shell premium v mobil premium

[VR28LT]

On the pump it will say BP Ultimate ( blue pump )

[R36FTW]

I used to be a die hard fan of Shell Optimax and later on when they changed to the name V-Power as there used to be a couple of servos in Sydney that sold V-Power racing which had an RON 100 (not sure if it is still sold?) the last Shell off the princess hwy just before Sutherland where the turn off to Wollongong . But ever since i got my VR6 i noticed it runs heaps better on Mobil 8000 or Caltex Vortex 98 ( not 2 be confused with Caltex Vortex which is just RON 95 ) to bad out where i live i have a BP down the road and a Shell on the opposite direction and the closet Mobil or Caltex is some time away .

Anecdotal reports from tuners back where I used to live I told me about all the problems caused but shell Optimax fuel, especially with bikes. Some reported total engine failure believed to be Optimax related. There were so many issues caused by it (cars included) that Shell pulled it off the market. Apparently from analysis they were using butane to raise the octane rating, which was causing damage to certain plastics and rubber components in the fuel delivery systems of vehicles, and that after a couple of days the butane came out of solution, remaining as gas in the tank - people also noticed a lot of vapour pressure escaping when undoing the petrol cap to refill again - this was the butane escaping. The corollary to that is the octane rating of the remaining butane-less fuel was lower, causing detonation issues in cars tuned with maximum timing on 98, and general power loss in cars tuned with less aggressive timing maps. This was most noticeable when cars were in for a tune and mods - do a baseline dyno run, leave the car in the garage for a day or so while parts arrived, put it back on the same dyno and it would have ~20HP less than the previous run although nothing had changed. Those vehicles running BP Ultimate were consistent for over a week.

Now shell have released V-Power, which may or may not be the same formulation under a different name. Some guys think its great, others are indifferent and some, because Optimax left a very bad impression on a lot of people, wont use it at all.

Seat of the pants dyno testing of fuels though is about as unscientific as you can get though. Do some actual dyno runs with multiple tanks of fuel if you want some conclusive evidence.

[Sword_Dude]

Hi all,

I note that a lot of the comments on this thread are pretty old and was wondering if there are any updates due to changes in the marketplace.

Now that Mobil has pretty much left the scene what are your opinions on the best 98 RON fuel. I have only filled up once (with Caltex Vortex 98RON) and haven't noticed any real difference at this stage from whatever the car came with.

I noticed someone said the best fuel to get is generally the one from your nearest refinery, I think we have a Caltex refinery here in Brisvegas so does that really make a difference.

Also as I only do 120-150km per week am I going to have issues with the fuel going off (ie additives breaking down) and should that influence my fuel buying decisions or should I just buy half a tank every fortnight rather than a full tank once a month?

cheerio

[RSOK]

Mobil fuels have not left the scene, they have simply exited the retailing sector. The 7-Eleven brand bought out most Mobil retail sites (ie petrol stations) but it's still Mobil supplying the fuel to them (I believe that they're contracted to supply fuel to 7-Eleven for the next 5 years or so.) I'm still filling up with 98RON at my local 7-Eleven as a result (although locally my only other choice is a Caltex/Woolworths servo and I refuse to support the Woolies juggernaut).

As for your low mileage, I'm not sure fuel 'going off' is a major issue but if it were me I'd probably buy only what I need for the week, keeping my tank at least a quarter full. That way you get 'fresh' fuel each week (or even fortnight would do) and avoid the stagnation.