premium fuel will 100% certainly take more money out of your pockets but whether it's saving you any fuel (it won't save you any money, that's for sure!) or making your car perform any better is something of a mystery.

The bhp numbers look much more credible than the fuel consumption, but even here I'd like to know their methodology and see more testing results, perhaps with more different engines.

The Premium Diesel shows neither economy nor power improvement so you are certainly throwing money away on this.

Edit: more testing here - http://www.thorneymotorsport.co.uk/t...s_Update.shtml It gives fairly convincing evidence that the premium fuel gives more power than regular. Which is interesting enough.

Unfortunately for Shell, the Tesco premium fuel is rated higher than theirs....

So, back on topic: use premium fuel if you want to, not because it will save money (it certainly won't - it will cost more), but if you have a powerful car, it might give you more power (the Thorney Motorsport testing above is done with an M3, which gives an idea of the sort of vehicle)....

So none of this really makes the Shell Drivers Club much cop, considering Tesco fuel is just as good, and most importantly (and relevantly!), Tesco fuel earns more Avios!

Even if your local petrol station is Shell, and you always buy V-Power, so you are eligible for the V-Power Club, the online shopping kickbacks still are not as good as what you can get from Avios/BA directly.

Anyway, stick the card in your wallet, use it if you are in there for what ever reason, but for God's sake don't go out of your way for it....