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In europe, there are two types of unleaded fuel:
The 95 (octan, 85) and the 98 (also called in several countries "super+", octan 88).
Is it the same deal in US? What do you put in your bikes?


Modified by El Gladiateur at 10:24 PM 8/20/2005


Modified by El Gladiateur at 10:25 PM 8/20/2005


Modified by El Gladiateur at 1:18 AM 8/23/2005
 
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Re: Unleaded fuel or Super unleaded fuel? (El Gladiateur)

Here in Germany some stations also have a Super plus which is over 100 octane
 
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We have 3 levels of gas here in the U.S.: 91, 89 and 87. We compute the octane level with a different mathematical equation, hence, the different readings. I presume our "Super", which is 91 octane, is very similar to the European 88 octane. Most of us who ride streets will use the Super grade in order to protect against "pinging" or "knocking" which will damage our motors. All of our fuels are unleaded. Anyone who puts "regular" unleaded into his tank here is either an idiot or a squid (or both). For the track, many track day guys and racers will use a brand of fuel called VP Fuels, which is a specialty fuel company that mixes race fuel for all kinds of motorsports. Most people do just fine with the super unleaded in their bikes. Some of our stations do have high octane fuel (103 or more), but it's very expensive for everyday use, and frankly, I haven't seen that much benefit from it.
 
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Re: (wooleeboolee)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by wooleeboolee »</TD></TR><TR><TD CLASS="quote">We have 3 levels of gas here in the U.S.: 91, 89 and 87.</TD></TR></TABLE> We have many more "levels" of gas than this. In TX it is most common to see the pump have 87, 89 and 93. The more 93 octane fuel is removed from a set amount of oil the less 87 can be removed. So if you need lots of fuel it makes sense to produce it all at a lower level... thus 91 instead of 93. I think 91 is the norm in CA and the East Coast.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by wooleeboolee »</TD></TR><TR><TD CLASS="quote"> We compute the octane level with a different mathematical equation, hence, the different readings. </TD></TR></TABLE> We use the R+M/2 method where you average RON and MON:
"Octane rating number is defined as a value used to indicate the resistance of a motor fuel to knock. Octane numbers are based on a scale on which isooctane is 100 (minimal knock) and heptane is 0 (bad knock). A gasoline with an octane number of 92 has the same knock as a mixture of 92% isooctane and 8% heptane."

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by wooleeboolee »</TD></TR><TR><TD CLASS="quote">Most of us who ride streets will use the Super grade in order to protect against "pinging" or "knocking" which will damage our motors. All of our fuels are unleaded. Anyone who puts "regular" unleaded into his tank here is either an idiot or a squid (or both). </TD></TR></TABLE> THis is a very uneducated point of view, perpetuated by people, such as yourself, distributing their opinion as if it were fact. The higher the octane rating of a fuel the slower it will burn, the slower it burns the less usable power it develops. High octane fuel is very beneficial to high compression engines that need the higher octane to prevent premature detonation, but they make up for the higher octane rating by running a much higher compression ratio. In an aircooled motor it is possible to experience a knock (detonation caused by temperature and pressure - like a diesel engine) when the ambient temperature is high. However, your engine will produce the MOST power when running the LOWEST OCTANE possible that does NOT result in a knock. When you say you need to run high octane fuel all of the time you are being a chemistry squid. you may know lots about riding technique, but a few days in chem book would help, too. Oh, yeah,
it says to use the lowest possible. Check with your dealer, too, they'll recommend the lowest octane rating without knocking, too. Ask Jason, or Bill, they are well respected around here and will back this up.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by wooleeboolee »</TD></TR><TR><TD CLASS="quote">use the Super grade in order to protect against "pinging" or "knocking" which will damage our motors. </TD></TR></TABLE> Pinging and knocking are different, one is detonation caused by temperature resulting in part from the ambient temp, and then the temperature increase due to compression. Pinging is ignition of the fuel air mixture caused by an ignition source other than the spark plug. Pinging usually happens in engines that are running hot, regardless of ambient temp. Pinging is an after effect of low octane gas in a motor that is knocking, or has high carbon deposits.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by wooleeboolee »</TD></TR><TR><TD CLASS="quote"> Some of our stations do have high octane fuel (103 or more), but it's very expensive for everyday use, and frankly, I haven't seen that much benefit from it.</TD></TR></TABLE> Do you know why? Because your engine doesn't have a 13:1 compression ratio and it's not 140 degrees outside...

I hope this sparks some interest in actually researching this information. I'd love to see people go out an research this and come back to discuss it more.
 
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Discussion Starter #5
In france and generaly in europe, the "eurosuper" 95 has in fact a 95 RON and a 85 MON: that gives, in US, 90.
Following the same way, the french 98 is in US: (98+88)/2=93
 
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Re: (El Gladiateur)

This subject comes up on a monthly basis. The informed concensus is that most of us use US 87 RON with no ill effects. Do a search and you will learn more about the subject then you care to.
Fran
 
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Re: (wooleeboolee)

I guess the guys at BCM are idiots. They recommend 87 pump gas. I made 100 hp at the rear wheel on 87 pump gas with an 04 749 (Strati mod. pipe and BCM tuning). I thought that was decent. I guess I'm an idiot also.
 
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Re: (RI749)

Well, it's nice to have someone here who knows about fuel - welcome planejob, I was just going to write an answer for this, but you did it better than I ever could have.
 
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Re: (planejob)

91 is super in California, we have 93 and 94 (Sunoco only) here on the east coast.
 
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Discussion Starter #10
Re: (MikeB)

87,89,93 in FL. Mine runs the best off of 89 I've noticed.
 
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Re: (superduc21)

FWIW I've always run 87 in my 748 and never had any problems.


And I don't run it because its cheap, but because it runs fine on it and doesn't leave any residues that you can get with a high octane fuel on the wrong application.
 
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Re: (planejob)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by planejob »</TD></TR><TR><TD CLASS="quote"> THis is a very uneducated point of view, perpetuated by people, such as yourself, distributing their opinion as if it were fact. The higher the octane rating of a fuel the slower it will burn, the slower it burns the less usable power it develops. High octane fuel is very beneficial to high compression engines that need the higher octane to prevent premature detonation, but they make up for the higher octane rating by running a much higher compression ratio. </TD></TR></TABLE>

Lighten up, Francis. You are perpetuating one of the grand engine myths of all time with the slower burn theory. Higher octane gas does NOT control detonation by burning slower! In fact, a mixture that burns slower will make detonation WORSE, not better. Read up on detonation in an engine theory text and it will explain it. I have seen the "burn slower" argument written up in magazines so many times it's easy to see why it's accepted as fact, but it makes no sense if you look at what's going on.

Modern engines use higher compression ratios than classic engines, yet their ignition timing is retarded compared to classic engines. As in, even with higher compression they burn the mixture faster than old engines. How can this be if high compression requires a slower burning gasoline?

If burning the mixture quickly was a negative, MSD, dual plugs, and swirl in the intake charge would all be bad things. When was the last time you heard of a head design that sought to make the flow laminar so the flame wouldn't tumble/swirl/move around in the combustion chamber? Why do they want the charge to swirl??? To expose the flame to more unburned mixture in less amount of time? As in, burn the mixture faster. Fact is they can't do much about the flame front speed of pump gas no matter what the octane, so to speed up the burn they effectively bring the mixture to the flame instead.

There is no such thing as premature detonation. "Premature" implies it's expected to happen, but it happend too soon. Detonation is unwanted no matter when it occurs. (Ok, so VW did publish some info many years back that showed light knock could increase power. I've yet to see anyone who can manage knock well enough to exploit this...)

In a nutshell, at a given high temp and pressure, the mixture will auto-ignite, or detonate, in a finite amount of time, called a delay period. The trick is to burn the entire mixture before this delay period expires. Introducing a gas that burns slower into this equation will not bring the desired results... You want to either lengthen the delay (which is what higher octane gas does) or SPEED UP the burn, which is what a number of designs/mods do. Swirling the intake is desirable. Dual plugs are often desirable. Multiple sparks can be desirable. Getting the mixture burned quickly, before it can explode, is a good thing.

It wasn't stated, but the thought that slower burning gas is a good thing would imply that the mixture burning too fast is a problem. Detonation/knock is not caused by the flame front moving too quickly. Detonation happens when the mixture explodes. BOOM. All at once. Independant of any flame front. Many engine texts have photos of normal combustion vs detonation. The difference is quite apparent. Also, look at an indicater diagram of the pressure in the cylinder during normal combustion and detonation. Normal combustion raises the pressure in the cylinder (smooth curve on the diagram). Detonation creates a shock wave in the cylinder (spikes on the diagram), which bounces around and causes the "knock" you hear. And beats the hell out of the piston, along with destroying some of the boundry layer mojo going on so the mechanism that provides thermal protection is destroyed and things get hot, weaker, etc etc...

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by planejob »</TD></TR><TR><TD CLASS="quote">Pinging and knocking are different, one is detonation caused by temperature resulting in part from the ambient temp, and then the temperature increase due to compression. Pinging is ignition of the fuel air mixture caused by an ignition source other than the spark plug. Pinging usually happens in engines that are running hot, regardless of ambient temp. Pinging is an after effect of low octane gas in a motor that is knocking, or has high carbon deposits.
</TD></TR></TABLE>

This all depends on how you define pinging. That's one of the problems with any discusion on detonation/knock/auto-igniton/whatever you call it - everyone seems to have a little different version of what different terms mean. I've typically seen pinging used to describe mild knock. Detonation is made by worse by a higher temp and/or pressure. While compression does raise temp, the effect of the higher pressure is also a major player. Even if you kept the temp the same, rasing the pressure would increase the tendancy to knock. Anyway, what you refer to as pinging is typically described as pre-ignition in most tech literature I've seen.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by planejob »</TD></TR><TR><TD CLASS="quote"> I hope this sparks some interest in actually researching this information. </TD></TR></TABLE>
I'd be happy to discuss this further but the fact is most people get bored as hell by it or are so married to their opinion that it's a worthless discussion. If you want to prove your "burns slower" theory to me, start with providing a reference to an engineering publication that supports it. I will happily supply references to my claims if you'd like. (I'd do it now but most of my texts are at work - I'm sure i'd get the names wrong if I did them by memory) Or at least explain the whole dual plug/MSD/Intake swirl/ignition trends conflict. Yeah, I know dual plugs are often used with domed pistons to provide a "more complete" burn. But they are also used on large bore cylinders with flat top pistons, and there is no denying they introduce a second flame front which has to mean the mixture burns faster.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by planejob »</TD></TR><TR><TD CLASS="quote"> A gasoline with an octane number of 92 has the same knock as a mixture of 92% isooctane and 8% heptane." </TD></TR></TABLE>

So what ratio does gasoline with an octane of 102 compare to?
 
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Re: (DesmoDog)

I remember seeing 86 octane in Durango, CO...ifn I remember correctly it has something to do with the altitude. My bike runs great on 87 in Pgh. FYI
 
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Re: (DesmoDog)

I went back, looked it up, and at this time I would like to stand by my original statement regarding fuel. I like what you have to say, and am looking into it, but I'll not just agree with you. I might change my mind, but I'm not ready to discard a bunch of info right now.

Oh, and you 102 octane, it's like a 2% better than isooctane. isooctane and heptane are just the chemicals used to define the scale, you are burnging gasoline that 'performs like a mixture of' isooctane and heptane. So if you are doing 102 octane, then you have the anti-knock properties of a fuel that performs 2% better than isooctane.
 
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Re: (planejob)

and a little more, courtesy of the FTC (because our government is reputable
):
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote »</TD></TR><TR><TD CLASS="quote">The Low-Down on High Octane Gasoline
Are you tempted to buy a high octane gasoline for your car because you want to improve its performance? If so, take note: the recommended gasoline for most cars is regular octane. In fact, in most cases, using a higher octane gasoline than your owner's manual recommends offers absolutely no benefit. It won't make your car perform better, go faster, get better mileage or run cleaner. Your best bet: listen to your owner's manual.

The only time you might need to switch to a higher octane level is if your car engine knocks when you use the recommended fuel. This happens to a small percentage of cars.

Unless your engine is knocking, buying higher octane gasoline is a waste of money, too. Premium gas costs 15 to 20 cents per gallon more than regular. That can add up to $100 or more a year in extra costs. Studies indicate that altogether, drivers may be spending hundreds of millions of dollars each year for higher octane gas than they need.

What are octane ratings?
Octane ratings measure a gasoline's ability to resist engine knock, a rattling or pinging sound that results from premature ignition of the compressed fuel-air mixture in one or more cylinders. Most gas stations offer three octane grades: regular (usually 87 octane), mid-grade (usually 89 octane) and premium (usually 92 or 93). The ratings must be posted on bright yellow stickers on each gasoline pump.

What's the right octane level for your car?
Check your owner's manual to determine the right octane level for your car. Regular octane is recommended for most cars. However, some cars with high compression engines, like sports cars and certain luxury cars, need mid-grade or premium gasoline to prevent knock.

How can you tell if you're using the right octane level? Listen to your car's engine. If it doesn't knock when you use the recommended octane, you're using the right grade of gasoline.

Will higher octane gasoline clean your engine better?
As a rule, high octane gasoline does not outperform regular octane in preventing engine deposits from forming, in removing them, or in cleaning your car's engine. In fact, the U.S. Environmental Protection Agency requires that all octane grades of all brands of gasoline contain engine cleaning detergent additives to protect against the build-up of harmful levels of engine deposits during the expected life of your car.

Should you ever switch to a higher octane gasoline?
A few car engines may knock or ping - even if you use the recommended octane. If this happens, try switching to the next highest octane grade. In many cases, switching to the mid-grade or premium-grade gasoline will eliminate the knock. If the knocking or pinging continues after one or two fill-ups, you may need a tune-up or some other repair. After that work is done, go back to the lowest octane grade at which your engine runs without knocking.

Is knocking harmful?
Occasional light knocking or pinging won't harm your engine, and doesn't indicate a need for higher octane. But don't ignore severe knocking. A heavy or persistent knock can lead to engine damage.

Is all "premium" or "regular" gasoline the same?
The octane rating of gasoline marked "premium" or "regular" is not consistent across the country. One state may require a minimum octane rating of 92 for all premium gasoline, while another may allow 90 octane to be called premium. To make sure you know what you're buying, check the octane rating on the yellow sticker on the gas pump instead of relying on the name "premium" or "regular."

For More Information
If you're concerned about the accuracy of an octane label - or if you don't see a yellow octane sticker on a gasoline pump, write: Consumer Response Center, Federal Trade Commission, Washington, DC 20580.

The FTC works for the consumer to prevent fraudulent, deceptive and unfair business practices in the marketplace and to provide information to help consumers spot, stop and avoid them. To file a complaint or to get free information on consumer issues, visit http://www.ftc.gov or call toll-free, 1-877-FTC-HELP (1-877-382-4357); TTY: 1-866-653-4261. The FTC enters Internet, telemarketing, identity theft and other fraud-related complaints into Consumer Sentinel, a secure, online database available to hundreds of civil and criminal law enforcement agencies in the U.S. and abroad.

October 2003
</TD></TR></TABLE>
 
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Re: (planejob)

http://media.corrado-club.ca/tech/detonation.pdf
http://www.jcmmachine.com/deto...n.htm

I believe the issue with burn speed is that you want the gas/air mixture to burn rapidly before it can detonate. A normal burn wave can "spark" detonation, as can pre-ignition (prior to the spark plug firing) - the bad thing is the detonation wave, a very rapid spike in pressure causing shock waves that bounce around and destroy metal. I'm not sure what the microscopic difference is - gas and air are undergoing energy-liberating reactions in both cases, so the difference must be in the way the wave front interacts with the unburned mixture? - but I'd be curious if someone has a link to a technical article that explains this.
 
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Re: (JeffKoch)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JeffKoch »</TD></TR><TR><TD CLASS="quote"> - but I'd be curious if someone has a link to a technical article that explains this.
</TD></TR></TABLE>

See if this works... Seems like it's all about the 'boundry layer'. Once that's gone, it's curtains.


http://www.motorcycle.com/mo/mcrob/rt-fuel2.html
 
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Re: (planejob)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by planejob »</TD></TR><TR><TD CLASS="quote">The higher the octane rating of a fuel the slower it will burn, the slower it burns the less usable power it develops.</TD></TR></TABLE>

Uh, no, the higher the octane the more stable the fuel is. All gasoline, regardless of octane rating (hydrocarbon content) burns at exactly the same rate. The primary difference between pump octane grades are the additives and the amount of aromatic hydrocarbons contained in the fuel. This is why California only gets 91-- the enviro-nutjobs running the place have ridiculously strict emissions requirements, which is why Cali gas is 10% ethanol and has every additive including the kitchen sink mixed into it.

Changing the octane of gasoline is simple: Just add an aromatic hydrocarbon such as Toluene or Xylene (and some ATF oil) in the proper proportions, and it's not difficult to raise 94 octane pump gas into the 100+ octane range.

Whether you call detonation ping, knock, or whatever else, it's still detonation, and it's still referred to as "preignition" as something (excessive heat, or hot spots in the combustion chambers) is lighting off the charge before the plug does. Using a higher octane, and thus more stable fuel, prevents this from happening.

All of the guys who run very high boost on turbocharged cars (e.g. me) are all too familiar with detonation and the stability of gas at a given temperature and pressure.

In the context of our Ducs, most bikes run in the 11:0 to 12:0 compression range. This is very high compression, and in hot climates (or when flogging the hell out of it), there is benefit to running higher octane fuel. Just because you can't hear detonation doesn't mean it isn't happening at some level.

In engines that dynamically retard ignition timing based on air charge temperature and duty cycle, running a higher octane fuel will typically result in a good deal more performance, as the computer will not pull timing (as much) to prevent detonation, when running higher octane fuel.

I run 94 in my bike on the road, as that's what tends to keep it most happy when thudding around in NY traffic.


We won't talk about the VP C10 (104 octane) I have to run in my Supra to keep it from going boom.

Stupid fast/shiney thing hobby.
 
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Re: (900CR)

Ah, perfect.
Makes sense now, so the essential issue is when you have a shock wave that is itself strong enough to ignite the unburned fuel, in front of the basically diffusive flame front. High initial pressures (high compression) will make this more likely, as can fuel composition (octane) and cylinder and piston design. Destroying the boundary layer is another bad effect, allowing very high-temperature gas to come into direct contact with the metal surfaces.
 
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Re: (Simba)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Simba »</TD></TR><TR><TD CLASS="quote">Whether you call detonation ping, knock, or whatever else, it's still detonation, and it's still referred to as "preignition" as something (excessive heat, or hot spots in the combustion chambers) is lighting off the charge before the plug does. </TD></TR></TABLE>

I agree with everything except for this. Preignition can cause detonation (just the same as advance timing does), but they are two distinctly different phenomenon (phenomenons? Phenomenoses? Phenomenie?). Detonation can and does occur without preignition. I think it's CF Taylor's book (Fundamentals of IC Engines?) that has the pictures of this - it clearly occurs after normal combustion has started.
 
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