[Greengoose]

I know this has been addressed before and I think the answer was that using high octane didn't do anything for performance.

However. Yesterday I filled up at the Indian reservation which only has 87 and 91 octane. The 87 was out of order so I filled up with the 91. I didn't give it much thought past that. Today as I came back into vegas and started driving in heavier traffic. I noticed that when I cranked on the throttle, it responded better than normal. I did this about a dozen times or so and I was quite positive that it WAS responding better. Then I remembered that I filled up with the high octane.

Is this my imagination or is it acting better? Has anyone else experienced this?
-Bryan

 

[Brian]

AFAIK, a higher octane rating in and of itself shouldn't result in higher performance in an engine that runs well on lower octane.

However it's possible that the lower octane fuel is also mixed with ethenol as a cost cutting method, and ethenol -- although it reduces pollution when added to gasoline -- has a lower specific energy than gas.

Of course, I'm not an automotive engineer, and maybe my information is incorrect. Some have reported better acceleration with Premium, others have reported rough idling and misfiring at moderate speeds with it.

Try different brands and different grades, and buy what works best with your particular bike and riding style, I guess.

 

[dabimf]

The manual states to use fuel with "at least" 87 octane. The compression ration on the Burgman 650 is 11.2 to one. That's pretty high for the use of 87 octane. However, the engine design has a lot to do with whether or not 87 octane fuel will knock or not in an engine with that compression ratio. Basically the purpose of higher octane gas is to prevent engine knocking caused by predetination of the fuel.
That being said, I know that in cars where premium gas is required, one can use 87 octane fuel in the same vehicle. These vehicles are equipped with engine knock sensors. These sensors detect engine knock that you can not hear. When the engine knock is detected the sensors cause the ignition timing to retard slightly to prevent the engine knock. This in turn will lower engine performance slightly. The vehicle will run but not at peak performance.
I don't know if the Burgman is equipped with these anti knock sensors or not. Maybe someone can chime in here who knows more about these bikes than I do. If these bikes are not equipped with these sensors then I believe the engines are designed to run on 87 octane since they do not knock or at least I can't here the engine knocking if it is.
I personally use 89 octane fuel for two reasons. The first reason is that it has been shown that when you pump 87 octane fuel, it can be 87 octane or slightly less depending on how old the fuel is and the qualilty of the brand. I figure, and without any scientific basis, that if I use 89 octane and it is off an octane number or so I am still using the minimum octane level required. I have tested all octane levels of fuel and I get the best mileage from 89 octane.
Hope this helps a bit.

 

[Brian]

87 octane fuel at my local Arco station went from $2.30 a couple of weeks ago to $1.99 as of last night, and I assume other grades dropped in price as well (since I've always bought 87 I haven't really paid attention to the others).

Maybe I'll try a few tanks of 89 and a few of 92 and see what my results are. I'll post them here when I've tabulated my cost per mile figures.

 

[dancote]

Re: High octane...better performance? No

I know this has been addressed before and I think the answer was that using high octane didn't do anything for performance.

Is this my imagination or is it acting better? Has anyone else experienced this?
-Bryan

The short answer is higher octane does not improve performance. See http://www.ftc.gov/bcp/conline/pubs/autos/octane.htm

Regards,

Dan

 

[pauljo]

In Nebraska, 89 octane is cheaper than 87 octane. That is because it has a fairly high percentage of grain alcohol in it, and there is a law here that they can't charge as much for grain alcohol as they do for gasoline. But I won't run it in any of my vehicles - based on articles I've read in the past that argued that the alcohol is not really good to put in a vehicle. I think it had something to do with causing fuel lines and gaskets to deteriorate over time - I don't remember exactly. Anyway, back when I read those articles, I made a mental note to avoid that stuff.

So my choices here are 87 octane and 92 octane. Since all my vehicles run well on 87 octane, including my two high compression Suzukis - I can't see paying for 92 octane. I believe that any performance gain would be very slight, and from some folk's reports, fuel mileage might even drop a bit. I did try a couple of tanks of high octane in my V-Strom last year and it actually ran worse on the high octane. The V-Strom engine has slightly higher compression than the Burgman 650.

If 92 octane made an "Oh My God" difference in performance - you know I'd run it. But the rider reports I've seen don't indicate that. A barely perceptible gain in performance is not worth the additional cost in my opinion.

 

[Randy]

Some test I did showed I did not get better mileage with high test but I also felt like the bike did respond better but after reviewing these posts I guess it was just my imagination.
It just seems funny that at 70 mph riding in a head wind 87 octane will give the same performance as 91 .
Just don't seem to remember it working that way back in my hot rod days.:lol:

 

[pauljo]

Just don't seem to remember it working that way back in my hot rod days.:lol:

Nope - it sure didn't. One of my friends had a '51 ford coupe. Offenhauser 11:1 high compression heads on a '53 Merc flathead V-8. Hot cam, 3 deuces, Mallory dual point ignition, etc. The only gas that thing would run on was Sunoco 260 (highest pump octane available). It would still ping occassionally.

I know. The younger guys are saying "flathead?", "3 deuces?" :dontknow:

Had to be there...

 

[Brian]

Re: High octane...better performance? No

...See http://www.ftc.gov/bcp/conline/pubs/autos/octane.htm

Thanks for the link. It's good to know what the "official" position is.

For more on the unofficial position see the discussion in the Burgman 650 forum under "gas mileage."

http://burgmanusa.com/forums/viewtopic.php?t=1411&start=15

 

[Brian]

...But I won't run it in any of my vehicles - based on articles I've read in the past that argued that the alcohol is not really good to put in a vehicle. I think it had something to do with causing fuel lines and gaskets to deteriorate over time - I don't remember exactly. Anyway, back when I read those articles, I made a mental note to avoid that stuff. ...

I double checked my Owner's Manual, and Suzuki says you can run gasohol with up to 10% ethenol (grain alcohol) or 5% methanol (wood alcohol). Or MTBE up to 15%. (It's either/or -- MTBE is not used as an oxygenator when alcohol is used.)

They add a strong warning about methanol: "DO NOT USE fuels containing more than 5% methanol under any circumstances. Fuel system damage or motorcycle performance problems resulting from the use of such fuels are not the responsibility of Suzuki and may not be covered under the New Vehicle Limited Warranty or the Emission Control System Warranty."

Based on that warning, I'd avoid any methanol just to be safe.

Here in Washington, gas pumps are required to have a label indicating what oxygenating additives are used and to what percentage, but not all states do so. If you don't see it, ask...but be prepared for shrugs and "I dunno" from most attendants.

 

[Brian]

...One of my friends had a '51 ford coupe. Offenhauser 11:1 high compression heads on a '53 Merc flathead V-8. Hot cam, 3 deuces, Mallory dual point ignition, etc. The only gas that thing would run on was Sunoco 260 (highest pump octane available). It would still ping occassionally. ...

"Back in the day" I had a 1969 Pontiac GTO that was pretty well tricked out. Unless I kept my foot out of it, it would ping mercilessly on any regularly obtained gasoline grade. Since I had a lead foot that might have presented a problem, but I had a ready supply of 100 octane avgas (aviation gasoline) available -- for a price. It worked "really sweet" as the kids would say. Unfortunately I only had it for a little over a year when I got forced off the road in the snow by a nut-case in a Jeep. I ran square on into a big oak tree. Turned the "outy" on the grill into an "iny" of major proportions. I really miss the old goat.

 

[Randy]

I used that stuff also (burned out a few valves with it) and the price was not bad.

but I had a ready supply of 100 octane avgas (aviation gasoline) available -- for a price.

Of course when I started driving regular gas was a around twenty five cents a gallon. 8)

 

[pauljo]

Of course when I started driving regular gas was a around twenty five cents a gallon. 8)

Model A? Just kidding. Actually I have driven a 1931 Model A. I remember regular gas at about 35 cents a gallon. Of course there were frequent "gas wars" too, which could drive the price down a bit.

And don't forget, at 35 cents a gallon it was full service and you got your windshield cleaned and oil checked in the process!

 

[Brian]

And don't forget, at 35 cents a gallon it was full service and you got your windshield cleaned and oil checked in the process!

I remember 23 cent/gallon gas. I also remember earning 85 cents an hour at my after-school job as a pin chaser at a bowling alley.

If that ratio still held up, gas would be $3.75 per gallon, so it's actually cheaper for me now in relative dollars.

Doing that comparison was a real eye opener. :shock:

 

[Chumly]

[quote="dabimf"That being said, I know that in cars where premium gas is required, one can use 87 octane fuel in the same vehicle. These vehicles are equipped with engine knock sensors. These sensors detect engine knock that you can not hear. When the engine knock is detected the sensors cause the ignition timing to retard slightly to prevent the engine knock. This in turn will lower engine performance slightly. The vehicle will run but not at peak performance.Hope this helps a bit.[/quote]

The knock sensors will not always stop knocking. On a hot day my 2002 Miata will still knock under heavy loads with 87 octane.

 

[pauljo]

Well, after my just completed trip to the Black Hills of South Dakota, I'm whistling a different tune... Yep, the 650 will run without complaint on 87 octane as I've been saying. But she appears to be a bit of an alcoholic. I started running the mid-grade gas with 10% ethanol (corn based alcohol) on the trip. She definitely accellerates stronger in the upper speed ranges. Not my imagination. On this trip I was cruising at 85 mph indicated on I-90 and getting only 40 mpg. I decided to try the alcohol laced mid-grade gas. Same mileage. But hold on to your hat when you twist the throttle to pass a truck at 85 mph!. She screamed past the truck and was still accellerating strongly at 104 mph, when I cut the throttle back. And that was fully loaded for touring... So, same mileage, big gain in high speed passing power, and five to eight cents cheaper than 87 octane - I decided to run the mid-grade for the rest of the trip.

Hi, my name is Burgman... And I'm an alcoholic...

I really don't know whether to put her back on the 87 octane, or just keep feeding her the cheaper happy stuff....

 

[Monterey10]

Gasoline

High octane gas burns a lot cooler than regular.

Regarding mileage, I've had big improvements in fuel economy/power
using 49 state gas. The California gas has a lot of oxygenators
that don't burn so well. I used to get 44 mpg on my Kawasaki with Ca gas, I got 56 mpg on Oregon gas.

I've noticed that Shell has a fuel that uses gives better mileage. I've
heard that it includes friction reducers, thus the better mileage.

 

[pauljo]

Some octane trivia from the S.D. trip.

At home, and at most gas stops on the trip:
Regular unleaded = 87 octane, Mid grade = 89 octane

At Rapid City, South Dakota (just outside the Black Hills):
Regular Unleaded = 85 octane, Mid grade = 88 octane

At West Point, Nebraska (last fill up of trip)
Regular unleaded = 88 octane, Mid grade = 90 octane

(All Mid grade gas was enhanced with 10% ethanol.)

 

[lifegetter]

Some octane trivia from the S.D. trip.

At home, and at most gas stops on the trip:
Regular unleaded = 87 octane, Mid grade = 89 octane

At Rapid City, South Dakota (just outside the Black Hills):
Regular Unleaded = 85 octane, Mid grade = 88 octane

At West Point, Nebraska (last fill up of trip)
Regular unleaded = 88 octane, Mid grade = 90 octane

(All Mid grade gas was enhanced with 10% ethanol.)

http://www.faqs.org/qa/qa-19161.html points out the reason for lower octane requirements in Colorado.