"Prodrive's Warwickshire test facility near Kenilworth was used to check out the company's claims -- which are undetailed -- that the petrol offers more grunt than standard petrol. Just how much more, Owens wouldn't say. "Testing costs a lot and there's no baseline petrol to compare it to as they're all different," he said. "It's just better."
This sounded amazingly vague, so with BS detectors on full alert, we thraped a pair of Subaru Imprezas :roll: and a pair of Ford Fiesta STs :shock: round the test track. One of the Scoobies was filled with 97RON fuel -- the minimum recommended by Subaru -- and the other with Tesco 99, while one of the STs was brimmed with 95RON, the other with Tesco 99.
It was a blind test -- we didn't know which car had which fuel, yet your reporter was able to distinguish between them by their performance alone.
The main effect was increased low-down torque. While we had no measuring equipment, the 99-filled Fiesta would spin its front wheels exiting corners under power at the same point on the lap where the other didn't; it also felt more torquey. With the Scoobies, the difference was less marked -- as you'd expect given the lesser difference between the two fuels in the two cars. However, it did feel more perky in the lower end of the rev range, before the turbo kicked in, and we were consistently travelling slightly more quickly at the end of the main straight"
The conclusion you’d have to draw is that a high performance car will experience less improvement using Tesco 99 as it's more likely to be running on a higher octane fuel anyway. But all modern cars with an anti-knock sensor and electronic ignition management should be able to benefit from it, according to Owens, not least because it also contains engine cleaning agents similar to those in Optimax.