+2, it's not like back in the 70's and 80's, the new ECU's on vehicles takes care of all that, if your not pinging don't change use what's recommended, even Consumers Report says the same thing.Originally Posted by bob109
+2, it's not like back in the 70's and 80's, the new ECU's on vehicles takes care of all that, if your not pinging don't change use what's recommended, even Consumers Report says the same thing.
Have to disagree here. I use mostly 87 and get the standard 40-42. We have a place here that still sells "91 ethanol free", when I use that I get 43-45 mpg. I believe it also runs a little smoother on take offs. During this years rally, when we were in CO, we were getting 50 on some runs, but drop some elevation and get into Kansas, the mpg's dropped into the 30's
Talking about octane, not ethanol vrs pure gas. I agree pure gas what we call here marine gas is better, and much more expensive. Two other things that affect the possibility of pre-ignition are timing advanced motors and high altitude. In other words it is the pure gas causing your better mileage not the octane. I also got better gas mileage while in high altitudes' this summer.
Last edited by 2wheelsforme; 10-24-2018 at 07:30 AM.
As has been stated, using gasoline with more octane than your engine needs is a waste of money. A higher octane rating means the fuel is more resistant to detonation or pinging. In general, engines with higher compression are more prone to detonation. Other factors, like combustion chamber shape, ignition advance, and temperature are also contributing factors. Higher octane keeps the problem under control.
Once you choose a fuel with a high enough octane rating to prevent detonation, absolutely nothing is gained by using a higher octane rating. In fact, higher octane fuels actually have slightly less energy content, so using them unnecessarily could actually decrease performance and mileage by a tiny (probably not measureable) amount.
There's another factor at play. Modern vehicles have engine management computers that adjust for detonation, allowing lower than optimum grade fuels to be used without causing engine damage. Knock sensors tell the computers to adjust ignition timing. So it can be difficult to tell if your engine could use a higher octane fuel.
My personal experience with my 2 old Valkyries and 2 F6Bs has been interesting. My '98 Valkyrie Tourer runs great on any fuel, even the 85 octane junk they sell at high altitudes. In 175,00 miles I've never detected any pinging whatsoever. However, my '99 Interstate pings badly on hot days when accelerating hard with regular fuel. This could be because Honda used an ignition control module with more advance on the Interstates to compensate for the added weight. In the summer I always use mid grade or premium on that bike.
My F6B experiences have been more surprising. I had a 2013 that often needed premium fuel. I had been running 87 octane ('mid grade' at high altitudes) and on a hot day, I heard some brief pinging when accelerating. It quickly disappeared, then returned, then disappeared again, so the computer must have detected it and made timing adjustments to compensate. After that I began using 91 octane whenever the weather was warm. On the other hand, my current 2016 has no problem at all with 87 octane fuel.
I have no idea why the 2013 was so picky. Maybe I had an unusual bike that was slightly out of spec, or maybe Honda upped the power on those early F6Bs. That's happened before, as the '97 Valkyries performed better than subsequent years.
Dave, Thanks for your information. I too have a 98 Tourer with Dyna 3000 ignition set to 7 degrees advanced and the Rev limiter turned off. Although I never run it THAT hard it needs to have Octane to prevent pre ignition problems. It is a very strong runner. I have experimented a little on my 13 F6B as well, just seeing if I notice any difference and I believe I do see some improvements in drive ability performance etc. with Octane boost. I think it just counteracts with all the grain alcohol gas we have here in the midwest. Wish I could find a source that did not have it. Not looking forward to the future , as they are forcing higher % of grain based fuels.
I was thrilled when a Murphy Express station opened near my house recently. It sells mid grade 'pure gas' for a little more than their price for the ethanol stuff.
High octane gas burns slower and cooler. Dip a finger in 87 octane and blow on it. Its gone in a few seconds.
It burns the same way. Fast and furious. It takes less heat to ignite it.
Sometimes just a hot spark plug tip and a little compression will set it off before it time. Spark Knock.
The compression ratio on the B is low enough to burn 87 ok. But it is borderline. Some bikes with a few tenths higher compression may knock on 85-87.
If you have the knock, higher octane will cure it.
I never run less than 89 in anything. They say you can run 85-87 cause the ECU can hear it and adjust the timing.
To me that means there will be knock on the lower octane. We'll just let the computer handle it.
Nothing wrong with that I guess. Its been that way for MILLIONS of miles on Goldwings, and no problems to speak of.
I believe its just easier on the engine to run a better grade of gas.
We all look for the best oil, why not gas.
Its all a matter of opinion. And this is mine.
ITS ALL GOOD
I thought it was understood that higher octane gas is not better gas than lower octane. You should use the one specified for your engine or go up if you suffer from ping or knock.
Well I have not had any issues with the 87 octane, it just so happened that the when I accidentally filled up last time with 92, it "seemed" more responsive.
Placebo??
I think that given Honda's tight specs in engine mapping, what we are seeing is more to do with fuel quality. I do think there are some differences, obviously in the blends, but we all need to consider that there is most likely vast differences between storage at stations. I believe moisture content is probably causing some variance. I usually fill up at HIGH volume stations in my hometown. I have in the past gotten what I think is bad gasoline. In those cases I did notice a difference in the way my vehicles ran. Good discussion! Anyone have any other bad fuel stories?
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