what ron is UK optimax please

[zoog]

is it 98 or am i right in supsecting it is only 97 or so.....?



thanks

Adrian

 

[Gareth]

my understanding is that it is 99?

 

[Adams_16v]

i thought normal was 95 and optimax was 97. im probably wrong though lol

 

[rt172]

Dont know if it helps, but on Optimax pumps it says 98RON. Dunno what RON it is though....

 

[zoog]

but in my local stations it doesnt have it on the pumps thats why I asked!!

 

[Gareth]

The octane rating is a measure of a fuels resistance to knocking. Knock, also known as pinking, occurs during combustion when the fuel-air mixture explodes ahead of the flame front rather than burning smoothly, causing a knocking noise. Using a method established in 1929, petrol is rated on a scale of 0 - 100, and given a research octane number (RON). In the 1920s petrol has an octane rating of around 50 to 60. Today, Lead Replacement Petrol has a minimum octane of 97 RON, Unleaded of 95 RON, Super of 97 RON and in August 2001 Shell introduced Shell Optimax, which with an octane rating of 98 RON is the uks highest octane petrol.

http://www.shell.co.ukwww.shell.co.uk

Gaz

 

[Adams_16v]

Dont you know RON? top geezer

 

[Jonto]

Its 98.6 ron exactly

 

[Jonto]

unless, your station doesnt sell much of the stuff, and it sits in the tank for ages, in which case it degrades and is probably about 96 ron ! lol

 

[Turkish]

yup ive heard that too, super stays at its octane rating but optimax can degrade, i run my car on a mixture of both, sometimes super sometimes optimax, and i never ever use supermarket petrol

 

[mikeherts]

Which probably explains why my car feels pokier on super unleaded than it does on Optimax a lot of the time - dont see a lot of people using the Optimax pump and its most likely been sitting there for months!!

 

[Carlouk]

Yeah its the highest available in the uk when in prime condition. Its nearly 99! Ferrari recenty did a test running Schumachers F1 car on normal high street optimax and the lap times where practically the same!

 

[Jonto]

thats because F1s car cant use race fuel, that have to use normal high street stuff !

Optimax is basically normal unleaded enhance with chemicals etc, which is why it degrades, super unleaded is specically refined to be 97 ron.



I ran my scooby on super unleaded, not optimax



cheers

jonathan

 

[rt172]

Quote: Originally posted by Jonto on 21 April 2003


Optimax is basically normal unleaded enhance with chemicals etc, which is why it degrades, super unleaded is specically refined to be 97 ron.

Ah, is that why SUL always seems to be more expensive than Optimax?

 

[mikeherts]

Does anyone know the "shelf life" of Optimax then? After reading all this, I dont think Ill bother using it again! - I had been running a special cocktail mixture of 1 fill Optimax, then 1 fill SUL , but if it degrades that quickly, Id probably be better off sticking to SUL. That is unless I get the Optimax from motorway services where they are bound to have a fast turnaround of the stuff.

 

[Jonto]

I have a look on scooynet, this has been discussed in great depth, alot of owners put optimax in and there cars ran like a bag of sh*t, one guy actaully wrote to shell, and posted his reply.



cheers

jonathan

 

[Frosty]

Its about 40 days. In this time it must be refined, loaded for transport, transported (possibly stopping at many midpoints), placed into the forecourt tank, sold, and then used by you - the driver. I only ever fill up half way as a result.

 

[mikeherts]

So, is that 40 days from refinement to being back to 95 RON or is that 40 days from refinement to starting to lose its octane rating?

 

[zoog]

I noticed a definite improvement in performance and rengine response going form a tank of optimax to SUL, which is what set me wondering about the RON of optimax given the Cup demands 98 RON.

A mate who runs a 22B reckons optimax is good for turbos at risk of det, but SUL s the one to go for in normally aspirated engines........

 

[mikeherts]

I think 98RON is only a recommendation for the 2.0 16v engine used in the 172/Cup

I too notice the improvement when I go from Optimax to SUL, so I think Ill stick with Super in future. BP is my favourite!

 

[rustyarchs]

well when i sitch ma car off it tinks for bout 2 min after!!

i takeit thats pinking and that i should use optimax?

and is there any rason why my car does this and how i can stop it??

ps k reg 1.4 rt



thanks

 

[mikeherts]

Tinks? Sounds like metal cooling and contracting after a run.

Its not pinking - thats when the car is running and I believe it feels like the car is hesitating.

I would say that your car is fine on normal 95 RON unleaded. The engine will be set up for it and I believe you will need it set up differently to run on a higher octane fuel? Perhaps someone who knows more can shed some light on that.

 

[rt172]

Your engine wont pink when its turned off! The ticking is just the sound of metal cooling down and contracting.

Rhys

Edit - You beat me to it, Mike! I will add that if you want to stop the ticking, dont let the metal get warm. I would recommend packing your engine bay full of ice before starting the engine.

 

[mikeherts]

Only just

 

[rustyarchs]

il try that!

 

[Toine]

Your Clios ECU needs 500km or a refill to noticed the Octane change.

 

[TB11]

I wrote an email to shell who gave me a reply back (its on scoobynet somewhere).

basically, optimax is a refined fuel (ie its no less than 98.6 ron, no octane additives, just the normal detergents).

The reason that some scoobs det on optimax is that they are still set to run at 100+ ron fuel, now seeing that optimax is only 98.6 ron your down a bit and the ecu on the JDM cars are not as good for knock correction as uk cars thus problems (and the reason that JDM cars should also be run on octane booster!)

If your car is designed to run on a higher octane fuel then its best to run it on exactly what its meant to be run on, (it should state in the handbook about fuel).



Tony

 

[mikeherts]

So it doesnt deteriorate over time then?

 

[Frosty]

It starts to degrade after 40 days. How fast it does this is dependent on the usual variables i.e. temperature etc.