What fuel?

[Latte]

Out of interest did you know formula one race rules require that the cars run on maximum RON 91 and it has to be pump gas with no additional additives. Your bog standard bikes are most likely only needing 91 if you are really keen on demonstration any improvement gained on you bike from altering the fuels book some dyno time, run the bike on 91, 95 and 98 making no alterations and see how much benefit or gain you get from the higher octane.

Then you will be able save the money you spent on the dyno time by using the correct fuel and not paying up to what 15 cents a litre extra for you fuel, might take a while unless of course you want actually get out there and ride.

There is plenty of good info on the net about this subject written by some very bright minds.

+1 - if your motor is tuned to run on 91 then it may infact lose performance running a higher octane. It was my understanding to use higher octanes when using 91 would cause pinking/detonating as the higher the RON, the slower the flame front for combustion (similar effect to retarding ignition). Manufacturers would recommend a minimum ROM to help prevent detonation.

[GOONR]

Really, what year is it?

I haven't tried 91 as I was told to use 95 or 98. Seems to run ok on those.

It's a 1997. Yeah it's just not as smooth running with anything else in it, coughs and splutters a bit.

[avgas]

^^^^^^^^^^^^

[JMemonic]

+1 - if your motor is tuned to run on 91 then it may infact lose performance running a higher octane. It was my understanding to use higher octanes when using 91 would cause pinking/detonating as the higher the RON, the slower the flame front for combustion (similar effect to retarding ignition). Manufacturers would recommend a minimum ROM to help prevent detonation.

Pinking/Detonation is the other side of the equation when the octane is not high enough and the ignition of the fuel occurs before the spark fires to ignite the fuel air mix which is why some engines need the higher octane.

You are right though in your understanding, when the compressed mixture is ignited by the spark there is a controlled burn. The time that burn takes in the cylinder gives us our power, potentially if we have an octane rating that is excessively high the burn rate will be to slow, you can have a situation where the fuel is still in the process of burning as it is being pushed out of the exhaust valve which of course could damage the valve and is really a total waste of the power from the fuel.

Now if I remember my tech lessons from 20 some years ago the difference between 91 and 95 is not likely to have this occur to the full extent but you do have potential to lose power, however going from 91 to 100+ has potential for this effect to be noticeable.

Good to see someone is actually thinking about this, not that you will really educate the masses and nor should your try, oil companies have spent billions on advertising to "educate" the public that their product is the best and that higher octane means higher power from all engines, in all honesty there are very few road cars that need 98 octane and even less bikes.

[Jonno.]

Older bikes with worn needles/jets may require higher RON fuel as they'll be running slightly richer than a newer bike. CV carbs are more prone to wear as the needles tend to vibrate.

My FZR runs better on 95/98 but the major thing is on cold starts it will idle better.
Different fuels have different octane ratings and additives, the RON figure is only is resistance to pre detonation not the ration of octane.

Higher octane doesn't have less fuel in it.

Basically: if your bike says to run on 91 anything more is burning money.

Most improvements are placebos.

[Will the ninja]

I've been changing fuels for a while and here are my findings. The bike is made to run on 91. It doesn't knock and runs the best on 91 (as in it feels faster), but mileage is the worst - averaging 20-22K's per Litre.

On 98 it runs smooth as well. But it feels like it takes longer for the engine to accelerate (just very slightly). However mileage is the best - averaging 22-25K's per Litre. As I commute, that is enough to justify the extra dollars. $2.50 for 50-75 extra K's per tank is worth it I reckon.

What are peoples thoughts on Pump Station Brands?

[GSF_Lou]

This is an interesting thread. When I bought my bike the dealer said he thought it seemed to run better on force 10. Unless he has shares with gull I highly doubt he was trying to bullshit me. I know when it comes down to tuning, you are able to pull more power out of force10 than BP 98 but as the bike isnt specificaly tuned for it (to my knowledge) should I really be running it?

[Gremlin]

Depends on bike, compression etc as already said. Hornet is completely happy on 91. KTM, being a euro bike should ideally never run on less than 95, and all the tuning has been done on that. Still, she gets good consumption on 98 as well. Ethanol fuels should be treated with caution. A bike not designed to run on it can have fuel lines eaten away etc, so I avoid. Brands? Seems to vary on bike, some seem to like one more than another. I fill with a lot of shell at the moment as it seems to give good results.

[sapperj]

98 perfered, 95 if no 98 on pump

[Hiflyer]

91 cos it's the cheapest!

What are peoples thoughts on Pump Station Brands?

TBH after some quick research last year, there is sweet F.A diffrence between the various petrol station "Brands"

Caltex's fuel is "SCIENTIFICALLY PROVEN TO CLEAN YOUR ENGINE" but if you read up about it, it's a tiny difference.

Shell's fuel "TAKES YOU FURTHER", yea it does, by 2-5%, compared to the other brands.

Dunno what the fuck Gull does, they just sell it and leave it at that I guess.

I reckon the difference between suppliers is not enough to warrant only going to that particular company.




Just go to the one that put their prices up last...

[SMOKEU]

in all honesty there are very few road cars that need 98 octane and even less bikes.

I thought it would be the other way round, seeing that bikes often have higher compression ratios than NA cars.

[scumdog]

And you think that's bad, my 2L car drinks 40L of fuel in 250km without even going over half throttle.

Pah!

My Thunderbird gets only get 200km on 45 litres

Anyhooo...back on topic...my F100 NEEDS 98 octane as it's 11:1 comp.

The bikes? 95 in all of them.

[Suntoucher]

91 cos it's the cheapest!









TBH after some quick research last year, there is sweet F.A diffrence between the various petrol station "Brands"

Caltex's fuel is "SCIENTIFICALLY PROVEN TO CLEAN YOUR ENGINE" but if you read up about it, it's a tiny difference.

Shell's fuel "TAKES YOU FURTHER", yea it does, by 2-5%, compared to the other brands.

Dunno what the fuck Gull does, they just sell it and leave it at that I guess.

I reckon the difference between suppliers is not enough to warrant only going to that particular company.




Just go to the one that put their prices up last...

Gull is all Ethanol blends, up to 10%, assumedly about 5ish depending on ethanol cost at the time.

[Nzpure]

Your all assuming that what it says is actually the octane level. I have been really into performance cars, reading up bg anything that may get you a extra 5kws or extra 8th of a second and one thing that became apparent very quickly through all of the information I read through he octane rating may have been 98 at one stage but by the time it gets tob your car/bike it's more closer to 95 and so forth. So unless your bike is pinking or your running boost stick with 91. Mind you that's just my 2c's worth.

[Gremlin]

So unless your bike is pinking or your running boost stick with 91. Mind you that's just my 2c's worth.

It does depend on the compression of the motor. The sportsbikes are usually a high enough compression that they wouldn't be happy on 91. Also common for the European bikes (KTM, BMW etc) to also want a minimum of 95 RON, and would prefer 98.