correct! SO many people think higher octane = more power...only if compression/tune needs it! I laugh at when people with an otherwise stock vehicle that say "i put race gas in it and its so much faster!" Now in one of my (turbocharged)vehicles I have 2 different tunes-pump vs race gas with the flip of a switch compensating for timing/fuel and different boost into motor it makes a BIG difference (400whp to 500+whp) but the race gas isnt giving me more power its just keeping the 1.9liter from blowing up when I turn the boost up to a level higher than where pump gas can suppress the detonation!

 

I still run 89 in my Lo Boy unless it's over 80 degrees, which is most of the time. Never run anything higher than you need to.
save it for

JMHO

 

This debate goes on and on but I agree with the posts above. For stock engines, use the octane rating recommended by the manufacturer. For my bike, it's 91. No benefit in using 93. JMHO

 

SEARCH WWW FOR ETHANOL FREE GAS. SEE THE SITES IN ALL STATES THAT HAVE NO ETHANOL. READ THE HAZARDS OF ETHANOL.

 

Just had this arguement again a few weeks back with someone claiming how much quicker their car feels by using 93 octane vs the 87 the manufacturer recommends. Couldn't make them understand that the 93 burns slower than the 87. They always come back with, "So why is it more expensive?" and, "Why do they call it premium?". Gives me a headache.

 

There are exceptions to every rule. Your buddies car may have indeed run better with the higher octane, perhaps because of the state his tune was in. Don't be surprised if he's offended by you calling him a liar.

Yes "in theory" it burns slower. But there are factors that could be goin' on where his car "felt" better with the higher octane.

I've seen both scenario's over the years of experimenting.
Sometimes no difference, sometimes there is a difference.

Don't go disputing **** unless you are driving the car in question.
Human nature. Call somebody a liar, he gets offended.

 

I have a gas pump like that a block away from my house. I have never had an engine yet that has needed the 100 octane. Unless you are over 11-1 compression I would steer clear or you will be losing power from the slow burning fuel. Im so glad there isn't some idiot claiming that it runs hotter the higher the octane rating. I always hated that argument.

 

the race fuel here is 100 and 110 both have lead as a octane booster that mybe what got your o2 sensers.

 

I'm looking at this thread because I just put about 1.2 gallons of 101 octane in my Iron on top of the 91 that I usually run. (Would make it about 97 octane)
((I only have an intake and V&H short shots, no tuner of any type yet.))
I was surprised to see that a couple miles down the road the bike started acting different. At idle I noticed it sounded like a much lower RPM, which made it sound loppier, then take off was dramatically slower and I had to give it way more throttle to take off. Low end torque suffered noticeably, and top end may or may not have benefitted, if it did, it was marginal.

I will not be trying 101 octane in my bike again until 'maybe' after some tuning. And it makes me second guess the 91 octane I normally use.

Edit: Best way to think of different octane, is adjusting your timing. Essentially that's kinda what it does.

 

The old rule of thumb that I know is that if you try it and the bike runs better,smoother, faster that it is not tuned properly or (lean). If it stutters,stumbles and has less power you are tuned properly. Correct me if I'm wrong?