Bonneville America Forums Forums Technical Forums General Tech (Topic) Fuel Octain

I use only premium high octain fuel in my bike.
So what do ya'll think? Am I waisting my money on the premo-fuel, yes or no?

Same here.. premium always.

Touchy subject for some. Seems there are those that believe there is evil juju in the reg. octane and won't even stand by a pump with 87 in the hose. So, I don't want to offend anyone or be accused of witchcraft, but here's what I know.
1. The higher the octane, the more spark retardant - i.e., the more reluctant to pre-detonation. That's why you use high octane in high compression engines - so the fuel ignites at the proper point in compression - That's ALL. It ain't cleaner. It don't smell pretty. It won't change your fuel mileage - UNLESS you NEED it to run more efficiently, i.e., you're pinging. And it don't even taste any better.

The things that come to mind that MAY effect the need where high octane may be needed where it NORMALLY shouldn't are; Rockies type high altitude and poorly timed engine.


2. I have used ALL available fuel octane ratings, under varying climate and available altitudes and have found NO difference in performance, consumption, or pinging.

3. As a rule, I USE mid-range (89) octane, simply because the book says to.

4. What you SHOULD use, is fresh fuel, supplied by reputable manufacturers, of an octane rating that does NOT allow pinging (pre-detonation) under your conditions.

Now I am going to go and hide and let the 'High Octane Inquisitors' have their say and build their bonfires.

If someone tells you that you are wasting your money, are you going to change to a different octane, or are you just going to keep putting what is marketed as premium in your bike? With 542 post Chy has been around long enought to know what answers you are going to get, and he has not changed his fuel use. Vegas

mid grade and never a problem

Frank

I too have tried all three. I bought reg. when that was all that was available after one of our hurricanes and it did ok. I always buy 89 mid which is recommended. I would never buy less than recommended unless I had too. I noticed no difference with premium over mid after trying 2 tank fulls and decided why spend the money. FYI - I ride primarily near sea level.

89 octane Sunoco, unless I'm out and about and in dire need.
Then it's 89 octane whatever.

Our family 650 Bonny (1970) won't tollerate the low octane now sold as "gas". 91 is as high as we can find here in the Phoenix area (except for av gas) and it pings like mad, even with the timing retarded.

Of course, retarding timing slows down the bike. Ugh.

(And yes, we used octane booster for awhile.)

Well, I was wondering when this subject would come up again. We've added a few members since last time .
pipedr pretty well summed it up, but let me add what octane is and is not.
Is:
A rating of the fuels resistance to ignition. That's it.

Is not:
A measure of the quality of the fuel.
A measure of the amount of power available from the fuel.

In fact, using a fuel with too high an octane rating for your engine can cause you to lose power and fuel mileage as the fuel may not burn completely.

Premium, mid-grade and regular are merely marketing tools used by the petroleum companies to try to get you to buy a more expensive fuel than you need.

Ok. I'll jump in, Premium (most of the time).
Couple of myths, is it true if you run Premium your engine with become accustomed to this and will perform poorly on a lower octane ?
If you purchase Premium from a pump with one hose and three different octanes and the person in front of you just purchased 87 octane are getting 87 for the first say, quart or so?
Mike

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Couple of myths, is it true if you run Premium your engine with become accustomed to this and will perform poorly on a lower octane ?

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Not true, with this caveat; If you use higher than needed octane long enough you will build up carbon deposits that will cause pre-ignition.

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If you purchase Premium from a pump with one hose and three different octanes and the person in front of you just purchased 87 octane are getting 87 for the first say, quart or so?

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Yes, up to 1/3 of a gallon in some instances.

engines cannot get acustomed to gas

Frank

I tend to use anything. Lately I have been using low lead Av Gas which burns at about 100 to 120. I have had no problems. I use it because I was given it for free. It is semi recycled but very clean. I do alternate frequently but I have been using this stuff more because I kept forgetting to stop at the servo to re fuel

Gas guy told me there is no such thing as mid-grade. They only have two tanks, prem and reg mixed to get mid grade. Its not 50/50, its something like 60/40.

If the engine runs on 89 without pinging, (it probably will unless there is a lot of carbon buildup) there is nothing to gain by burning anything higher. If there were still vehicles on the road that used 68 octane, 91 might cause exess carbon formation and maybe even shorten exhaust valve life in them. With modern engines and "gasoline", the spread is less than 4%. Not wide enough to cause a lot of trouble as long as you use a high enough grade.

I think Greybeard said all you need to know. The word premium was coined many decades ago and means nothing in regards to whats best other than the price is premium. Different grades for different purposes. Lower grades are better for performance and probably for cleaner burning. The only reason not to go with lower grades is if the engine pings or doesn't run right with it. Then you go to the next highest. i think Triumph has nothing to gain by telling you to buy one or the other so i'd listen to them. I use 89 and have tried the lower and higher grade w/o noticing anything i could be sure wasn't placebo effect. So i'll listen to triumph in this case because unlike some things they have no finacial interest in what gas you use. so i'm sure they'll tell you the truth, and if anyone knows best about triumphs i would thing the people who built them would. Now if you wanna talk oil.......well, they DO have an interest in that and therefore i tend to listen to my common sense more than thier hype.

I started useing the regular low octane gas when I last changed my oil, about 3500 miles ago. I do not ping, the bike has been running good. As a matter of fact, this bike runs better than it ever has before. The only mods I've done has been to rejet, and replace the stock pipes. The bike has never been to any other shop since I brought her home 2 years ago. Seems like as the miles increase the better she runs. Running regular gas I've crossed Death Valley at 85 miles per hour, and just last week, comeing down Hwy 395, out of Bishop we ran between 95 and 100, keeping in front of the SUV's all the way to the California City cutoff. I have not noticed any difference in running the regular gas.

I had to use Premium in my old '71 trophy but mostly I use 89 octane in my TBA. I've used 85 through 93 Octane and cannot tell the difference. I use 89 most of the time becuase that is what is reccomended in the manual.