I think there is a benefit to be had from using good quality higher octane fuel. Regardless of what the manufacturer might recommended in terms of the number of degrees before TDC, the best ignition timing for any engine is as advanced as you can get it without the engine pinking. Higher octane fuels burn in a more controlled manner, and so allow for the ignition timing to be further advanced than lower octane fuels which tend to produce more of an uncontrolled explosion. The result is better and cleaner burning, better fuel economy and more power.

Personally I leave supermarket fuel well alone. It might be a couple of pence per litre cheaper, but that's not because the supermarket wants to do us a favour. It's cheaper because the final product is not as good as the branded stuff.

I use supermarket fuel all the time because it's fresher - there may be a difference in the additive packages but until someone publishes the constituents of their package I'll ignore the PR/marketing hype.

I've never had a fuel related issue in 40+years despite running most of the cars long mileages - and driving all of them hard at times.

+1

Could have written that myself.

Only time we use a "premium" brand is when we go on holiday, the nearest Tesco is 30 miles away and I don't think it makes economic sense to drive that far to save about 4 or 5 pence a litre.

But the rest of the year its Tesco or Asda just like it has been since Asda opened in town in the mid 80's.

All motoring journalists recommend the product they get the best launch holiday from or some other form of financial incentive. I remember when the new Vectra was launched in about 2004/5. They were all saying that finally the Mondeo had met its match. 6 months later it was a 2 star car and not worth considering. What Car recommend Tesco fuel, could they possibly get advertising revenue from the constant plug.

I have been using suermarket fuel pretty well since they have been selling it and for hundreds of thousands of miles, I have run diesels for most of this time and have had them last for 200-300k miles and give good economy, so I don't see a problem.