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Discussion Starter · #1 ·
Any of you guys tried the new shell optimax fuel.. I put a tank full in for the first time last weekend rather than the usual Super UL..

Does it make a difference or what... After further investigation on the shell website I find out why... It's running a higher RON Level than 98.. WoHey..!:D They don't exactly say what level it's running at, but they do say it's above 98...

HAve you guys tried this stuff...???

Malc:smokin:
 

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and how expensive is the bloody stuff !!

Mind you though, it's cheaper than a new set of forged pistons.

Gary.
MM
 

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Discussion Starter · #4 ·
Thanks

Thanks Dave

Interesting information..

Do Ferrari's work in a different way..?? Just I would of thought that they would suffer from detonation too??

You would think that they might notice something like this, or is it designed just for NA cars??

I have sent an e-mail to shell to see if they know about it and what response they give..

Thought it might be of interest.;)
 

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Optimax values

Malc,

When mainland Europe was forced over to unleaded gas only, my Ferrari mechanic explained leaded/unleaded and octane values as so:

Firstly the higher the octane value of a fuel the faster it burns.

Lead was a cheap way of increasing the octane value.

High performance engines such as Ferraris are tuned to use the highest-octane fuel available.

If you use a fuel with a lesser octane value than that for which the engine was tuned then the burn is incomplete as the exhaust valve starts to open thus compression and unburned fuel is lost into the exhaust manifold this is detonation or pinking.

The Nissan RB26DETT is designed to use 100 RON that’s about 94 octane in the US.

My old Ferrari was designed to use leaded 5 Star but was remapped to run on 98 RON that’s 93 octane US.

He also reckoned this thing that lead stopped valves sticking was BS because the same valves are used in engines that where intended to use unleaded fuel only as those using leaded fuel. No need to change heads just adjust the timing to suit the intended fuel.

I must say though this is one very good mechanics view.

Shell optimax is marketed in Germany as having a 99 RON and cleaning solvents that clean your engine as you drive.

Paul.
 

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Discussion Starter · #7 ·
Welth Of Knowledge

Thanks for that Paul

That being the case you would have thought the RB26 engine would love the new Optimax Fuel and you would'nt get the Detonation found in the Scooby's.. Would you?? Confused now..

Or is that Japanese 100 RON has got something else different about it?? Is the only way to check by using a Dyno??

Any thoughts

Malc:confused:
 

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Hello All

I use Esso SU which I belive is 97RON at around 80p/litre
This new Optimax is said to be 98+ at around 75p/litre, so what RON is super plus unleaded which costs around 85p/litre?

What is the best to use?

Regards
Orange.

(now the proud owner of a uk R34 with a middlehurst 400bhp upgrade, and oh yes a new daddy to a beautifull little girl on Friday)
 

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Orange,

If you want the full details check out;
http://212.67.202.137/~joss/forum/u...s=&threadid=502

The new Esso SU is now 98RON whereas most of the others are 97. You may also want to check whether you have a UK or Japanese chip in the car, the Jap ones are set to run at a higher RON level in which case you may want to use an addative (see another discussion string). Good luck, but some people are using Optimax and some not - a matter of personal chouice I guess until we learn otherwise.

John
 
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