[snip]
I read on another NG that Optimax is 98.5 RON equivalent, possibly the highest you can buy in the EU. Cars with antiknock sensors that adjust ignition timing may be able to get a bit more benefit from Optimax.
[snip]
I'm unclear over the column headings but my 2mpg gain is higher than either of those figures. On pure ecomony alone it still doesn't quite cost-in for me at todays prices. The other stated motoring benefits of either Ultimate or Optimax are hard to enumerate.
It definately isn't psycological but I'm not sure whether it's due to poor quality petrol (or the additives in it). The reason may have been the age of the petrol in my take at the time. When I filled up yesterday, Optimax this time, I felt a difference in performance and a difference in engine noise. I believe it's probably because my petrol was a few weeks old. It may be worth me trying supermarket petrol again some time.
One other question, is it possible for the difference to be almost instant, ie. within a few seconds of turning the key. I tend to find that I notice a difference almost instantly. It doesn't happen every time that I fill up but quite frequently.
With my car it did, It was nearly empty. Just a few gallons of unleaded in the tank, then I filled up with Ultimate, instant difference.
Dave
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.