solo500

The manual recommends 87 octane, although I have used premium fuels before. Is it better, is there no difference? I've been using the 87 because someone told me it makes no difference. What are your opinions? Does higher octane really mean more combustion?

QWKYNUF

If your engine is stock, meaning you have done no modifications that would increase compression ratio:
Cam
Higher compression pistons
forced induction
drove like a granny for 10 years until you have huge carbon build up on your piston tops

or mods that would change your ignition timing:
Tuner

There should be no reason at all to run Premium fuel on a stock engine unless you really feel that the oil company executives just don't make enough money.

The oil companies would like for you to believe (though if you listen carefully, they never actually SAY it) that Premium fuel is "better" for your car, that your engine will run "cleaner" on it, and make more power.

This is BS.

Octane is not a measure of energy value. it is not related in any way to how much energy is produced. Octane is a rating of a fuel's resistance to burning - that is not a typo.

A chemical called Heptane is added to fuel to make it harder to ignite, increasing it's octane rating.

Why would they want to do this?!?! Wouldn't we want the gas to burn as readily as possible???

Actually, no. We want the gas to burn when we want it to burn - after the spark plug ignites it. Gasoline is extremely voilatile. You r air/fuel mixture could easily be ignited before the spark plug is ready to fire - by a tiny piece of carbon in your combustion chamber still glowing red - or, more commonly, the mixture can be ignited just by the heat generated by compressing your air/fuel mixture to around 1/10 if its original volume (like a diesel)

These conditions cause what is commonly known as 'pinging' or 'detonation' - which is literally the sound that is made by a cylinder firing before its turn in the firing order.

Higher octane fuel can help overcome these problems.

Ok, so why do racers use high octane fuel? Doesn't it make more power?

Typically, racing engines have been modified to make more power - and since an engine is nothing more than an air pump, there are only 2 ways to increase the power output:

make it more efficient, so it wastes less power - removing restrictions in intake and exhaust

run more air through it - lots of ways to do this - forced induction, changing cam lift and duration, larger valves, increase displacement by boring or stroking (actually, forced induction is really just an artificial way to increase displacement)

Many of these things will cause or contribute to detonation - high octane fuel is necessary in these instances to keep the engine from blowing itself apart..

Now all that being said, I doubt that anyone who has an opinion on the what is the "best" gas to run is going to change their mind because of my ramblings, but I stand by the accuracy of the information.

Interestingly, when I bought my Gold Wing, I ran strictly premium in it because I figured it must be better, and it only made a few cents difference in the cost of filling up the 5.5 gallon tank. After about a year, I was looking for something else in the owner's manual and ran across a paragraph that said that the manufacturer recommended 87 octane fuel. I switched , and have since put more than 60,000 miles on the bike. Running premium (91, sometimes 93) I averaged 40-41 mpg. Since switching to regular, i consistently get 44-45.

The moral of the story is that the manufacturer of your engine probably has a good idea of what was best for your engine when it rolled off the factory floor.

Anyway, I hope that explanation helps clarify things a little.

QWKYNUF

solo500

Thank you so much, you have cleared up a lot of things I have been wondering.

Ken Rogers

That's really interesting stuff, thanks for the write up. I've also been told that all gasolines have cleaners in them, so you don't need to spend the extra bucks for super-duper cleaning.

Ken

Goliath

if you're asking stock, anything past 87 octane is a waste of money. If you're talking bout running NA modded (serious stuff, not bolt ons, most of these are bolt ons), only if you're an ET junkie. The difference is negligible without FI or serious modding.

HurricaneStang

I always put super unleaded in mine just for the fact its usually 5 cents a gallon cheaper here plus i like the super in the name

orion6g

what about CAI, exhaust & a tune, would that warrent higher octane?

rygenstormlocke

Yes, if your tuner tuned the car for 93 oct.

rex7010

Yes I MUST run 93 fuel in my car because that is the way my "tuner guy" set my car up ..

but before that.. I ran 87 everytime.. even your owner's manual will tell you to run 87..

yes I know the gas cap says to use BP fuel only .. but we all know FOrd and BP and getting a "kick back "

from each other for that.. lol


take it for what it is worth..


Rex

petepete

before i supercharged i used premium anyways because 50 bucks to fill up once a week really sint much like 250 a mont h in gas not really that much even it was 10 bucks a gallon it really wouldnt be that bad bu thats just me