"I'm always a bit suspicious about Optimax, because it's specified against BS EN 228 (95 octane regular unleaded) instead of BS 7800 (97 octane super unleaded). This suggests to me that it's bog-standard 95 octane with a cocktail of octane boosters and detergents added. No problem if you buy it from an outlet with a high turnover, so it's reasonably fresh, but I'd be a bit wary of getting it from somewhere out in the sticks - who knows what happens to the additives if the petrol is sitting in a storage tank for months on end?"

 

it goes off...

you are exactly correct!!!

95 ron has a better base fuel for adding octane to rather than 98 ron.

Leaded fuel is better still (4 star) but hard to get hold of and kills cats and o2 sensors.

Alex

 

Optimax is refined as 95 then boosters are added to up the ron rating where 97 sul is usually refined as 97ron with no use of additives

 

So what's better for power and engine.

95ron + octane booster to 97ron

97ron with no octane booster

 

Tesco 99RON!

 

...Tesco 99 ron + Octane booster.

 

i bought some super unleaded fuel from tescos and it was marked up at 97 ron not 99

 

http://www.greenergy.com/products/99_octane.html

 

RON is RON.... its a number.

Nither is "better" so to speak, just different.

Alex

 

More to the point, MON is a better rating to look at for forced induction vehicles, as it measures the fuels ability to resist knock at greater load. FWIW, I think the Tesco 99RON stuff has a higher MON rating than Optimax (but cannot remember the official optimax figures to be sure)

 

both values have little real world use... other than the higher the better.

 

cheers mate that site even tells you where to get it ,i got the 97 ron in trowbridge from a tesco garage ,if you spend so much in there store on food you get a 5p off every letter of fuel how good is that
matt

 

if you spend at least £50 in their store on food you get a 5p off every litre of fuel