What octane fuel you using?

[cbdtran_imp]

So, yesterday, I rode 450 miles (along the Ilinois River Rd. from Chicago to south of Peoria. Nice ride, but I digress). I've been an "87 is fine" guy for this bike since I purchased it 5000 miles ago. On a whim, I started using 93 on this trip. I figure I had about half the trip with 93 and half with some blend of 87 and 93. There are far too many variables to list, so it is impossible to tell for sure that octane had anything to do with my impressions, but I did feel that acceleration, particularly when starting in 2nd gear, improved. I did not check fuel consumption. I am not suggesting that anyone buy higher octane to improve performance, but I am going to toy around with 93 and 89 octane for awhile and see if what I think I felt was something other than my imagination.

I used 87 after few thousands on 91, when i switch back to 91, I perceived it got more power and the engine response was better. since then I used 91.

The bike can run on 87, but more octane, more power. it is the laws of physics. All expensive sport cars recommend 91

[flynrider]

So, yesterday, I rode 450 miles (along the Ilinois River Rd. from Chicago to south of Peoria. Nice ride, but I digress). I've been an "87 is fine" guy for this bike since I purchased it 5000 miles ago. On a whim, I started using 93 on this trip. I figure I had about half the trip with 93 and half with some blend of 87 and 93. There are far too many variables to list, so it is impossible to tell for sure that octane had anything to do with my impressions, but I did feel that acceleration, particularly when starting in 2nd gear, improved. I did not check fuel consumption. I am not suggesting that anyone buy higher octane to improve performance, but I am going to toy around with 93 and 89 octane for awhile and see if what I think I felt was something other than my imagination.

I used 87 after few thousands on 91, when i switch back to 91, I perceived it got more power and the engine response was better. since then I used 91.

The bike can run on 87, but more octane, more power. it is the laws of physics. All expensive sport cars recommend 91

The notion that octane = power probably comes from the same "physics" dictionary that says turbo = faster.

Octane is an anti-knock index. If your engine isn't detonating with 87, it isn't going to run any better with a higher anti-knock number. Expensive sports cars use 91 because their high compression engines will detonate with lower octane.

Some more sophisticated car engines will retard the timing if it's knock sensors detect detonation (which means you probably fueled up with a lower than recommended octane). It that case, it will produce more power with a higher octane. As far as I can tell, there are no knock-sensors built into the CB11 engine and the compression ratios are not high enough to warrant using higher octane to prevent detonation.

[Hittheroad_imp]

I only use 91 octane because it's the only gas I can get without ethanol in it. I would run 87 if I could get it without ethanol.

[Jim21680_imp]

Hmmm....this gets the gears in my head churning a bit.

If more octane = more horsepower....
Do you think filling up with diesel would boost the torque up a bit? 2nd gear wheelies could be fun

[Deanohh_imp]

91 does not produce more energy than an equal amount of 87..... Unless the 87 has ethanol and the 91 does not.

as for presence of knock sensor, refer to post #23.

[rboe]

I gave up on cheap gas about four cars ago. Top Tier gas is cheaper in the long run for me and I agree it's a better choice than choosing a higher octane fuel (assuming it's not required).

[rboe]

A small point here; higher pressure can be achieved by shoving in more air and fuel (super charger/turbo charger) or having the pistol compress the volume more. In any event you are getting a higher compression ratio since the math does not really care how you do it. The higher octane rating means the fuel is harder to ignite and when you compress a volume of fuel and air you create a lot of heat which can cause fuel to burn long before you want it to. The fuel its' self does not contain more energy. For that you would have to move to diesel.

So I follow your logic on why you want to say octane is power it is inaccurate as higher octane means less destruction of the motor since you won't get pre-ignition or pinging. Following that logic I could say water=power and they will use water injection on some super/turbo charged engines so they can create more power without blowing up. turbo=faster could more accurately be stated as turbo=quicker, in any event I think you are on thicker ice with that statement.

[AzBob_imp]

Right, but I'm pretty sure he's referring to the colloquial understanding of the concepts by your average person who thinks that simply adding high octane fuel to a vehicle spec'd for low-octane fuel will make it faster, or that simply because a vehicle has a turbocharger on it, it's faster than any car without one.

Both of those concepts would be wrong.

[rboe]

Well the Germans were fond of using diesel in their armor. Then there are railroad power units (where torque is King, diesel electrics).

But not even Harley makes a diesel electric. Now THAT would be a Bike!

[Tripod_imp]

I, for one, am glad for this thread. I am learning a lot!