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[Squatch]

I am sure that this has been asked before (possibly on numerous occasions) so apologies in advance. Is there any benefit to be gained from using Shell optimax/BP ultimate? Does the engine (2.5 V6) have a knock sensor that can sense such fuel and advance the timing accordingly? Do the additives in this fuel clean out muck and improve performance? Or is it a complete waste of money marketed at eejits like me?

[Kevin Wood]

The V6 does have a knock sensor. Opinions vary as to how much performance difference there is between regular and super.

My view is that unless the engine has very high compression or forced induction good quality 95 octane will probably allow enough ignition advance for best power on an efficient 4 valve combustion chamber. So, theoretically, there shouldn't be much if any difference.

As to the cleaning properties - It's marketing speak so who knows how it relates to the real world? I haven't experienced my engines getting particularly "dirty" on bog standard fuel.

I guess trying a tank or two is the best bet. If there is any ignition adjustment due to the (lack of) knock it could take a while before you notice a difference. Once you're tried it you can make your own mind up whether it's worth the extra cash.

I try to use Super in my kit car, but it has a shade over 11:1 compression on standard cast pistons and no knock control. It makes a noticeable difference on that engine but not on my 3.2 MV6.

Kevin

[TheBoy]

On my MV6 3.0l, I don't notice any difference of Optimax over standard Shell (though do between Asda/Tescos and 'branded' fuel).  I do not a slight improvement to performance and mpg on BP Ultimate petrol though, though not sure whether worth the extra...

[Martin_1962]

Supermarket fuel is definately worse.

A straight Tesco Shell comparison on 95 found that ont the Somerset levels I could gain 2 or 3 mpg and maintain top gear easier on a 2.0 towing a caravan.

I have not done the same test with the 2.6 as Propane is too cheap!

[mantahatch]

Hi
Have tried it in my V6 and it did not seam to make any difference. We allways use it in wife's Volvo S40 T4 (200bhp) and it seems to increase average mpg from 20.7 to 21.6.

HTH

Mike

[vesil]

Here in Finland we have 95, 98 and Shell´s V-Power 99 octane.
I think there is a noticable difference between 95 and 98 octane in the X30XE.
Car feels quicker and more economical on 98 octane, even though the 98 is more expensive.
I havent noticed a big difference between 98 and V-Power yet...

[mkaminski100]

As I have seen, "High Octane" petrol in UK is 97 usually with some cleaning addatives. In my opinion this it the reason why there isnt a big difference. I tried 100 octane ARAL petrol in Germaty once.There was no cleaning addatives and the car did more MPG and was accelerating better.
You can buy 91 oct petrol in Germany as well, and it's called "benzin"!! 95 is "Super Benzin"....
It's proven that any cleaning/boosting addative reduces power of ca 2%.

[Debs.]

I lived in Iowa and then California for many-years and both states have 87 RON and 91 RON std. at the pumps.....in Iowa they also have 10% Ethanol-enriched 95 RON.
I used all the major-brands of 95/91 & 87 RON fuels in my trucks and cars then (big and little engines) and did not ever notice much 'real-world' difference in performance/economy....or perhaps electronic fuel management is very good at disguising any shortcomings?

Would U.K branded-fuels be formulated very differently from the US types?

[Weds]

I am sure that this has been asked before (possibly on numerous occasions) so apologies in advance. Is there any benefit to be gained from using Shell optimax/BP ultimate? Does the engine (2.5 V6) have a knock sensor that can sense such fuel and advance the timing accordingly? Do the additives in this fuel clean out muck and improve performance? Or is it a complete waste of money marketed at eejits like me?

There a petrol station close to me in Maidstone that sells 102 octane fuel, I wonder how well that will go, would be tempted but it £2.64 (last time I looked) per litre

http://www.bp.com/faq.do?categoryId=9009089&contentId=7016946#1

[albitz]

i tried it in my 2.5 recently,didnt notice any difference in performance.i do have possible access to aviation fuel,i think i might try that the week before the car takes its last journey to mr scrappy.

[Grumpy]

i tried it in my 2.5 recently,didnt notice any difference in performance.i do have possible access to aviation fuel,i think i might try that the week before the car takes its last journey to mr scrappy.

I assume you mean AVGAS and not the kerosene based AVTUR.
Be aware that you will be taking it to the scrappy, or replacing
both Cats. The high octane rating achieved by AVGAS  is due
to the tetra ethyl lead additives.  

[Martin_1962]

If you want high octane convert to autogas

[albitz]

i tried it in my 2.5 recently,didnt notice any difference in performance.i do have possible access to aviation fuel,i think i might try that the week before the car takes its last journey to mr scrappy.

I assume you mean AVGAS and not the kerosene based AVTUR.
Be aware that you will be taking it to the scrappy, or replacing
both Cats. The high octane rating achieved by AVGAS  is due
to the tetra ethyl lead additives.  

yes it is avgas i was offered some to try in my bike to see if it gives it any more grunt

[Marie]

On my MV6 3.0l, I don't notice any difference of Optimax over standard Shell (though do between Asda/Tescos and 'branded' fuel).  I do not a slight improvement to performance and mpg on BP Ultimate petrol though, though not sure whether worth the extra...

the only difference is the pennies not in your pocket

[Entwood]

I tried to do a small comparison with the old beast (the 2.5) and these were my results :

On Optimax the car felt a little more responsive, slightly more "grunt" but that is highly subjective and may be wishful thinking

On long CONSTANT SPEED runs, especially with the 'van on the back, I got around 6%-10% BETTER fuel consumption, and as the price at the time was only 4% higher this seemed a good idea, better fuel consumption + more grunt = a happy towcar...   ; however, this all changed with a compulsory off motorway detour after Mr Plod closed the M6, non-constant driving the consumption was identical to normal fuel, so was effectively more expensive. I did try using cheap Sainsbury's stuff but the car just didn't seem to like it, so never finished the comparison.

HTH