Just wondering why all race car owners run high octane pump gas or Sunoco or other race gas in thier cars, quit a few even run aviation fuel 112+ octane........hmmmmmm
87 octane sucks
- Thread starter mikeyusf
- Start date
Just wondering why all race car owners run high octane pump gas or Sunoco or other race gas in thier cars, quit a few even run aviation fuel 112+ octane........hmmmmmm[/QUOTE]
they are designed to run it. timing, valves, high compression, etc.
the bus is fairly high compression. under certain circumstances, altitude, air temp, etc, low octane, 87, can be hinderance.
for racing with a stock setup, you want to run a low enough octane, yet high enough not to detonate, but low for a quicker burn.
they are designed to run it. timing, valves, high compression, etc.
the bus is fairly high compression. under certain circumstances, altitude, air temp, etc, low octane, 87, can be hinderance.
for racing with a stock setup, you want to run a low enough octane, yet high enough not to detonate, but low for a quicker burn.
Correct Cache........just read this article.
Its long but informative.....and there's a few factors that are important besides octane.
There IS a difference in fuels - aside from the octane rating.
Different fuel blends burn at different rates under the same temperatures and pressures. Absolute fact.
Peak cylinder pressure, for best power output, MUST be timed to occur just after the top of the stroke.
To tune for maximum power, you would like to use a fuel that burns at the quickest possible rate - without "knock" (there - that covers pre-ignition and detonation) so you can initiate burning at the latest possible time and still produce peak cylinder pressure at around TDC. That way, the rising cylinder pressure pushes back down on the top of the rising piston for the shortest period of time - decreasing power lost there.
A more specific location for peak cylinder pressure would be ~15 degrees after TDC. There is some variance from that figure - but not more than a degree or so in an engine using gasoline. When the ignition timing is correct, power output will be highest for that rpm and throttle position.
(thanks, Al Cline!)
Octane?
If you look at the octane rating as only an indicator of what the fuel was designed for, you'd guess that a 120 octane fuel was probably designed for an engine that was prone to "knock" - like an older American V8 with relatively poor cooling and high compression. That fuel will be blended to burn at controllable rate that matches the high pressures and temperatures present AND resist "knock". A good match for those V8 engine conditions.
Burn Rates- That's the ticket!!
If you take that same fuel that worked well in the above V8, and run it in an engine, like a cbr900, with it's lower cranking compression and lower combustion chamber temps, it will, without a doubt, burn much too slowly at those lower temps and pressures and reach maximum cylinder pressure too far after TDC for best power.
Things generally burn slower when they are cooler and vice versa. Peak cylinder pressure will occur much past TDC - decreasing the power produced if you keep the same ignition timing.
You can advance ignition timing to try to recover power, but that will cause the air/fuel mixture to burn earlier in the crank stroke and spend, percentage wise, more of the energy produced by the expanding, burning mixture, pushing back down, trying to prevent the piston from rising up to the power stroke - robbing power.
If you MUST use a slow burning fuel, which USUALLY has a high octane rating, advancing the ignition timing will lessen the power loss, but the best results are usually obtained with the quickest burning fuel obtainable, that, of course, doesn't "knock".
All other factors being the same, except for burn rate - use the quickest burning fuel that doesn't "knock", light the spark in the middle of the combustion chamber, adjust ignition timing to reach peak cylinder pressure ~TDC and keep your mixture correct. When the ignition timing is correct, the engine will make best power for that fuel.
There is a difference in the burn rates of different brands of fuels that are available. Some compliment one engine and some compliment the existing tuning of a different type of engine. Our Supersport YZF750 was really responsive to different pump fuels and liked a different type of race fuel (same brand of fuel) than our gsxr750 Supersport bike. Something on the order of 1%-2% power difference.
Generally, the cbr900's are extremely power sensitive to different fuels. It has to do with the basic combustion design.
Does using a fuel with higher octane numbers automatically make more power?
Not unless they are preventing "knock".
My vehicle runs fine and doesn't "ping" on "regular" fuel, but, it's a little "peppier" with "premium" fuel. What should I use?
If you are wanting the extra power - use "premium" fuel - if you are saving money? Use "regular" fuel.
As long as it doesn't "ping" all is well, as far as generally accepted......
Is there a difference in standard street pump premiums?
Yes. ~1%-2% power output. Try a few and use the brand that works best in your bike. Or, you can bring your bike in and I can charge you a lot of money to test fuels for you.
Is there a difference in additive packages between different brands of fuel - even if they have the same "octane" rating?
Yep! There actually is. Some of the detergent packages are patented. I know for a fact that Chevron's Techron (techroline?) was patented. Years ago, when they first released it, they really loaded up the fuel with it. If your 4 stroke motorcycle jetting was too rich - it would actually, as an "oily solvent" with a flashpoint of ~1500f, build up on the insulator of the spark plug, unless you cleared it out every once in a while - it would actually foul!
That was many years ago and all is well now!
Oh - it really would remove minor fuel injector deposits, too!
Energy content?
There is a really SMALL difference in different pump premiums - depending on the fuel recipe - I'd suspect a insignificant difference - like .01% power difference. Relative importance between different standard fuels? Much less than being off by 1/4 main jet.
Octane boosters?
If they prevent "knock" in you vehicle, they WILL help produce more power, but if the engine is NOT knocking? No significant / cost effective, happy results. "Not a "buy" at this time." There ARE compounds that will improve power, yes, but they weren't down at Pep Boys and Grand Auto when we bought all of them in 1999.
If you make a compound that works, we are available to do confidential testing. (As far as testing, I dearly wish that there was an available, cost effective fuel compound that did work!)
Is there a difference in 100-105 octane race fuels as compared to street pump premium when used in a motorcycle engine?
Yes. Some of the best WILL ADD, without a doubt, repeatably, no question about it, 3%-4% power improvement (under 2.6% oxygen content and without nitrobenzene or related compounds). Some of the 100-105 octane race fuels that were not designed for high revving, low compression engines don't work very well at all - making roughly the same power as pump premium.
Have a doubt? Get some Nutec or Elf race fuel. You will feel it.
And yes, there are some odd compounds in race fuels. One of the above fuels left a brown carb deposit. Wouldn't wash out with gasoline, solvent, carb cleaner, 409, Simple Green, Fantastic or soap and water. Weird. Weirdest - it did dissolve and drip away in liquid form after being doused with an aerosol can of "Off" mosquito repellant that we had left over from the Brainard AMA National. It was a waxy deposit.
As far as what GJ and KC write, I've grew up reading and rereading everything that they both wrote. I ported an SR500 cylinder head just like GJ did in a magazine project. As I was doing it, I just knew I could spend more time and be more careful and end up with a small port that flowed more than his did. But, that's another "experience" (experience is what you get when you don't get what you want.) Actually, it did work OK. Ask some day.
I just wish they would tell you what did work, rather that explaining why something they didn't actually test themselves (like octane rating) doesn't work. It gets perpetuated throughout the industry - causing some nut (me) to spend hours explaining how things work today!!
Its long but informative.....and there's a few factors that are important besides octane.
There IS a difference in fuels - aside from the octane rating.
Different fuel blends burn at different rates under the same temperatures and pressures. Absolute fact.
Peak cylinder pressure, for best power output, MUST be timed to occur just after the top of the stroke.
To tune for maximum power, you would like to use a fuel that burns at the quickest possible rate - without "knock" (there - that covers pre-ignition and detonation) so you can initiate burning at the latest possible time and still produce peak cylinder pressure at around TDC. That way, the rising cylinder pressure pushes back down on the top of the rising piston for the shortest period of time - decreasing power lost there.
A more specific location for peak cylinder pressure would be ~15 degrees after TDC. There is some variance from that figure - but not more than a degree or so in an engine using gasoline. When the ignition timing is correct, power output will be highest for that rpm and throttle position.
(thanks, Al Cline!)
Octane?
If you look at the octane rating as only an indicator of what the fuel was designed for, you'd guess that a 120 octane fuel was probably designed for an engine that was prone to "knock" - like an older American V8 with relatively poor cooling and high compression. That fuel will be blended to burn at controllable rate that matches the high pressures and temperatures present AND resist "knock". A good match for those V8 engine conditions.
Burn Rates- That's the ticket!!
If you take that same fuel that worked well in the above V8, and run it in an engine, like a cbr900, with it's lower cranking compression and lower combustion chamber temps, it will, without a doubt, burn much too slowly at those lower temps and pressures and reach maximum cylinder pressure too far after TDC for best power.
Things generally burn slower when they are cooler and vice versa. Peak cylinder pressure will occur much past TDC - decreasing the power produced if you keep the same ignition timing.
You can advance ignition timing to try to recover power, but that will cause the air/fuel mixture to burn earlier in the crank stroke and spend, percentage wise, more of the energy produced by the expanding, burning mixture, pushing back down, trying to prevent the piston from rising up to the power stroke - robbing power.
If you MUST use a slow burning fuel, which USUALLY has a high octane rating, advancing the ignition timing will lessen the power loss, but the best results are usually obtained with the quickest burning fuel obtainable, that, of course, doesn't "knock".
All other factors being the same, except for burn rate - use the quickest burning fuel that doesn't "knock", light the spark in the middle of the combustion chamber, adjust ignition timing to reach peak cylinder pressure ~TDC and keep your mixture correct. When the ignition timing is correct, the engine will make best power for that fuel.
There is a difference in the burn rates of different brands of fuels that are available. Some compliment one engine and some compliment the existing tuning of a different type of engine. Our Supersport YZF750 was really responsive to different pump fuels and liked a different type of race fuel (same brand of fuel) than our gsxr750 Supersport bike. Something on the order of 1%-2% power difference.
Generally, the cbr900's are extremely power sensitive to different fuels. It has to do with the basic combustion design.
Does using a fuel with higher octane numbers automatically make more power?
Not unless they are preventing "knock".
My vehicle runs fine and doesn't "ping" on "regular" fuel, but, it's a little "peppier" with "premium" fuel. What should I use?
If you are wanting the extra power - use "premium" fuel - if you are saving money? Use "regular" fuel.
As long as it doesn't "ping" all is well, as far as generally accepted......
Is there a difference in standard street pump premiums?
Yes. ~1%-2% power output. Try a few and use the brand that works best in your bike. Or, you can bring your bike in and I can charge you a lot of money to test fuels for you.
Is there a difference in additive packages between different brands of fuel - even if they have the same "octane" rating?
Yep! There actually is. Some of the detergent packages are patented. I know for a fact that Chevron's Techron (techroline?) was patented. Years ago, when they first released it, they really loaded up the fuel with it. If your 4 stroke motorcycle jetting was too rich - it would actually, as an "oily solvent" with a flashpoint of ~1500f, build up on the insulator of the spark plug, unless you cleared it out every once in a while - it would actually foul!
That was many years ago and all is well now!
Oh - it really would remove minor fuel injector deposits, too!
Energy content?
There is a really SMALL difference in different pump premiums - depending on the fuel recipe - I'd suspect a insignificant difference - like .01% power difference. Relative importance between different standard fuels? Much less than being off by 1/4 main jet.
Octane boosters?
If they prevent "knock" in you vehicle, they WILL help produce more power, but if the engine is NOT knocking? No significant / cost effective, happy results. "Not a "buy" at this time." There ARE compounds that will improve power, yes, but they weren't down at Pep Boys and Grand Auto when we bought all of them in 1999.
If you make a compound that works, we are available to do confidential testing. (As far as testing, I dearly wish that there was an available, cost effective fuel compound that did work!)
Is there a difference in 100-105 octane race fuels as compared to street pump premium when used in a motorcycle engine?
Yes. Some of the best WILL ADD, without a doubt, repeatably, no question about it, 3%-4% power improvement (under 2.6% oxygen content and without nitrobenzene or related compounds). Some of the 100-105 octane race fuels that were not designed for high revving, low compression engines don't work very well at all - making roughly the same power as pump premium.
Have a doubt? Get some Nutec or Elf race fuel. You will feel it.
And yes, there are some odd compounds in race fuels. One of the above fuels left a brown carb deposit. Wouldn't wash out with gasoline, solvent, carb cleaner, 409, Simple Green, Fantastic or soap and water. Weird. Weirdest - it did dissolve and drip away in liquid form after being doused with an aerosol can of "Off" mosquito repellant that we had left over from the Brainard AMA National. It was a waxy deposit.
As far as what GJ and KC write, I've grew up reading and rereading everything that they both wrote. I ported an SR500 cylinder head just like GJ did in a magazine project. As I was doing it, I just knew I could spend more time and be more careful and end up with a small port that flowed more than his did. But, that's another "experience" (experience is what you get when you don't get what you want.) Actually, it did work OK. Ask some day.
I just wish they would tell you what did work, rather that explaining why something they didn't actually test themselves (like octane rating) doesn't work. It gets perpetuated throughout the industry - causing some nut (me) to spend hours explaining how things work today!!
That is the main point if ift works for you...
No the ECM does not adapt to the fuel octane. If it did Octane would no longer be usable.Hmmmm I wonder about consistency. I typically run 93 but after reading some of the gas reviews i loaded up with 87. Bought it home and changed the oil and plugs. Fire it up and here the tick tick tick ping ping ping. And I wonder if the one of the plugs is misfiring....now I'm thinking it may be the gas.
Is it possible that whatever you start using 93 or 87 your engine,ECM, fuel system adapts to it and any change causes a burn problem/ECM problem/Fuel Injection problem/
I know with cars whatever you have in it when you tune it, is what it runs best with.
Stop buying gas from the crack-town cum-n-go and get some 76 or Chevron gas. Unless you upped the compression, you should not be getting pinging....
Sorry dude, 93 octane is not cleaner, just burns SLOWER!
Absolutely, and the higher the octane, the higher the carbon buildup! That is why I run 87 or mid-grade, not the 91+ in my N/A busa, in the turbo, I always run 91+ for obvious reasons.mike it is very possible that you need to run some Redline injector cleaner.
with 10k on the clock it is very possible you have carbon build up putting 93 in is only a bandaid that could be hiding a more serious problem.
Try two tanks with the Redline in and then go back to 87.
Remember most times you cannot hear a Busa Detonate that takes out rods bigtime, putting 93 in you may not hear it but it still might be happening carbon suxs
HIGH-COMPRESSION or poser points, one of the other!
I say Yes and YES. If you are running too high of octane, would will carbon up things much quicker.
†Wç†ëD
Registered
no doubt lower octane will make the hayabusa run more efficiently, if its knocking you have bunk fuel. read the owners manual or the warning sticker on the tank, "this motorcycle is desinged to run on 87 octane" most likely cuz of the compression ratio. now the sticker on my 03 silver bullet says 92 octane, I know the compression on the gix is higher than the busa, makes sense to me?
†Wç†ëD
Registered
one more thing mikey, AMOCO should have been your first clue!
Just remember gentleman...The Manual does NOT say use 87 octane...It says AT LEAST 87 octane...
Also remember that we live in a variety of environments. We ride in different temperatures, humidity levels, and altitudes. Fuels are going to react differently for us based on these external factors.
As for saving money?
If this is where you gotta save it, sell the bike and take care of your other priorities...
This argument is going to get about as far as the Synthetic/Organic oil question... Use what works best for you.
Also remember that we live in a variety of environments. We ride in different temperatures, humidity levels, and altitudes. Fuels are going to react differently for us based on these external factors.
As for saving money?
This argument is going to get about as far as the Synthetic/Organic oil question... Use what works best for you.
Absolutely... the question here is "what is the good stuff"...
supernova1987a
Registered
That is also what I heard --- higher octane gas speeds up carbon buildup.Absolutely, and the higher the octane, the higher the carbon buildup! That is why I run 87 or mid-grade, not the 91+ in my N/A busa, in the turbo, I always run 91+ for obvious reasons.mike it is very possible that you need to run some Redline injector cleaner.
with 10k on the clock it is very possible you have carbon build up putting 93 in is only a bandaid that could be hiding a more serious problem.
Try two tanks with the Redline in and then go back to 87.
Remember most times you cannot hear a Busa Detonate that takes out rods bigtime, putting 93 in you may not hear it but it still might be happening carbon suxs
hayaboosta
Registered
The reason for the "carbon build up" with higher octane fuels is very simple.
If you are running a fuel with a octane rating HIGHER THAN NEEDED to prevent detonation and pinging, you are not burning all the fuel introduced into the combustion chamber.
The higher the octane, the slower the fuel burns. If the higher level of octane is not needed for your application, the amount of fuel introduced into the chamber will not have sufficient time to burn completely. Some of the unburnt fuel will remain and build up in the chamber on the piston dome, valves and seats.
This, I must say it is rarely a problem with any of the octane amounts available from a retail service stations, i.e. 87-93 octane.
If you are running a fuel with a octane rating HIGHER THAN NEEDED to prevent detonation and pinging, you are not burning all the fuel introduced into the combustion chamber.
The higher the octane, the slower the fuel burns. If the higher level of octane is not needed for your application, the amount of fuel introduced into the chamber will not have sufficient time to burn completely. Some of the unburnt fuel will remain and build up in the chamber on the piston dome, valves and seats.
This, I must say it is rarely a problem with any of the octane amounts available from a retail service stations, i.e. 87-93 octane.
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