100 octane or 91?
 

Which is better for the superhawk, 100 octane or 91? And why? Found out I have a gas station local that has it

87 because that is all it needs unless you like spending money for nothing ;)

Agreed.

To high of octane can actually hurt performance rather than help. All you need is 87 and it will run great. The octane rating is a scale of the fuel's resistance to combustion. The higher the rating the harder it is for the fuel to combust. This is needed on high compression engines as the high compression can create enough heat to ignite the fuel and cause detonation and/or preignition. Having to high of an octane fuel in an engine can actually hurt performance in that it won't burn as well.

What they said.....

Funny thing is my bike runs like crap on low octane fuel. Run the good stuff and you'll be happy. It won't hurt the performance as some will suggest. There are other benefits to running higher octane fuel too. Just do it, your bike will thank you for it.

I had ran 100 octane in my hawk, the 76 station in the next town over has VP at the pump ($9.05 gal) didn't really notice any performance changes. only time i ever felt any performance changes from fuel was when i got gas at AMPM, bike didn't like it at all. went back to shell and everything was fine. All i put in is 87.

I know 100 is definitely a waste but have always put 91/93 in my bikes. Maybe I should only be using 87?

So, to spin off of this, how about the lower 85 here in the high country? I would like to save that extra few cents a gallon, but I don't want to hurt performance. If the manual clearly states 86, I don't see it being that drastic of a change to go up or down by one point?

I have rejet my carbs to 172/175 main jets.
~Jon

Honestly, You should just run 91 octane. 100 Octane is basically like race gas, and its so high that I don't think the bike can actually appreciate it. On CARS, having that in a turbocharged vehicle will increase the performance a lot. On bikes, I think it might just be a annoyance.

I'd personally run 85 in high elevation unless it was causing problems.

No. Run the premium - your engine will thank you for it.

unless the computer can sense the type of fuel being used, or would have the ability be programmed to adjust spark to take advantage of the extra octane the difference will be nil...and there will be no performance gain by using the higher octane fuel.

If the manual calls for 87 octane, i'd use it...some cars will have a blurb that says "minimum octane 87 but performance can be increased with higher octanes ratings). I know my VW Jetta says something very similar. Turbocharged or supercharged engines running boost will require the higher octane to prevent pre-ignition and detonation, or engines with excessively high compression ratios.

From now on I am only going to run the 90 octane RV non ethanol since I can again.

Jamie, why is this? From everything I've seen and experienced (in my little world), premium gas adds no benefits to lower compression (and lower tech) motors. I'm admittedly not an expert at all, but have not been convinced as of yet...

^^:bs:^^

GTS is correct, period. Guys, do some serious research if you don't believe it. Seek the truth, it will save you money! Higher octane fuel isn't the better stuff.


Start here.

"It may seem like buying higher octane “premium” gas is like giving your car a treat, or boosting its performance. But take note: the recommended gasoline for most cars is regular octane. In fact, in most cases, using a higher octane gasoline than your owner's manual recommends offers absolutely no benefit. It won't make your car perform better, go faster, get better mileage, or run cleaner."

:bs2:

Support that statement.

Here is some more good reading for you. E15 and Engines - Can Ethanol Damage my Engine - Popular Mechanics

Brothermike, not quite sure if you're just pointing out that ethanol is bad (it is), or that you should use premium. In Phoenix, and most areas, they put ethanol in everything. I'd have to ride about 30 minutes out of my way to find a station with ethanol free fuel of any sort.

The 90 octane ethanol free that you suggested is good for your motor because it is ethanol free, not because it is 90 octane...

You sir are correct, our bikes were not designed to run it, so if you must, keep the tank full, do'nt let it sit for more than a week or so without running it or winterize it,If I could get it in 87 I would. Before Florida Repealed it's 10% mandate I would take a can to the nearest station that had it when ever I was going near the station. The only downside is the price which is $1 more per gallon ,so I guess I am trading money for time not spent rebuilding the carbs, fuel lines ect.
Wow your not kidding it is hard to find in AZ.






Ethanol-free gas stations in the U.S. and Canada

91 is not "better"

But using the grade of local fuel which allows NO pre ignition is the goal.
For me, in my part of Texas...selecting 93 octane is the only way I can consistently fill with fuel that does not cause pre ignition (detonation)
Those who blindly fill with the lowest octane they can buy because a service manual printed in Japan 20 years ago says run 87 Oct are as foolish as the person that selects Premium because it's needed for "performance gains"

Saw a special on e-free gas a while ago. There are cheap test kits you can buy to verify it's actually e-free. I suggest you look into it. All the stations in this piece were advertising as free but actually weren't. All blamed their supplier. It said it is very difficult to find actual e-free gas.

Thanx, found it and I am ordering it ;) I can not tell you how pissed I will be if I am getting duped.

I agree. Living in a country where we face brutally cold temps in winter, running high octane gas is futile. Summer when it's hot, and your engine
needs the extra octane if you run a high compression engine...OK. Running it when it's 5°F, you're probably hurting the engine more then helping it. Ambient air is so cold, it contributes to the octane factor, and,
fuel burns even less. Consequence of this, cylinders get washed by un burnt fuel removing what the oil is trying to do, lub the cylinder, causing premature engine damage in the long run. It also ends up clogging catalytic converters(if this applies).

Agreed. Even after a carb sync, my 'Hawk would "hiccup" once-in-a-while, which is actually a little unnerving whilst traversing a round-about. When I pulled my fairing to replace my steering neck bearings, I noticed the sticker that says "91 octane." I've started using it and have noticed a huge difference in the hiccuping. Also, anything under 91 octane (at least in my area) contains at least 10-percent ethanol. Yes, some of the high octane stuff does too, but I don't buy that ****, I ride to the next station that sells ethanol free premium. I'm not paying 4.35 a gallon for corn juice.

;) Agreed

Erik, I run 87 even in the peak of our heat, which can be 90-95ish w/ high humidity. I have never once had any signs of pre-ig knock. Just my experience.


Thank you! Well said.

BrotherMike, let us know the results when you test it.

VTArh, pics or it didn't exist. I've had the occasional carb fart, definitely not pre-ig though. Are you sure it wasn't a miss or said fart?

But you're in Wisconsin! You should be proud of the corn juice.

I agree to one point... if you find the bike runs better (less hickups) with premium, then use it. I have not found this and my 3rd party research has indicated that my real world findings are not invalid. Jamie has a lot of knowledge under his belt so I would not discount what he says, I just haven't personally been convinced.

The only reason I can possibly think of not to use 87 or 89 octane is that the crap ethanol evaporates and lowers your actual octane rating when it does.

Gasoline
 

Seen all that has been said .. the lowest octane fuel we can get in the UK is
95 ... and super at 97 all is much the same.. unleaded gas of course.
There is no difference in performance I can measure in my VTR firestorm
in any fuel..:)
Alb

The biggest differance between UK fuel and US fuel apart from price, is the Ethanol content we have very little in comparison. Not for long though if things keep going the way it's going. .eek

(:-})