I was talking about this on track day.

The concensus (mostly BMW engines) is that there is a huge difference between 95 and 97 RON, the Optimax improvement is hard to tell.

I must say, the 100 RON Optimax in Germany really made the S2000 fly!

 

In my experience, there is only a marginal improvement in responsiveness/performance between Optimax and SUL 97 (although marginal a definate improvement though making the search for Optimax worth it), however, my S2000 runs so much smoother on Optimax it's like a different engine.

I also agree that the S2000 ignition timing is constantly advanced/retarded depending on the fuel and atmospheric conditions etc and an improvement between unleaded 95 and SUL 97/Optimax should be noticeable immediately - although you won't get the full benefit until running 'exclusively' on 97+ octane.

Can't wait for Tesco's SUL 99 to be made available in the South West...I've a Tescos a mile away from me and will definately give this a try!

Andy

 

Do the drivers really just pour in a bottle of something full of additives?

Or is this a tad simplistic?

 

BP Provide Sainsburys fuel. I know this as one of the girls in the office used to run a JS Petrol Station.
Don't know whether it is any different though.......

 

I put Tesco 99 SUL in today...........seemed fine though actually it was 1p moe than my local optimax - Ill stick to shell as I collect the points and so far have about

 

I think they then indulge in a few powerslides, just to stir it all up

Perhaps that's what was really going on in that Duel film

 

I put in several tanks of the old Esso "engine knock" during the wooly bollard tour.

Noticable difference in performance? None.

In fact half a tank of it has been sitting in the car for 3 weeks, used it all up today and put some optimax in.

Noticable difference in performance? None.

maybe I'm not sensitive enough but I could not tell the difference

 

I don't think you'r really going to notice it. Where you do notice it is when mapping. Its more of a big thing on turbo cars. When I was having the STi mapped, the chap was showing me the difference in timing you can pull with Optimax.

There is undoubtedly a difference.

MB

 

with Mark.

My Scoob ran like a bag of nails on 95RON, but was superb on optimax.

I use Esso SUL as there is a garage at the end of my road and it's cheaper. Occasionally use BP and Shell and have never noticed a difference except in my wallet