Fuels... worth the extra?

[feef]

Has anyone got, come-across or bookmarked any PROPER scientific, or technical test (read not anecdotal) reports regarding the supposed improved performance/efficiency of such fuels as BP Ultimate, esso Extreme (i think it's called) or the ubiquitous Shell Optimax.

Reading the fuel manf's blurb doesn't give any scientific explanations for these supposed improvements.. only that "detergentsa are used" or it's a "high density" fuel... there's no real correlating information regarding what these things actually do, nor how they do it..

Anyone???

a
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[dainesefreak]

No scientific evidence that I know of myself other than RiDE or some such magazine testing bikes run on Optimax and seeing an improvement in BHP.

In fact the article thread is here;

https://www.bikechatforums.com/viewtopic.php?t=39014&start=0&postdays=0&postorder=asc&highlight=optimax

[Will87]

Alot is to do with the octane rating and then only with engines that have sensors and adjust to the new fuel characteristics.

[mchaggis]

If a fuel is simply better because it has a higher octane rating, unless your engine has auto-advance ignition, it won't take any benefit from it. If it has detergents in, it won't do jack to the combustion, but will probably help maintain the performance of the fuel injection/ carburettors, as well as possibly helping to keep the valves and head clear of crap, though most of that is burnt off.

If it has auto-advance and knock sensing, it will advance the ignition up to just before the point of knock, which will greatly increase the power output as the increase in combustion pressure will more closely match the increase in the normal cylinder pressure.

The main cause of soot is the fuel which does not burn in the cylinder having quenched itself on the walls or in the gap between the piston and the cylinder. Fancy fuels may help to reduce soot and carbon buildups, perhaps lowering the risk of borked piston rings. They might also try and claim that their fuels improve the performance of the cat. converter by not getting carbon clogged.

Most of what the fancy fuels do is superflous imo, with the only definate performance gain being in engines tuned to take advantage of a higher octane rating fuel, or those which can alter their own ignition timing to match the fuel. Obviously, increased compression ratios would do even more, but those are entirely fixed on the whole.

Variable port injection, variable ignition timing, exhaust gas recirculation and catalytic converters are probably the greatest things controlling the 'cleanliness' of engines.

If we had a perfect world, we'd have infinitely variable valve timing available outside of Lotus experimental engines. The hope is that EGR can remove a lot of the need for cat. converters, but I doubt we'll be getting shot of them for a while. Another thing which would be nice would be the freedom to tune exhausts correctly without having to put recirculation equipment, cat. converters and silencers in the way.

In summary, worth the extra? Not really unless you've got specific pieces of kit.
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[feef]

[pipnet11]

What mchaggis said. If you havnt got a highly tuned engine that can adapt itself to the different fuel then there is no point.
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[mattsmith95]

As mentioned in previous posts on the subject...

With hand on heart I can say that YES these fuels like Ultimate, supreme and optimax are worth the extra pennies.

The problem is that you have to work out what fuel your bike likes, some of the superfuels don't make an impact on some bikes.

I haven't got or seen any test results, I only go with the experience I've had and because of my job I can say that these fuels are worth it.

However, petrol treatments like good old Redex is still a great option.

[Kickstart]

[TOM M]

to be honest ive used most fuels im me bike / car and cant really notice a difference between any of them, although me rs doesnt like ESSO petrol much. Ive also noticed that TESCO petrol seems to last an awful lot longer than anything else, i seem to get more miles per tank
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[feef]