Bonneville America Forums Forums Technical Forums General Tech Octane again

Last couple of rides it seems that my America has been running a little sluggish for some reason or another. I decided to try some 93 octane mixed in with the 89 that was allready in the bike half full. Seemed to run much better. Hope that it wasn't my imagination. Next fill up I think i'm going to switch to 91 octane for a while.
Anyone ever notice the same thing with their bike?

jerry, just my 2 cents, but if it started running better when you tanked up, sounds like maybe some dirt settling in the tank or more likely water, and it likely wouldn't have mattered which octane you used. I've been running 89 since day 1 and have 23,000 miles with no complaints. Save your money.

Higher octane fuel lights off and burns slower. A continuous diet of higher octain than needed can lead to exessive deposites in the engine and, possibly, burnt valves.

My Owner's manual says to use 95 RON, what is that in US octane ratings?

I've always run with Chevron's mid grade gas. The only time I've been dissatisfied is during the winter months when they add the oxygenating garbage. My gas mileage goes to pot then. I also avoid Ethanol. It doesn't perform as well in the mileage department either.

Welcome to the board, Scott!

Here's a great explanation of the octane rating(s):

http://en.wikipedia.org/wiki/Octane_rating

And Scott, a quick answer to your question is: in the USA, that RON 95 is about 91.

Many months ago, through another bike web site, I found a link to an article about gasoline, written by an engineer who worked at a major oil company.

Into his older, pet Corvette, he put 3 different major brands of gasoline on a rotating basis. The reason for this is that some (and only some) oil companies put in, the new, car manufacturer-recommended, special detergent. (As I recall, he switched at around 5000 mile intervals, as that was easy for him to remember.)

Each oil company's formula for the cleaning agent is different, and each one does its own special job of cleaning. To get the optimum benefit, this guy switched around.

Chevron has it; Exxon-Mobil does too; and so does GT.

Some of the big oil companies only put it in their highest octane brew - 91 or 93 (RON+MON/2), but GT puts it in all their octanes. [OK, we all know that there are only 2 octane gasolines brewed, and the middle octane is a 50-50 mix of the low and high gas.]

I have noticed that different areas around the country have different standard octane levels. Here in Oregon, regular is 87, premium is 92. In Utah regular is 85 and I found premium to be either 89 or 91 depending on the gas station.

Soren

EXXON-Mobil Mid-grade. No problems at all.

Mid grade whatever, whenever the America needs some. There is a Chevron near home that I use frequently, but I won't push the BA past any gas pump to get to a certain brand. I don't notice any difference in mileage or performance between brands. I do however, try to buy gas from places that seem to sell a lot of gas, hoping not to get either gas that is old or made for a different season. If you don't get knock or ping, the lowest recommended octane is best. IMHO Triumph recommends mid grade just as a little insurance that knock or excessive ping won't occur. In stock (no compression increasing mods) condition, my BA doesn't knock or ping on mid grade, so I'll stick with that until I hear differently from my motor, Triumph or knowledgable forum members.
Does anyone know why our bikes aren't very effecient converting gas to power?? As mentioned on a different thread recently, some small cars get as good or better mileage as BAs/Speedys.

Longmtnman,
I'd put my money on fuel injection and engine managment computers. With newer engines that use direct injection, closed loop controls like O2 Sensors, Knock Sensors, Air Mass Sensors, etc..., and a computer to control it all, you can squeeze a lot more efficiency out of a lot leaner mix. I'm quite sure that plugging all of that onto our engines would eak out even more power and fuel economy. Of course, our engines would be more expensive and complex as well. Might happen eventually...

PapaDean- Thanks! I read that same wikipedia page before posting, was hoping to find a conversion chart from RON to AKI or R+M/2.

I put 93 in the other day, maybe I'll scale it back to 89 next time.

Thanks Bayern710, I see you're from (I think) the home of the giant peach. We used to go I-85 to Atlanta on our way to Talladega each year.

Oops, thats Greer, SC, not Anderson. I had a momentary lapse of reason.