which octane should i use? 1500 vulcan

[zuke]

i have a vulcan 1500classic... 98...

i just purchased it a week or so ago, it only has 10k on it, but it seems i get really bad, or relatively bad gas mileage...

some of the guys at work say i should be running the higher grade/octane fuel instead of the 87 octane...

so, will running the better fuel help me out?


thx
zuke

[jonnythan]

i have a vulcan 1500classic... 98...

i just purchased it a week or so ago, it only has 10k on it, but it seems i get really bad, or relatively bad gas mileage...

some of the guys at work say i should be running the higher grade/octane fuel instead of the 87 octane...

so, will running the better fuel help me out?


thx
zuke

No.

[slimcolo]

87 is the higher octane (mid grade) 89 oct (super) is usually avail if you look hard. I usually run the higher oct (87) mid grade rather than regular. Seems to stop the pinging on Hack, Sporty, 75 BMW and Vette. (all except Vette are points) Does not seem to make any difference on others!

How bad is your mileage? My FLH sometimes drops to 18 or 19 in city, but gets 42-46 on hiway, Sporty 32 city,54 hiway. In high school I had a Dodge that got at best 7mpg, but my Dad got 23-26 with same car. Might be your driving. And again maybee you just need a tune up!

[jonnythan]

87 is the higher octane (mid grade) 89 oct (super) is avail if you look hard. I usually run the higher oct (87)mid grade rather than regular. Seems to stop the pinging.

Uh, here, regular is 87, mid-grade is 89, and premium is 91. Some places have a 93 super-premium.

This is the case for all the states I've driven in. 40 in total.

[slimcolo]

Uh, here, regular is 87, mid-grade is 89, and premium is 91. Some places have a 93 super-premium.

Must be nice, and must be a Eastern thing. Reg here is 85 mid is 86.5 or 87 prem has been max of 89 since the switched to unleaded. I'm in Colo and it's the same for at least parts of Wyo,Mt,Ut,Id, and Northern NM. The gas companies say its an altitude thing but in Lamar,CO (3600ft) they sell 85 reg, and in Lead,SD (5300ft) they sell 87 reg

[jonnythan]

That must be a Colorado thing, because I've driven in California, New Mexico, Oregon, Washington, Montana, Wyoming, and South Dakota. I've never seen 85 octane, much less a half-octane rating like 86.5. That's just weird.

Also, both of my cars have recommended "standard 87 octane" gasoline, as does my bike.

[jonnythan]

Ah-ha.

It's an elevation thing.

"In most parts of North America, you should use unleaded gasoline with an octane rating of at least 87 AKI (Anti-Knock Index) number. However, you may use unleaded gasoline with an octane rating as low as 85 AKI number in these high altitude areas [over 4,000 ft (1,219 m)] such as Colorado, Montana, New Mexico, Utah, Wyoming, northeastern Nevada, southern Idaho, western South Dakota, western Nebraska and that part of Texas which is directly south of New Mexico."

Depending on how high you are in the Rockies, you'll find regular with ocatane ratings of 85, 85.5, 86, or 86.5 with other grades have a corresponding decrease in their numbers.

My brother lives at over 9,000 ft and I've never had any problem in the 20+ years I've been visiting him, coming from an altitude of less than 1,000 ft. In fact, with all of the different cars I've owned, I've always gotten some of the best mileage with 85 octane while crossing the Continental Divide four times."


"In the Rocky Mountain (high altitude) states, 85 octane is the minimum octane and 91 is the maximum octane available in fuel. The reason for this is that in higher-altitude areas, a typical combustion engine draws in less air per cycle due to the reduced density of the atmosphere. This directly translates to reduced absolute compression in the cylinder, therefore deterring knock. It is safe to fill up a car that normally takes 87 AKI fuel at sea level with 85 AKI fuel in the mountains, but if carried back to sea level the fuel may cause damage to the engine."



http://www.montanagasprices.com/Forum_M ... o=10&FAV=N


In the lower elevations in most of the country, the standard grades are 87, 89, and 91.

BTW, the octane number of the gas is simply its resistance to knocking. Higher octanes are required for higher-compression engines. Higher octane fuel actually has *less* energy per unit and gives *poorer* gas mileage. The absolutely only reason to use a higher octane is if the lower octanes cause knocking.

[slimcolo]

Probably is Colo thing. In Id and Mt just a few stations and that was 5 years ago. The other States I mentioned were stations close to Colo line and may get gas from Colo. (one of them in NM I'm sure does, there is a refinery in Western Colo that's 18 mi from Utah line)

As for Owners manuals my 72 Harley says do not run alcohol, do not run un-leaded fuel and run at least 105 Octane. (you couldn't even hardley get that in 72)

[flynrider]

Zuke,

Your best bet is to use the octane that the manufacturer specified. There are several factors involving the engine design that determines the type of fuel that should be used.

If your engine is not pinging under load, a higher octane fuel is not going to do anything but empty your wallet a bit faster.

[mydlyfkryzis]

If your Owners manual calls for regular (87 octane), you may even get less mileage with a higher grade.