What octane

[jazzpaintball]

I have an odd question. I have been trying to answer this question for a while with the use of the internet with little success.

I am trying to figure out what octane to use. I was using 87 when my FZ6 was stock with no problems. I added the scorps on and I had went to a 92 octane due to the relieved back pressure making the bike run lean. The 92 octane of course was to try and compensate for the lean air/fuel mixture. Recently i got a PCIII for the bike (THANK GOD FOR THAT DEVICE) and got the bike back to a proper air/fuel mixture. Although with the mixture back up to par, do I (or at least can I) go back to a 87 octane? I would like to get a decent fuel-mileage and i know 87 octane will give me more power. I am just concerned with the bike having pre-ignition and ultimately having the spark plug turn into a torch-cutter in the higher rpms.

Anyone have any answers either from experience and/or tests?

Thank you,
Travis Walthall

 

[dako81]

Due to the squish design and compression ratio, I think you're fine running regular.

 

[Kazza]

Personally, wouldn't run any of our bikes on anything less than 98, but I'm in Australia and I don't know what your highest octane level is.

The extra money is well worth it. Looks after the engine a lot better.

 

[kpaul]

Personally, wouldn't run any of our bikes on anything less than 98, but I'm in Australia and I don't know what your highest octane level is.

The extra money is well worth it. Looks after the engine a lot better.

Generally you see 3 octanes here in the 'States: 87, 89 and 92. Perhaps the lack of variety is the price we pay for getting it so cheap, I've always wondered why other countries have much higher octanes. Maybe I should start refueling down at the airport with jet fuel.

As for the original question, I always put 92 in the bike, before and after installing the leos. A fill-up is only 3 - 3.5 gallons. So it ends up being less than a buck to go with the higher octane, and I don't see any reason not to spend the money to give my bike the best when I can.

 

[Dunno]

Generally you see 3 octanes here in the 'States: 87, 89 and 92. Perhaps the lack of variety is the price we pay for getting it so cheap, I've always wondered why other countries have much higher octanes. Maybe I should start refueling down at the airport with jet fuel.

Thanks for that. I wondered why it was mentioned as low as 87. I always use the 98 octane in my bikes.
About eight years ago I used to buy fuel from the local airport & run my bikes on avgas at the track. Awesome stuff :thumbup:

 

[zigzagg321]

I always use as high as I can get reasonably. Usually 93 is as high as you can find around here. There is a station about 3 miles from my house that sells Turbo Blue, supposed to be 104 octane. Ive never tried it.

 

[jazzpaintball]

So the 'as high as i can get' is used for your octane levels, but i am wondering about what the bike will run best with. It was designed for 87 octane, and i would like to be able to get the power boost with having the lower octane. I am just wondering, especially with the cooler weather, having the lower air/fuel mixture would be beneficial or not

Thanks again for the responses

 

[Kriswithak]

Yea I always get 98 here, because fuel in Australia is total crap.
You can literally feel the difference between brands, and some have to be avoided at all costs.
With that in mind we have heaps of E10 (10% ethanol) here, apparently because of the environmental benefits, which I won't defunc in this thread as being total political bs.
They are actually phasing out normal fuel and just having the E10, which is total **** in anything high revving, total **** in general, and ****......

 

[stink989]

thye differances in the different countries octane numbers are the way they are test i have been told so there is not much differece between everyones higest rating, or so i am told. Do not put that e10 crap in your bike car or even power equipment, i have talked to a small engines mech and he has mowers chainsaw etc come in contantly that are blown up as the ethonol seperates from the rest of the fuel and then has dedonation and melt pistons (in 2 strokes) and do all sorts of damage, the old man recons it kills seals and is just no good for your motor (he is a toyota mech) so i wont be touching that crap. Have heard stories of the sevos pulling the pin on normal ULP and just having e10 or premium

 

[Kriswithak]

Its probably a higher profit margin for them in some places, although here they are legislating for it. Some ignorant politician (think it might be the PM) seems to think that aiming to make fuel some huge % ethanol is the way to save the environment.
Again I won't go into why its not
Also most older cars are not build to use it, although the newer ones should be.
Personally I don't think pollies should have an opinion when their fleet cars are all 2.8+L v6s or larger

 

[yoshiki]

i am using 95 most of the time. what's available here is 92, 95, 97 (neighbouring country have 97 which is about 30km from my office)/98/premium (shell V-power).

 

[Dennis in NH]

I never chime in on these because "it makes no difference". Well, I used to run 89 and then I tried 93 and it felt like it made a difference. I ran 87 for a while (to use up some leftover gas from my generator) and it was good. I then filled with 93 and it was much better.

Could all be in my head but I'm going for 93 from now on.

I've got Scorpions too.

Dennis

 

[tuningfork]

This comes up from time to time but the method we use to calculate octane here in the US is different than most other countries. we use R+M/2 calculation, your typical euro country is using RON. 91 in the US is approximately equivalent to 95RON, 93 US equates to 98RON, etc.

I use E10 87 octane as well and the bike seems to run great, I average about 48 mpg. But I am 100% stock. I've never tried higher octanes.

If you have added a PC3 I would use whatever gas was in it when you had it mapped. If you had it mapped with premium I would continue to use premium. I would assume you could try running 87 again but I would have it remapped for that fuel grade. The differences in burn rate will have an effect on the AFRs/gas analysis and that will affect the tune. The bike will self-correct AFR to some degree if you are 2007+ but if you are doing a best-power tune I would use the lowest gas octane that doesn't knock....ie burn the most fuel in the combustion window = most heat generated = most force generated on the piston.

On my carbed bike I would see pretty big swings between fuel types and also when running E10 vs. 100% gasoline. Not a fan of E10 personally but it is better than MTBE which is a nasty carcinogen.

 

[champion221elite]

Generally you see 3 octanes here in the 'States: 87, 89 and 92. Perhaps the lack of variety is the price we pay for getting it so cheap, I've always wondered why other countries have much higher octanes. Maybe I should start refueling down at the airport with jet fuel.

Hmm... looks like tuningfork beat me to the post while I was looking up the info.

Here in the states, we use the (R+M)/2 method to compute the octane rating. Other countries use RON method which results in different numbers for basically the same fuel.

According to the web, the different octane rating models account for a difference of 4-5 points. For example, Regular Unleaded in the USA is 87 octane. That same fuel in Europe or Australia would be 91-92 octane using the RON method.

Here's my source...

Octane rating - Wikipedia, the free encyclopedia

 

[bcramer]

I use 87 Octane here in the states.

The bike was built for it and Yamaha recommends it.

The higher the octane the rating, the higher compression ratio a fuel can withstand prior to combusting.

The engine was built with specific compression ratings, etc and if higher octane fuel was needed or if it would help make the engine run better, I'm sure Yamaha would recommend it.

I'm bone stock, except for frame sliders

 

[RJ2112]

Use the lowest octane the bike will run on, without pinging. The only reason to run higher than the minimum specified octane is if you have increased the compression of the motor, and need more protection from pre-ignition. Turbos, superchargers, thinner than OEM head gaskets..... changing the muffler isn't going to affect pre-ignition at all. If you don't hear it rattling, or making a pinging noise....... it's bling.

A point of reference: Diesel fuel is much, much higher octane than gasoline. Diesels get better economy than gasoline engines because they compress their fuel/air mixture to ~ 40:1. Higher compression equals higher torque.

Controlling the point of ignition more precisely, is the sole benefit of running higher octane. Without any way for the ECU to know the difference between 87, and anything higher....... the ECU leaves the spark where it will run best for the specified fuel type.

As the engine gets older (much older than almost all of the bikes on this forum) more carbon will build up in the combustion chambers, which will decrease the available volume, and as a result increase the compression ratio.... this will happen due to the oil that enters the cylinders from the rings, primarily.

At that point, increasing the octane you use will limit the pre ignition that occurs due to the hot spots caused by the carbon...... but by that time it's probably due to have the engine torn down for new rings anyway.

 

[VEGASRIDER]

If there is a topic that has been beaten more to death, this would be it.

You could probably spend days reading the debate on which octane is better or best for the bike.

But here's a summary of what I have read over the past three years:

1. Owners manual recommends 87 octane because of our compression ratio. Might as well take advantage of the savings, why spend more if you don't have too.
2. Majority of the members use 87, but whatever you feel comfortable with, go for it, it's you're bike and you're money.

FWIW, I have always used 87 and I have over 40,000 miles on the bike. Look how much money I saved, enough to pay for a couple of mods.

 

[FrankieOC82]

This is an interesting thread to me because, although i've only had a few fill-ups since i got the bike, this last time I decided to try out the Premium octane after only running 87. I wasn't impressed really. Felt the same to me. I thought I would feel a lot more git-up and GOOO!!!!!, but i was disappointed. So I chalked this up to me not having enough years of experience on this bike to really be able to feel a difference. But this thread has enlightened me! If it feels the same to me, then I'm saving my $$ and going back to 87. I like the excuse to get more mods because of gas savings, too

Thanks to everyone for the info!!

 

[BusyWeb]

Am I too senstive ???
I could even feel differences on different brand of gas; shevron, mobil, shell, or etc..
And I could feel differences on different octane gases.
Here state So. Cal, usually has three different octane values; 87, 89, or 91.

87 and 91 difference is huge for me.
89 and 91 has just little differences but results goes differences on MPG.

Lower octanes gave me little rough riding feeling, but throttling is more sensitive than 91 ??
Strangly, 91 give little more delay time when I push the throttle?

 

[FrankieOC82]

HA, i would love to be that in tune with my machine!! I just think i need more time in the saddle before i get there. Practice makes perfect:rockon:

I think i do agree with you about the slight delay in throttle response with the higher octane. I thought i was imagining things and thought it must be in my head, sooo I'm glad to hear I'm not completely crazy!!