I am convinced that my car runs a lot worse on BP ultimate compared to optimax so I have been filling up at shell, I am convinced it runs better on that but also does far less MPG.

so I emptied the car pretty much and filled up with tesco 99 RON
and I swear it runs a lot smoother and less noisey and its not kangeroed yet which is nice

I think from 3500RPMish+ it seems to pull more I think it maybe faster too but its smoother and less noisey so i am not realising it

am I tripping and imagining this all ? my car is an import I read somewhere imports maybe setup for higher octane fuels

 

I've been told the import has a thinner HG and therefore higher compression.

It'll be set for 100RON .. Tesco's is the highest, Optimax has better dett provention (but not being able to advance the timing and with no boost it a bit pointless) and BP is all green and dolphin friendly.

 

5th gear done a report a few episodes ago stating optimax was alot better then bp ultimate. and i think last weeks auto express done a similar test. bp ultimate made cars lose power!

 

you will prob need a couple of tanks to let the car adjust.

And this Kangerooing thing.. i have never had it.. prob cause i drive it right

 

i had it for the first time on the tunnel run the other night. constant vtec then slow city driving!

 

I wish people would stop posting about fuel

Ultimate is not trying to compete with Optimax in terms of ability to extract power, its advantage is aimed at improving engine cleanliness and MPG.

I imagine maybe 2 or 3, maybe 5 bhp max could be extraced from fuel differences (SUL) on a car like the S.

The way I like to think of whether one can notice the difference is to think of the power sapped by putting the aircon on. Maybe 5-8 or so - now ask yourself if you would notice that if you didnt know it was running or not??? Maybe you would if you instantly put it on or off, but not between blended tanks of fuel over time!

Turbo car I would be more concerned - average bhp N/A car like the S - im not fussed what SUL I put in it

MB

 

I use the air con as a retarder brake, as a wagon driver uses his exhaust brake!

You can really feel it on overrun between 3-4K, when you hit the button.

That's what about 5 BHP feels like!

The car runs beautifully on 100 Ron! Buy German Optimax, I say.

 

i did a couple of tanks of ultimate in sucession and on those got about 1 mpg less than with optimax on similar journey's

currenty on 2nd tank of tesco 99 and dont notice any difference in performance compared with optimax.

 

True Nick, but you got to look at it in terms of acceleration rather than drag on the drivetrain (as I know you know)

I still maintain that its almost imposible to ell the difference between one SUL and another. The car can behave differently due to so many variables, such as ambients (affecting the ECU) or the quality of the fuel from the invividual petrol station. Optimax has been proven to "go off"

Just stick with what you're happy with I guess, but I dont care whether its BP or shell. And I work for one of those!

MB

 

I only use Tesco 99 and optimax if i can't get to tesco. Its all the same really. I think optimax is 97.6 RON - never noticed a difference, except a tank of 95 RON JET fuel I had to put in - that was rubbish!