shell optimax more k's?

[martin]

I've just come back from Oz....short holiday and my mate uses optimax in his car and he gets 150 more k's than normal fuel, does anyone know if it works for bikes too?????????

[kickingzebra]

Believe it when I see it, but I don't think it is available here anyways, could be wrong though.

[SLight]

Cars have a lot bigger tanks than bikes do. But higher octane gas give a better combustion. There fore you should need as much of the old right hand to get the bitch going a bit harder easier. I some times run a mix of AV gas and 96 in me bikes. Works good. Also higher octane can make the engine run a little cooler due to a faster more efficent burn.

[paturoa]

How long was his nose?

Its all bs, the octane rating roughly translates to what compression / temp you can take it to b4 it spontaneously combusts for a given configuration. ie high octane for for high compression. Some motors can run lower octane gas at higher compression, down to design and a whole bunch of toher factors.

For petrol the optimum mixture is about the same across the normal octane ratings for pump petrol. For higher compression engines the mixture ratio doesn;t change much, you just get to burn more for each bang.

The "energy" released by the same mass of petrol across the avail fuels is as near as dam the same.

So putting high octane fuel into a motor that is setup for say 91 really wont make any difference. The carb / FI will pump in the same amout of fuel and as the compression ratio is fixed and the mixture is fixed and the energy is about the same ... its all BS

[SLight]

Shell have that optima 98.

[kickingzebra]

I had a 300 zx and was much hyped up about 98 when bp started getting it a few years ago. translated to no real difference unless I was giving the damn thing absolute death.
I always put higher octanes in the bike, but probably more for image, cause again, I notice no real difference unless riding really hard.

[kiwifruit]

150km is a massive diffeence
u sure he wasn't pulling your leg?

[martin]

no he always uses it . but like you say its a much bigger tank

[Meanie]

I've just come back from Oz....short holiday and my mate uses optimax in his car and he gets 150 more k's than normal fuel, does anyone know if it works for bikes too?????????

You believed an Australian
Good on ya mate

[nadroj]

Cars have a lot bigger tanks than bikes do. But higher octane gas give a better combustion. There fore you should need as much of the old right hand to get the bitch going a bit harder easier. I some times run a mix of AV gas and 96 in me bikes. Works good. Also higher octane can make the engine run a little cooler due to a faster more efficent burn.

Higher octane = slower burn - Fact

Higher octane = bigger bang when used in higher compression.

The only thing higher octane does is allow more timing advance or higher compression without detonation - hence your engine needs to be set up for it to have any effect.

[Fatjim]

Sorry Nads but I've heard this octane bullshit before, and even spouted it myself.

I get better economy on 95 than 91. It may not be the octane, may be better quality fuel. But I definately and provably (is that a real word) get 10% more millage out of 95. So it's cheaper to use.

I did hear a rumor that 91 in NZ is worse than tap water and the 98 is made in Oz.


Also the guys on the OZ VTR mailing list I'm on hate the Optimax stuff. Got something to do with the additives affecting internals

[Bonez]

The only thing higher octane does is allow more timing advance or higher compression without detonation - hence your engine needs to be set up for it to have any effect.

That reminds me. I haven't gotten around to retarding the GSX timing yet. It hates 91 when under load.

[paturoa]

Sorry Fatjim but the reason you may get better milage with 95 is cos of the tuning of your bike.

As a general rule vehicles wont run differently with higher octanes. In other words an engine that is designed and tuned (optimised) for say 91 wont have any significant difference running a higher octane fuel.

Sounds like your bike is better tuned to 95 and runs worse on 91. If you tune for 91 you'll get the same performance as you do on 95 at ?? cents per litre less. Suggest you check your advance.

Check out section 4.9 in the following.

http://www.faqs.org/faqs/autos/gasoline-faq/part1/