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Discussion Starter #1 (Edited)
A good article in CCC this month about Shell Optimax. They've tested it on a Vectra GSi (ask Phil for more details:D ). Aside from getting an additional 5.1% on speed it also helps clean the engine due to an eaerlier ignition.

Note sure how balanced this piece of journalism is. Any thoughts?

Let's hope a few of the other companies follow suit and start producing stuff that doesn't [email protected] up the engine.:)
 

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5.1% percent increase over standard unleaded, but who on here uses that ??

I want to know how it compares to '97RON before adding it to my expensive engine.
 

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Discussion Starter #3
The bit I liked best was about the way it helps keep the engine clean(ish).

Most cars uignite the full at the optimum point for efficiency (ie. slightly late) too late and this causes knocking. To prevent this ECUs may retard the ignition which lowers performance. Optimax allows for earlier ignition (not sure what this does to the engine).

Shell also suggest it will help remove/keep down any deposits on valves etc. I'm not sure how this works but I guess its worth investigating at least.
 

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shell

I've filled up with it a few times now and my car's loving it, as it's only available at selected shell stations I have to drive to the next town but it's worth it. It's 98+ octane and anything that takes you towards 100 has got to be a good thing, besides it's much better that running octane booster.
 

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Just on second tank full - does seem more
responsive, after reading that link though, I
am a bit worried about what's going on inside
my engine!
 

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Interesting .. but

What's NF Blowdog?

And what's the compression ratio of a scooby at 1.3 bar? but it sounds like (on the evidence of 3 tanks, one car and knocklink) maybe optimax's other ingredients much it up...
 

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Yeah, just read it and I am a bit worried. Who wants to prove what it is like at the Dyno Day? May put Esso in instead now!
 

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Discussion Starter #10 (Edited)
Hmmmmm, some interesting observations.

Just for the record Esso have changed from 97 RON to 98 RON for SUL, so that probably looks like a better bet at the moment.

Guess I'll put a tiger in my tank to match the animal behind the wheel :D

John
 

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I normally use Esso SUL with one tub of Millers Octane Plus which, in everyday driving, does not lead to any detonation worth worrying about. Track work is quite different and extra fuel and less timing is needed normally to stop det. The Apexi Power FC displays det on a 0 - 100 scale. Very occasionally, I might get a reading of around 30 or 40 if she's pushed really hard on the road.

I'm on my second tank of Optimax now. The first tank I tried on it's own without OB and det did seem to increase slightly over Esso SUL with OB particularly when she was warming up, may be 20 - 25 while pootling about which isn't a cause for concern but is interesting. The second tank I have put OB in and det whilst warming up still seems to be more than normal although I've not pushed her much when hot. I'll post again when I have.

Peter.
 

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I've just put my first tank of optimax in and have to admin it runs better when cold and feels smoother, but I am also now concerned about the possibility of det at the top end as you generally can't 'feel' it in the car when its at the high end of the rev range. :( I think I may get some esso for the dyno day if I can find one nearby which does 98 sul.
 

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Hmm at £8/£13 a bottle (is that for 1 tankful ?) seems a bit dear when compared to Millers at £2 a bottle.

How many tanks of fuel does NF do ?
 

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Discussion Starter #17
Cem,

Just ordered some NF Booster, will let you know how I get on. Guess I'll be avoiding Shell Optimax for the time being - tooooooo scary!

John
 

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I try to use SUL but sometimes you cant get it & dont have enough bottle to carry on to the next petrol station. This happened last week in Nottingham 160 miles from home so i filled up just 2get home (on the common stuff) but the car went better than ever what does the 2? extra oct. do ? & are we sure of what goes in the tank anyway?

I'm not paranoid but....

Weston

Ps Phoned up 2Get the car valleted the quote was £25 but it took him longer than expected & he demanded £30 it just makes me think I should get the car done more often ....
 
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