Octane

[KCF3712]

First of all, thanks to all who replied to my first post, I really appreciate the advice.

Now what about octane? I found a few gas stations in my area that sell gas w/o ethanol, and I've been using it for the past few months. What are ya'lls thoughts and findings about using higher octane levels to get the extra MPG? I'm currently using 87 octane.

Thanks in advance

KCF3712

[Patrick]

Unless your engine calls for premium fuel, you will get no benefit from it and it will just cost you more money.

[Lazarus]

Unless you are in Canada. The premium blends do not contain ethanol. Which could help mileage for some cars.

Ethanol blends: 10% in "reg." gasoline, 5% in mid-grade, 0% in premium (in Ontario)

Oops= Just saw you found some without ethanol. Depending on the car some will perform better without ethanol. If the higher octane is ethanol free then you could see a increase in mileage from lack of ethanol but not the octane.

[Creeper]

Originally Posted by Lazarus

Unless you are in Canada. The premium blends do not contain ethanol. Which could help mileage for some cars.

Ethanol blends: 10% in "reg." gasoline, 5% in mid-grade, 0% in premium (in Ontario)

Oops= Just saw you found some without ethanol. Depending on the car some will perform better without ethanol. If the higher octane is ethanol free then you could see a increase in mileage from lack of ethanol but not the octane.

Higher Octane would make a difference. Here in Canada we have 94 octane at some stations. While there is no Ethonal in most of the blends. The higher octane burns cleaner and better. I used to run it in my parrents 98 Astro V6 and noticed it performed better might be that it burns cleaner then 87. But unless your vehicle is being tuned for it or your running some performance mods which are only used on ocasion you might not notice much.

Whats the milage on your vehicle?

[Daox]

Originally Posted by Creeper

Higher Octane would make a difference. Here in Canada we have 94 octane at some stations. While there is no Ethonal in most of the blends. The higher octane burns cleaner and better.

Got any evidence to back that up? I've heard many claim this but have never seen any testing done to back it up.

I'd agree with Patrick that its a waste and is useless unless the engine is programmed to take advantage of it.

[Old Tele man]

octane is all about pre-ignition and detonation under load, and not about energy (BTU) content.

Thus, *if* your engine ECU (1) has "knock"-sensor(s) and (2) is programmed to dynamically adjust ignition timing, it is possible for the engine to "re-adjust" itself to "use" higher octane-rated fuel, meaning better power and response, but seldom better fuel economy if the BTU content is the same.

[cmj]

Originally Posted by Old Tele man

octane is all about pre-ignition and detonation under load, and not about energy (BTU) content.

Thus, *if* your engine ECU (1) has "knock"-sensor(s) and (2) is programmed to dynamically adjust ignition timing, it is possible for the engine to "re-adjust" itself to "use" higher octane-rated fuel, meaning better power and response, but seldom better fuel economy if the BTU content is the same.

Octane is for race cars. It allows for cooler combustion allowing more timing. The only benefit I see is the ability to add more timing, thus giving you a grunt more torque. I don't believe the gains in torque will help your FE enough to justify the higher price tag.

[some_other_dave]

It seems to vary from car to car, and possibly from driver to driver.

There is usually little if any MPG benefit from running higher-octane fuel. But in some cases, it does seem to make a difference.

In most of those cases, the cost difference per gallon is greater than the MPG difference, so it isn't worthwhile from a $$ standpoint. But there are a few people out there who have done what sounds like reasonably careful testing on their car and come to the conclusion that the MPG difference in their case was greater than the cost difference.

So far, I haven't seen any consistent pattern in circumstances that make it worthwhile. The only way to tell if it helps in your car is to try it and test very carefully.

-soD

[theycallmeebryan]

There are a lot of confusing comments in this thread.

First off, my Ninja 250 saw almost a 10% decrease in fuel economy between 87 octane and 94 octane. Take it for what its worth.

Octane is a measurement in fuels of the resistance to preignition. Octane rating has nothing to do with the BTU output of the fuel.

If your motor can run 87 octane without detonation, you will see NO benefit from running 93. (mainly naturally aspirated motors with low compression.)

[Old Tele man]

Originally Posted by theycallmeebryan

Octane is a measurement in fuels of the resistance to preignition. Octane rating has nothing to do with the BTU output of the fuel.

...exactly!