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Fuel (High Octane)..... Which ones to avoid ????

Discussion in 'Bling and Appearance' at netrider.net.au started by paulm_collins, Jun 13, 2007.

  1. Hi all !



    Ive had my new bike for 3 weeks now and was a little unsure about the fuel.

    When i picked up the bike, the sales guy told me to avoid Shell and Caltex, and that Mobil and BP are probably the better two to use.

    I filled up from Mobil when i first got the bike and it was running like a dream. As there isnt a Mobil near where I live, I then started to use BP Ultimate about a week later. I dont know whether its a coincidence but it seems to have started running a bit rougher after I switched to BP Ultimate.

    Does anyone have any views on this ?
     
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  2. I've alwayed used BP ultimate. I am unsure of the difference in Mobil and BP though. I have used Shell premium once(I was running out of fuel at the time). At the time it didnt seem to run differently than BP ultimate. I hardly noticed any difference.

    Im kinda looking forward to reading ppls views as well since I still dont know alot about petrol/fuel.
     
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  3. :popcorn:


    I have tried them all and for my bike plain old el cheapo unleaded runs best.
     
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  4. I have a Triumph Sprint ST and, as its fuel injected, I was told that i have to use the high octane fuel.
     
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  5. If the bike's fuel injected it should run on anything above whatever the manufacturer gives as the minimum octane rating. If it's carburetted it'll run best on the octane rating it's designed to run on (should be in the owners manual). Only fuel to be particularly wary of is Shell V-power Racing or any other ethanol blend as no Japanese manufacturer recommends using ethanol in their bikes (modern European bikes should be fine though).
     
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  6. Every bike is different. Some respond to higher octane fuel, others don't. Many don't like the 98s because of all the additives. The most trouble seems to come from Optimax, but some people swear by it.

    I run 91 on dear days and 95 on cheap days, because the bike runs marginally better on it. The odd tank of 98, for cleaning purposes, but never Optimax and it run shit on it.

    Funny thing is I had a water cooled gsxr11 for a while and I got better economy out of the 91s than the 95s which is the complete opposite to what I get now on the air coolled gsxr.

    So yeah, every bike is different.
     
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  7. I agree with JD on this. It will depend on the bike and it's fuel system, but generally, if it's a highly tuned sports bike (even a 250) it should run a bit better on high octane. I avoid ethanol mixes with my bike because I have no information on whether it is harmful or not.
    BP Ultimate seems to make it run a bit rougher than V-power or Caltex, but not enough to worry me. The old Shell Optimax used to do the same thing.
     
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  8. My FZR250 was never tuned to run on premium 98 octane from the factory in Japan. In fact a lot of others on the FZR forums find that changing to premium makes for an over rich mixture and has flat spots at certain rpm.
     
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  9. I use standard unleaded in my GSR as that is what Suzuki recomends. I have tried most of the premium fuels but they make no differance to power or economy. Use what the owners manual tells you to use and see how it goes. If it runs better on premium though use that.
     
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  10. You are not cleaning it by running high octane fuel. Sorry, but thats a fact. The higher the octane, the less likely the fuel is to burn. If your engine is only tuned for 91, then running anything more in it will not burn as completely and leave carbon deposits and you will lose more energy.

    "but it makes the engine sound like its struggling less" The effect is like leaving your choke on a little bit, makes it easier to burn some, but not all the fuel.

    "but higher octane fuel is more expensive and is thus better quality" WRONG. Fuel does not come as 100% 2,2,4-trimethylpentane (the real name for octane as known in fuel). Fuel is a mix of octane isomers and heptane isomers. Fuel has additives to it which increase the RON. The higher the wanted RON, the more exotic the additives have to be.

    Bah. You will get the best performance from running the recommended RON fuel, you will also save the most money this way. Performance doesn't come on tap, yes higher octane fuel can render higher performance BUT, you need to tell your bike to take advantage. On older engines this is accomplished by advancing the timing and leaning out the mix. If you own a new bike, you are doing nothing but wasting money running over-high octane fuels. Older bikes come under more discretion as carbon buildup increases the compression slightly.

    Read this article; http://www.automedia.com/High/Octane/Fuel/ccr20050501ok/1 Take note it is an american article, and their octane rating system differs to ours and japans. 87octane in america is 91 here.
     
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  11. It's not the octane rating that I believe is cleaning it, it's the additives. Perhaps I should have been clearer as I mainly believe it's giving the carbies a bit of a clean.

    I've heard this argument about "the manufactures spec is best" before. This might be a good rule of thumb for cars and it's certainly a good starting point for bikes, but the reality is that no bikes are made for Australia. Rather they are re-tuned to pass our emission tests. So not only is it possible they will run better on better fuel, it is likely.

    Keep in mind I don't run a standard exhaust, filters or jetting (as do many people) so the manufactures recommendations hardly apply, with regard to air:fuel ratios, which is what you a intermating with the incomplete combustion reference.

    I certainly get better fuel economy and it's certainly nicer on the engine in summer.
     
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  12. I've tried all on by Ducati 748 and the higher the octaine, the better my mileage and the better the bike feels.

    I'll still use lower octane if its heaps cheaper or I'm out somewhere that only has 91
     
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  13. My manual says 91+. The RF runs ok on 91 but better on 95 and shitfull on 98. 95 is best on a trip but commuting 91 is good enough for me.
     
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  14. Unless of course the bike has fuel injection and a knock sensor - and will therefore adjust automatically to take advantage of a higher octane fuel.
     
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  15. My bike likes shell 95. More so then any BP.
    I was told that caltex is crap, from one of the servo guys that rides bikes. personally cant tell the difference between it and BP.
     
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  16. I tried putting different fuel in my bike the other day. I put in 91 with abt a third of a tank left of bp ultimate. I noticed that my bike wont run very well(feeling). It likes 98 alot more...
     
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  17. Frickendevil – “You are not cleaning it by running high octane fuel. Sorry, but thats a fact. The higher the octane, the less likely the fuel is to burn. If your engine is only tuned for 91, then running anything more in it will not burn as completely and leave carbon deposits and you will lose more energy.â€


    Not quite. Higher octane fuel burns slower. How completely it burns is dependant on many factors. For example modern fuel injected engines have oxygen sensors in the exhaust and the amount of fuel injected and ignition timing will be adjusted to ensure complete combustion.


    Frickendevil – "but higher octane fuel is more expensive and is thus better quality" WRONG. Fuel does not come as 100% 2,2,4-trimethylpentane (the real name for octane as known in fuel). Fuel is a mix of octane isomers and heptane isomers. Fuel has additives to it which increase the RON. The higher the wanted RON, the more exotic the additives have to be.â€


    In reality fuel of any grade is a mixture of chemical fractions, including octane (8 carbon chain) but also anything else that boiled out of the dinosaur oil at the boiling temperature used in manufacture with carbon numbers from 4 to 12. Octane rating in itself is an empirical measurement which, despite the name has nothing to do with the amount of any one chemical fraction in the fuel. The term "octane" comes from using pure iso octane (RON = 100) and iso heptane (RON=0) and mixtures in between, as the reference fuel in the comparative testing environment hence Research Octane Rating or RON. For example pure ethanol, has an RON of 129, hence the “octane rating of 95 for a mixture of 10% ethanol in 90% unleaded (RON=91).


    Frickendevil – “If you own a new bike, you are doing nothing but wasting money running over-high octane fuels.â€


    Maybe. In general your correct but both my ’98 VFR800 and my 2001 Commodore get around 10% better consumption on a trip from 98 RON fuel, more than enough to compensate for the additional cost. However there is no improvement around town and my bike takes two pushes of the starter in winter because of the slower burning fuel.


    Frickendevil –“Older bikes come under more discretion as carbon buildup increases the compression slightly.â€


    Major issue with older bikes is the lack of sophistication of the engine management system and therefore ability to measure and adjust operating conditions.
     
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  18. I ran my old VTR firestorm on shell optimax (now V-power) and it clogged the plugs in a matter of days. And ran like crap.

    Shell Optimax (V-power) is a thick blend fuel an the smaller engines can not burn it fast enough.

    I switched to BP ultimate and the bike ran better after a tank or 2 with a can of fuel/carby cleaner. Never missed a beat again.

    If I cant get Ultimate I use Mobil premium or Caltex Vortex.

    Run the CBR on ultimate and has been fine.
     
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  19. Good point. Not all 98 octane fuels are the same. Both Optimax (now V-power) and Mobil 8000 are not only high octane (RON=98) fuels but are higher density fuels than say BP Ultimate or Caltex Vortex (both also 98 RON fuels).

    Firestorms use a (large) carby rather than fuel injection and cant compensate for the higher density of those fuels - so the engine runs rich.

    Burn rate has nothing to do with engine capacity. It is amongst other things, influenced by cylinder dimensions and head design however.
     
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  20. Unless your bike has an O2 sensor, it won't adjust for the extra density either. Fuel injection doesn't magically know you've put in higher density fuel.

    And, anyway, even things with an O2 sensor aren't going to change the fuelling at high revs and almost to completely full throttle.

    As for "knock sensors giving you advantages when higher octane fuel is present", that's somehwat wrong, too. Things don't turn up the wick unless they're knocking - they have a base timing setting, and if they detect knocking, then you'll find that the timing is retarded back. It's not advanced until it knocks, it's simply retarded to prevent engine damage.

    You run the fuel that your bike is manufactured to run. Lots of things are happy on 91 RON, or 95 is sufficient. Hell, I lived in Tassie, and I only had the choice of 91 or 95, and the bike was just fine.

    That doesn't actually adress the original poster's question." Of the 4 98 RON fuels, which one to use"?
    People love to say that, say, Shell destroys your engine. Heard it alot. Never killed any of my engines. Neither have BP, or Caltex, or Mobil. Some things will respond better to one fuel or the other, it depends, and you only really know by trying. Even then, most people have placebo effects, they think one fuel is better, but can't provide any kind of hard data.

    I have hard economy data, and some data analysis, and at least in my experience, my bike is just as economical running on BP Ultimate as it is on Optimax. Would have tried the others, but, I live closer to BP's and Shells, so they're the first choices to test.

    If your bike runs like arse on any fuel, perhaps it's a bad batch (go to another servo and try it again). If it keeps doing it, try something different.
     
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