98, 95, Or 91

[All]

The performance advantage with higher octane fuels comes from being able to advance the ignition timing and increase the compression ratio without running into pre-ignition (knocking/pinging/pinking) problems.

Great point. I guess, to notice the advantage, you'd have to actively advance the timing and not just leave it stock.

[TripleZee Dyno]

Re Power
91 95 98 all contain pretty much the same "power" 98 isnt more "powerful" than 91
If it goes better, puts out more power etc with 98 then it means that the state of tune and engine design are designed for 98 rather than 91
Put 98 in an engine designed and tuned to run on 91 and you will lose power.
Put 91 in an engine designed and tuned to run on 98 and you will lose power.
You can equate losing power with losing efficiency, ie less mpg as well.
cheers

[All]

It's funny how many people recommend just recommend 98 across the board. The rationale must be that, because it's more expensive, it's better.

[Owl]

Cheers for the useful and informative information.

[dipshit]

Great point. I guess, to notice the advantage, you'd have to actively advance the timing and not just leave it stock.

Even modifying your airbox to allow more airflow can create a leaner running engine. (efficient modern motorcycle engines are already running rather lean as they are) A lean engine runs hotter and is more likely to suffer from pre-ignition. This combined with crawling through traffic or riding hard on a tight twisty road on a hot summer's day, could run you into engine damaging pre-ignition.

98 will give you a greater safety margin than 91.

[dipshit]

Watch this vid comparing 95 against 98.

[All]

Watch this vid comparing 95 against 98.

Wow, that was very interesting. I wonder if my bike can make use of the higher octane fuel.

[bimotabob]

That's pretty cool to get an extra 30Nm of torque on that fast car from the high octane fuel.
It will be able to sense detonation though, and make changes to the timing as required within it's powerful ECU.

Budget EFI cars never used to have knock sensors and I wonder if bikes do as they although they arent turboed
they are high performance.
Be good to hear a dyno report on a GSXR etc.

I have tried all the fuels on both my 2 stroke and 4 stroke bikes but cannot notice anything at all in milage or HP.

If you run on one type only you can always set your bike up to run best on it ay.

Regards

[dipshit]

Budget EFI cars never used to have knock sensors and I wonder if bikes do as they although they arent turboed they are high performance.

I know my SV hasn't got a knock sensor. What it does (and many other bikes) is to richen up the air/fuel mix under hard acceleration (i.e. load) to safeguard against pre-ignition.

Regardless, I still find it runs better on 98. Seems to pull harder from low revs with less engine noise and more of a deeper tone from the exhausts instead. Also get around 230ks from the 13L before the fuel light comes on instead of around 200ks with 95.

98 is just an overall better quality fuel, well worth another couple of dollars per tank over 95 in my book.

The 91 we get in New Zealand is utter crap.

[All]

I know my SV hasn't got a knock sensor. What it does (and many other bikes) is to richen up the air/fuel mix under hard acceleration (i.e. load) to safeguard against pre-ignition.

Regardless, I still find it runs better on 98. Seems to pull harder from low revs with less engine noise and more of a deeper tone from the exhausts instead. Also get around 230ks from the 13L before the fuel light comes on instead of around 200ks with 95.

98 is just an overall better quality fuel, well worth another couple of dollars per tank over 95 in my book.

The 91 we get in New Zealand is utter crap.

Pretty decent mileage you get there. On my SV, I think I used to get about 120km per tank...

Mind you, that was mainly just town riding.