100 Octane

[k14]

Went TOO well outside Dangerous Drop-in Dwelling but that's another story...

Yeah theres quite alot of hooliganism that goes on outside that house. Heard that there was some sustained loss of traction the other day too. Pity you weren't there or you could have given em a ticket

[sAsLEX]

It's pretty hard to increase mechanical compression on the fly,

it has been done, the whole top half of the motor would rotate to shorten the combustion chamber to increase compression and then the the other way to lengthen when used with a turbo, was rather ingenious


linky:http://www.popularmechanics.com/auto...y/1266656.html

[Acid]

i heard 96 from gull is imported from overseas

[Toast]

i heard 96 from gull is imported from overseas

Yep, pretty sure it is. I reckon my bikes like that stuff even more than the BP 98 too.

[quickbuck]

You could use 108 octane (AvGas)

Since when????

There is 100 octane avgas (Green)
100 octane low lead avgas (Blue)
115 Performance rating avegas (Can't remember the colour as it was 15 years ago when I did my mechanics course)
140 Performance rating avgas (purple)

Most avgas used in NZ is the good old green river.

Note: You can't get an octane rating above 100, that is why it is called "performance rating".

To put an extra 2 cents in, my CBR goes best on 98 (or 8000 if I stop at Mobil).
It isn't wise to just fill your bike with avgas either, as the amount of lead in it is enormas, and the deposits will fowl your little plugs in no time. The aircraft I use to maintain used to get their plugs serviced every 30 hours (yes, not long), and they were well caked in that time.

[KLOWN]

octane booster is not good for your bike/car I had to run minimum 98 on my skyline and was running octane booster on top of the 98. When I had it dyno'd the guy told me to not use occtane booster it damages the spark plug and contaminates(sp) the fuel system with shit. If you want higher octane fuel you can buy it from pioneer(sp) I ran a fuel called ms103 its 103 octane and is $5 a litre or cr12/cs12 (can't remember the name) which has even higher octane and is $20 a litre. Av gas is no good for cars or bikes because it is designed to run at 2000-3000rpm or 3000-4000rpm, I can't remember.

[KLOWN]

i heard 96 from gull is imported from overseas

isn't all our petrol imported?

[Bonez]

Since when????

Hey isn't AVTUR the best? The AV means it flys and TUR stands for TURBO after all doesn't it?

[quickbuck]

Hey isn't AVTUR the best? The AV means it flys and TUR stands for TURBO after all doesn't it?

Yeah, that's it bonez

[Hitcher]

isn't all our petrol imported?

No. Thanks to the "gold-plated" refinery at Marsden Point.

[scumdog]

Yeah theres quite alot of hooliganism that goes on outside that house. Heard that there was some sustained loss of traction the other day too. Pity you weren't there or you could have given em a ticket

Yeah, just lucky for them I wasn't there eh?

Where's a policeman when you need one???

[bobsmith]

ok, just my 2 cents worth.

Octane rating is NOT a measure of how much "octane" is in the fuel.

Rather it is what is called an "anti knock rating" It is a measure of how resistant the fuel is to a "knock" which refers to explosive combusion of fuel inside the cylinder. (you want the fuel to burn nice, evenly and gradually) By having a higher octane rating you are able to run your engine at higher rpm and temperatures without getting "knocks"

So seeing that fuel with rating of 91 is more volatile than 98. If your engine is properly tuned to 91, it will run much better and efficiently. You can use fuel of higher rating without doing damage but you should avoid using fuel of less octane rating that the one the engine is tuned for.

Octane rating is based on what the engineers back in the days when additives were not available and fuel quality wasn't as high decided the maximum anti-knock properties would be for fuel and is based on that. So theoritically a fuel with octane rating of 100 would have the best anti knock properties possible.

Since fuel tech has advanced, now you are able to get fuel with octane rating of greater than 100. For example, avgas used in New Zealand has octane rating of 110 which means its anti-knock properties are 10% greater than what they thought a while ago was the maximum obtainable. In some other parts of the world they use octane rating of 120 for avgas.

I can't remember what the hell I'm supposed to be talking about but hope this helps.

(edit) - anyway the point I was trying to make is that higher octane rating does not equal more power without retuning the engine for the fuel. and if you use lower octane rating you increase the chance of knocks which can damage your engine. And so in hotter temperatures use higher octane rating.

[boomer]

But at least it would make a noise??

oooooooohhhh :eyepoke:

i'll store that one for later

[Fooman]

Octane rating is based on what the engineers back in the days when additives were not available and fuel quality wasn't as high decided the maximum anti-knock properties would be for fuel and is based on that. So theoritically a fuel with octane rating of 100 would have the best anti knock properties possible.

Actually the octane rating was set by a direct comparison between 2 hydrocarbons. Heptane, (C7H16) and 2,2,4-Trimethylpentane, also known as ...(drum roll please)...iso-octane! 2,2,4-Trimethylpentane is an isomer of octane - both have the same chemical formula, C8H18, (well technically iso-octane is (CH3)3CCH2CH(CH3)2 ) but different structure.

Heptane was set at an octane rating of 0, iso-octane was set at an octane rating of 100, and any fuel was compared to those and mixtures thereof, to assign an octane rating. Fuels with higher octane ratings (e.g. ethanol at 108ish) have been around since the octane rating was developed, 100 wasn't set as the maximum that could be reached at the time.

Hopefully, the following will all line up (plese be a fixed width font!) (dots are for alignment only - forum doesn't like leading or double spaces)

Heptane =

..H H H H H H H
..| | | | | | |
H-C-C-C-C-C-C-C-H
..| | | | | | |
..H H H H H H H

Octane=


..H H H H H H H H
..| | | | | | | |
H-C-C-C-C-C-C-C-C-H
..| | | | | | | |
..H H H H H H H H

iso-Octane =

......H........H
......|........|
..H H-C-H..H H-C-H H
..|...|....|...|...|
H-C - C -- C-- C - C-H
..|...|....|...|...|
..H H-C-H..H...H...H
......|
......H

Cheers,
FM

[guzziguy]

I don't trust 95 octane any more. Used it a couple of times and bike performed like it was running out of gas all the time. Switched back to 91 and threw in some injector cleaner and she's sweet again. Oil companies put 'slops' back into 96 octane (I worked for one for 20 years)- it's a mix of everything they store resulting from ship discharges. They can't put it into 91 coz it's easy to put it out of spec. It is monitored/tested and should be fine but you never know do you? As for 98, if they had it in Nelson I'd run the bike on it all the time. The spec is very high, performance is better, it's cleaner and more economical (probably because you reach cruising speed with less effort).