Lower octane = more power?!

[Corsara]

So, being a relatively new to FZ6 and motorcycling in general, last time I had to fill her up I was in a good mood, so treated her with 91 octane gas. Today it was time to fill up again, and I went with regular 87 octane. Immediately after that I felt like it had more power (read harder acceleration).

Is this just in my head or there is truth? Not to mention that I went from almost empty (had 30km on reserve) to full tank, which added more weight, and still---it felt like it was pulling more!

 

[Corsara]

Oh crap, sorry, just noticed there's a whole thread with a poll about that...still, if you have a direct opinion on my question, won't hurt to share it

 

[chomorro]

So, being a relatively new to FZ6 and motorcycling in general, last time I had to fill her up I was in a good mood, so treated her with 91 octane gas. Today it was time to fill up again, and I went with regular 87 octane. Immediately after that I felt like it had more power (read harder acceleration).

Is this just in my head or there is truth? Not to mention that I went from almost empty (had 30km on reserve) to full tank, which added more weight, and still---it felt like it was pulling more!

Maybe Lower octane burns faster so gives more power combined with our compression rates?? :eyebrow:

I dont know but i have always ran 91 so now im going to try 87 and see what happens :Flash:

 

[ChevyFazer]

Sorry but its just in your head...besides it tanks more then 1 tank to actually feel the effects

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[DDS]

It's like when you car feels fast after you've just washed it. All in your head nothing to be ashamed of though. To be honest it feels quicker when I fill up. But only because I've been babying the hell out if it because it's running reserve lol

 

[Jacobien]

Octane determines the ignition point. Lower octane fuel will ignite earlier (can't recall why, but its true). What creates power is when the fuel ignites at exactly the right point within the combustion cycle.

Higher octane therefore reduces premature ignition, resulting in a more optimal combustion cycle. That's why you get 91 at high altitudes and 97 at sea level - different atmospheric pressure = different ignition point.

An engine is also more prone to "pinging" with low octane, which is premature ignition.

Long story short, it is in your head. Must have been down to other external factors, air temp, humidity etc.

 

[ChevyFazer]

Octane determines the ignition point. Lower octane fuel will ignite earlier (can't recall why, but its true). What creates power is when the fuel ignites at exactly the right point within the combustion cycle.

Higher octane therefore reduces premature ignition, resulting in a more optimal combustion cycle. That's why you get 91 at high altitudes and 97 at sea level - different atmospheric pressure = different ignition point.

An engine is also more prone to "pinging" with low octane, which is premature ignition.

Long story short, it is in your head. Must have been down to other external factors, air temp, humidity etc.

I wish I could buy some octane 97 around here!!!! Althouh I do have a little octane 113 in a 55 gallon drum left over from the race truck ...although that might be a bit much

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[FinalImpact]

If the EZ actually monitored the engine condition in detail, it could likely run a more aggressive ignition advance curve and make more power on higher octane fuel. But it doesn't. So there is little benefit in running higher octane fuel.

However; I've found that as it gets warmer out, my 08 pings from a take off on occasion on 87 octane.

My 2 cents: If its in the lower 60's (F) to upper 80's run regular. If its in the 90's to 100's I'd fuel it with higher octane 92+ so as to reduce detonation at low RPM take off.

As for the OP's statement, the FZ fuel mapping is designed for 87 octane and in this case, the air temp, barometric pressure, and humidity between the two fuel ups played a bigger role. On cold wet days the air is denser and when it fills the cylinder it expands more giving more cylinder filling volume per burn than does hot dry air. Hence the reason why turbo charged vehicles often use air to air inter-coolers to cool the intake air back down after being compressed but before being sent to the engine. Remember, if you compress air it gets hotter and expands.

 

[kdburtch]

air temp has a significant impact on H/P, but also using the right grade fuel for compression ratio helps, with the FZ thats regular unleaded. As for Higher octane being better, unless you have high comp pistons your wasting your money. The high octane cost more due to a greater difficulty in refining, not being a superior fuel.
For all those high octane people out there i have some property I would like to sell you with a fountain of youth on it.

 

[gusss]

older models...fz6s they have injection map for 87 octane
newer models .. fz6s2 they have 91 octane maps...

check manuals!

I have 87 octane bike and have used up to 100 octane to compare...
As we speak, using only 87 octane. that is the best the bike will run.

My next project is to advance timing just a little probably 5 degrees, now then I would ONLY be using premium!!!

 

[ChevyFazer]

air temp has a significant impact on H/P, but also using the right grade fuel for compression ratio helps, with the FZ thats regular unleaded. As for Higher octane being better, unless you have high comp pistons your wasting your money. The high octane cost more due to a greater difficulty in refining, not being a superior fuel.
For all those high octane people out there i have some property I would like to sell you with a fountain of youth on it.

So I guess all of those dyno comparos were photoshoped

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[DigitalOverride]

In Norway, the Owners Manual (which also applies to other Scandinavian/Nordic countries) lists the recommended fuel type as 95 octane, which makes sense because we only have a choice between 95 and 98.

Like others have said, I would think that octane levels would be dependant on other factors, and without sufficiently advanced electronics capable of adjusting ignition point and combustion cycles, higher octane likely will literally just burn more cash.

 

[ChevyFazer]

As for 87-95 honestly if you can feel a difference then your probably hyper sensative but I have run actuall racing fuel octane 113 in almost everything ive owned except the bike (Nervous about burning something up) and when you step up to a real fuel it dont matter about anything else you will feel a difference

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[FIZZER6]

air temp has a significant impact on H/P, but also using the right grade fuel for compression ratio helps, with the FZ thats regular unleaded. As for Higher octane being better, unless you have high comp pistons your wasting your money. The high octane cost more due to a greater difficulty in refining, not being a superior fuel.
For all those high octane people out there i have some property I would like to sell you with a fountain of youth on it.

Higher octane fuel these days is more than just an octane rating. The premium fuels (especially Shell/BP) have a superior additive (detergents) package that keeps the fuel injection system and valves much cleaner than the regular fuel additives will. Over the lifespan of an engine using premium is going to result in a significantly cleaner, better performing motor. The extra cost of premium over regular is only about 7%....in the grand scheme of things that is not much...especially since many users experience a smoother running motor with less vibrations which means less engine wear.

 

[Abschatten]

I actually just went from 87 octane to 93 and found that my bike seems a little louder but i think it is just my head playing games with me. The bike does seem more powerful but as i said before i think its my head.