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I have until recently always had wrx's. I always run a knocklink on my engine. There have been many cases when I have filled up on optimax that my knocklink has indicated detonation. I used to not care too much about what fuel i was using except that it had to be 98 RON. After making a decision about 9 months ago not to use optimax again I ahve never had a problem with detonation, or atleast the knocklink didnt pick it up.

In short I think BP make an equal product to Optimax but they make it consistantly where shell dont.

I reckon BP Ultimate or Mobil 8000 (purple) is the goods. That has just been by hearsay but only good thing about Shell that i have herd is that it gets you more km's to the litre, but its through all additives which can cause greater knock. Thats just what ive herd so by no means take it as fact.

I'm not a fan of optimax, I tried it once or twice, neither of the 2 engines I've used it on liked it very much.

Nowadays I use Ultimate only but Mobil Synergy seems to be pretty decent stuff as well.

Word Of Mouth & Testing Fact.

Shell has alot of cleaning agents added too the mix. These additives make the engine poor poorly, but cleans your engines.

I had too have my fuel tested one day, I was using Shell, the tester commented that the optimax fuel tends too have lower oxygen rating, and for performance, mobil or bp where perferred.

Caltex Vortex isn't a bad mix either.

previously i had never really thought there was much difference between the 98ron fuels. however in my new gtr I have consistantly noticed the car doesnt run as well on optimax. initially i thought it was just a bad batch of fuel however i have nismo boost dials which consistantly dont peak as high when using optimax as compared to other fuels (vortex,ultimate or even extreme) and the car feels more sluggish on optimax.

Edited by marchGTR
For me:

Optimax is always cheaper but BP ultimate seems to give me better milage!

Since you are in Melbourne, due to refinery sharing they are both made at the Shell refinery at Geelong.

ie; there is no BP refinery in Victoria

:wave: cheers :(

Edited by Sydneykid
Since you are in Melbourne, due to refinery sharing they are both made at the Shell refinery at Geelong.

ie; there is no BP refinery in Victoria

;) cheers ;)

Everyone knows this.

Explain why on multiple occassions Shell reads a lower oxygen rating and slower lap times then other PULP ? I think you might find, and correct me if I'm wrong with proof, that each company also adds there own special mixes too the fuel at the same refinery.

Or... ring a marine shop, and ask them what fuels they suggest you use and WHY.....

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