Now I might learn something new here. You have got me intrigued. If higher octane means LESS flamable - which based on concept I can comprehend - more parts oxygen and less parts fuel. Why would performance motors want higher octane fuels? This is assuming we're still talking about gasoline and not getting into other forms of fuels. Maybe the better question is where does fuel octane come into play with the combustion process? This may be a less educated thought but I guess I always assumed more octane, more power. Am I wrong?
Hi output motors have much higher compression ratios. The higher the compression ratio, the closer you get to the limit of pump gas.
What happens inside your engine is that your spark plug fires before the fuel and air mixture is fully compressed. This is called ignition advance. So what happens is you can dial in ignition advance up to where you get pre-detonation. OR you can run compression high and up to the point of pre-detenation (Old school guys will call this knocking, or pinging). Knocking, pinging, and predetonation can occur for a few reasons, but all result in a knock, or an explosion that occurs prior to the fuel being compressed fully..
In extreme situations like boosted scenario's, you have to run race gas, higher octane, less flammable fuel to allow the motor to not detonate. A combination of lower octane race gas and a somewhat std guideline of timing RETARD per PSI will get you the most power without pushing towards detonation.
Too much detonation can put a hole in the top of your pistons.
So you are/were wrong. More octane doesn't result in more power unless you've done something to take advantage of this higher octane fuel (Like advancing ignition timing, or raising engine compression by thinner head gaskets or cutting/milling the head surface down for better "seating".
Hopefully this sheds a little light on this for you.
There is a difference in "slower burning" and "incomplete burning". Higher octane fuel actually burns more completely (efficiently) than lower octane ratings. So the term "less flammable" is a bit misleading.
You are correct in saying timing plays a huge factor in getting the most out of your chosen fuel. My point was that High octane fuel is "less flammable" because it is not...actually the opposite.
Savvy??
Yes, this sheds as much light as I can understand on the matter. There is a lot to understand and I'm happy to have learned something new for the day.
That being said, do you know the exact octane preferred for the 03 R6? Service manual says premium - which can vary between gas stations (90 - 93 octane).
There is a difference in "slower burning" and "incomplete burning". Higher octane fuel actually burns more completely (efficiently) than lower octane ratings. So the term "less flammable" is a bit misleading.
You are correct in saying timing plays a huge factor in getting the most out of your chosen fuel. My point was that High octane fuel is "less flammable" because it is not...actually the opposite.
Savvy??
you are correct for sure. I only say less flammable cause it makes much more sense when you read it. But yes, it's truly SLOWER burning, or technically has a higher flash point IIRC.
Ideally the contents of any fuel really shoud be inspected prior to diving into it!
Quote:
Originally Posted by Skitch
Yes, this sheds as much light as I can understand on the matter. There is a lot to understand and I'm happy to have learned something new for the day.
That being said, do you know the exact octane preferred for the 03 R6? Service manual says premium - which can vary between gas stations (90 - 93 octane).
Thanks for the lesson. I appreciate your help. Considering the octane booster I dumped in I think it is very likely this could be the cause of stuttering and lagged throttle response. I will probably at least check my min / max TPS values and make sure they check out. Thanks again.
Thanks for the lesson. I appreciate your help. Considering the octane booster I dumped in I think it is very likely this could be the cause of stuttering and lagged throttle response. I will probably at least check my min / max TPS values and make sure they check out. Thanks again.
Ignition advance increases throttle response. So if you've slowed up the burning of the fuel it very well could be your problem.
I was going to say, less flammable is a little bit off.... Maybe less prone to preignition from too much timing or compression.... But yeah, I would have to agree, Tdub.
It seems like we've had some pretty in depth discussions of octane rating on this forum before...... And what octane means and doesnt mean.
And really, you should be worried about more than just octane. Other factors include oxygenate level, how completely it burns, what temperature it burns, how well it atomizes, and so on. There is a lot more to a fuel than the octane number.
I was going to say, less flammable is a little bit off.... Maybe less prone to preignition from too much timing or compression.... But yeah, I would have to agree, Tdub.
It seems like we've had some pretty in depth discussions of octane rating on this forum before...... And what octane means and doesnt mean.
And really, you should be worried about more than just octane. Other factors include oxygenate level, how completely it burns, what temperature it burns, how well it atomizes, and so on. There is a lot more to a fuel than the octane number.
I remember going to Hangtown MX race a few years ago when it was 105*, back when RC4 was slaying everyone. We were walking through the pits and happened to run into an old friend who had some decent access to the Makita Suzuki setup. We got reasonably close to the setup and I was able to listen to a conversation they were having involving their fuel. Apparently, with the heat of the day, the humidity, etc, some of the characteristics of their fuel were creating major problems. Essentially, it had a low evap/boiling point and during motos the fuel in the tank above the engine was soaking enough heat that it was beginning to "boil" as they put it, making the bike not run correctly or not at all. They ended up putting a bunch of that reflective heat barrier on the bottom of the tank to prevent the problem. I had never even considered that such things could happen... So yeah, there is more to a fuel than octane.
you are correct for sure. I only say less flammable cause it makes much more sense when you read it. But yes, it's truly SLOWER burning, or technically has a higher flash point IIRC.
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