FZ6 on Race Gas!

[bmccrary]

A bit of a sales pitch but the end is not too bad
http://www.rockettbrand.com/techsupport/documents/TechBulletins/100VsOctaneBooster.pdf

Overview - Sunoco 260 GT100 Locations

That link takes you to the type of fuel that was put in.
Purchase in Charlotte, by Concord Mills.

Ok so far thats it to my research...

-bryan

 

[opds9091]

According to the 07 FZ6 Manuel, your Yamaha engine has been deigned to use regular unleaded gasoline with a pump octane number [R+M)/2] of 86 or higher, OR a research octane of 91 or higher. That is in the owner's manual under INSTRUMENT AND CONTROL FUNCTIONS, sub text FUEL, under chapter 3, page 3-11 &3-12.
just my 2 cents i always use the highest they have.

 

[Doorag]

Those of us in the UK can run 97 all the time if we want. :rockon: :Flip:

 

[tuningfork]

I have always known that the higher the compression ratio the higher the needed octane. It has always been to my knowledge that the good rule of thumb is that anything much over 12.5:1 is pretty much in need of octane higher than 93. 13:1 really being the major line.

But with the compression ratio on the 2009 FZ6 being at 12.2:1 as noted on Yamaha's site. (Assuming they havent adjusted that since the release in 2004 or 2005) A higher octane would be of some help rather that hurt. I am not sure what the C.R. is on your outboard or atleast I may have overlooked it, but I would assume is lower than that of the FZ. Seeing as how the motor has to last longer at extreame conditions, ie W.O.T for extended times.

I am currently taking Thermodynamics 1 and I am starting to learn about pressures and such of various gasses and conditions so I imagine I will learn more about this topic as the semester goes on.

As in regard to heat, the temps of the bike were warmer than what was expected. I was running highway for a while in lower 70 degree weather which in the past has always kept the bike in the 2bar range in coolant, esp at highway speed. (I wish the bike had an actual degree read out over that bar system.) However, that night I was running 3bars.

I have always heard that due to the higher octane that the burn is hotter and is a more even burn do to the higher refining process.

It would make since that with this more \\"pure\\" substance that it would ignite quicker and faster than lower grade. This would cause more burn on the intake valves and could be adjusteded by retarding the spark a touch. However, too much retard would put excessive strain on the valve train and would risk failure there.

(But on a side note, to those that are reading this.... this is how, to my knowledge a two step works on a car. The retarded spark timing alows the fuel to ignite late and puts more heat out the exhaust to help spool a turbo/turbos :Flash: with out a load.)

I do not understand how a more refined fuel will leave more deposits on a motor than that of a less refined fuel?

On a lower compression motor I could see where the higher octane would cause a inverse effect on power and could create the poor throttle respose. However with the semi high C.R. that the FZ motor has, I really doubt it is hurting it any. But like I said in the original post, I am sure that with more tuning and better electronics/software it could take full advantage of it.

I will do some research later on. As for now I have to find a mounting point for my new horn. \\"139db of ear piercing goodness\\"

-bryan

in really simple terms, the deposits can build up because not all of the fuel is burned and/or the resultant flame temp is lower. There are relationships between air/fuel ratio, octane, and spark timing which affect the burn speed of the air-fuel charge. On a 2005 which has fixed fueling and timing maps, by adding a slower-burning fuel there will (may?) be some that does not burn...so you may have wasted "charge". The 2007+ O2 sensor may be able to detect some of this change and adjust the fueling, but the timing is still fixed.

If you are searching around look for terms like "flame speed/propagation".

In general you want to run the lowest octane that doesn't knock, this means you are making the biggest/hottest bang (that is still a controlled burn).... which will cause the greatest thermal expansion....which pushes the hardest/fastest on the piston..... which makes the most torque.....which translates to most HP. The speed and timing of the burn can affect the resultant power output...reach max pressure too late and the piston is already moving down, too early and you are firing into the piston, slowing it down.

best analogy is to think of pushing a kid on a swing...if you time the push too early or too late they don't swing as fast or as high. get it just right and you get a big return on your push.

now if you have access to remapping air/fuel and timing you can remap the bike for premium and may see benefits....most likely you will lean it out in spots and add some timing advance.

This all assumes the factory "got it right"...if their tuning was wrong then changing fuel may result in better operation.

If your bike was running hotter it could have been too rich or too lean before.

My experience when tuning my FZR600 was that the lower octane burned hotter.

Maybe you should try to source a 2007+ cluster...there is digital coolant and IAT available on the display

 

[PeterK]

The octane of normal unleaded fuel in the UK is 95 RON, super unleaded is 98 RON. 98 RON cost slightly more, but I din't bother. Is there a specific reason for such low ratings in the US?

The ratings aren't low, they are different.
You use RON, we use (R+M)/2.