super unleaded? good/bad

[bigbigboy88]

does anyone put super unleaded in their bike? i've heard that if you put it in they dont run as good as the timing is set for normal unleaded? i have a yam 600, and thinking about putting shell optimax in it, has anyone got any ideas on this matter cheers mat

[Stevo]

Yep i always try to use super unleaded in my ZX6R. It reccomends a min of 95RON, and super unleaded is 97RON, so i prefer to fill with super whenever possible. The ZX6R has nearly a 13:1 compression ratio, so i reckon that normal unleaded must be the absolute minimum that it would tolerate. I dont worry about paying a few pence extra for super, as it never costs more than a tenner to fill anyway, but if i cant get super when i need to fill up then i just put some normal unleaded in, until i see an Esso station.

[Guest]

is there no down sides to it then like engine running too hot or valves burning out?

[Stevo]

I cant see that using a higher octance fuel could make you run hotter, or burn out valves. On a four stroke its usaully having a weak mixture at high revs that causes valves to burn out. Many early GSXR600's with race cans were prone to that, but then thats what a jet kit is for!
Theres some stories that i have heard, either that or old wives tales. Such as people say that you should run kawasakis like mine on mineral oil for the first 20k, to prevent any oil consumpstion, and give best power. But i have put Pro4 oil in my bike as a 14500 rpm superbike engine in my opinion needs somthing better than mineral oil! A m8 of a m8 reckons that he has worn his R6 out by using fully synth oil, and cos he gives it a right hammering, that his valves could drop, so he was going to get a new head from a crashed bike for it. Sounds dubious to me!

[Dan]

i always use supper i wouldnt reck your egine, just goves u a higher octane level giving u a little more power, not much though

[Guest]

Do you get shell optimax in your country, if so avoid using it! unless you like to burn holes in your pistons

[Guest]

thats what i'm using shell optimax whats this about burmning holes in the piston?

[feef]

There's some bollox out there about octane ratings...

Petrol is made up of Octane and Heptane (and a few other lighter hydrocarbons) the Octane rating the is the percentage of Octane in the fuel, so octane rating 98 is 98% ocatane 2% Heptane (and others) Octane can be comspressed more before it spontaneously combusts, Heptane less so.

in an Ordinary engine, running ordinary compression ratios, Higher Octane rating fuel is irrelevant, as it's being ignited before it reaches it's optimum point of compression, and so unburnt fuel is getting passed into the exhaust (hence the Eggy smell in Cats on cars, unburnt fuel getting turned into Hydrogen Sulphide)

A lower octane rating for machines with a lower compression ratio (2 strokes) works fine.. Most of the Higher Octane = More power is crap meant to line the oil companies pockets.

Have a look for some more info..

https://theserviceadvisor.com/octane.htm

https://www.howstuffworks.com/question90.htm

https://www.ftc.gov/bcp/conline/pubs/autos/octane.htm
(I know the links are car based, but the science is the same)

Irronically, with the advent of Cats on cars, they have become less efficient than if they had continued using leaded fuel. As Leaded fuel could handle higher compression before igniting, "lean burn" technology meant you could have artificially high "ocatane" ratings by addding Ethyl and Lead. Higher compression meant cleaner burning.

FOr Unleaded fuel to work, it ignites at a lower compression, so the engine is less efficient, as you need more fuel in the cylinder to get the same power,

One of tyhe biggest advocates of Cats was a company in CAlifornia that had designed and patened CAT technology using US govermnment grants, so it was in both Their interest and the US gov's to promote Cat usage. The fact that most cats use heavy metals, mined from third world contries, and the pollution caused by their extraction is worse than ANY amount of cars seems to have excaped their notice.
<Rant mode off>

I did a study of this when I was at uni working on engine design.

a
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[Guest]

I dont know if its as much a problem for road bikes, but most people I know who race bikes do not use optimax, It has cuased a lot of problems, the biggest problem being holes in pistons.

I wouldnt use caltex either, I used it in the kart once, was well down on power, endedup up that the fuel was contaminated and the fuel filter was becoming blocked

[Dan]

Unleaded has a octane level of 95 and super has 97+ thats its like adding octane booster it dont make much different, u every used power pills? they are class

[zaknafien]

do them pill's really work?
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[Kickstart]

[Dan]

yeah they are pritty good u can really notice it

[Dan]

so keth in other words i may as well swhich from super to normal unleaded?

[Kickstart]

[feef]

[Kickstart]

[Dylan]

So is this a definate NO All this science talk, should understand it as ime doing chem a level as well as physics. Oh well, thats what you get from skim reading the posts!!!
Thanks
Dyl