Octane, Money and You??? What do you run in your 250 and why?

[Driddle]

Originally Posted by BlueRaven

No need to drain fuel there just more octane in one. Oil is different.

So the next time I fill up I can just put 87 on top of the 91?

[BlueRaven]

yup

[ChaoSS]

Originally Posted by BlueRaven

I was told by my mechanic that is no problem to use 87 if you ride your bike on a regular basis but to put 91 if the bike is gonna be sitting for extended length of time. Makes sense cause 87 has ethanol or corn crap as i call it at the majority of the gas stations in Canada. I only use 91 in all of my vehicles.

Hmmm. I don't know about other states, or Canada, but around here all gas has corn crap in it, and the new E15 they are rolling out in places is usually just the higher octane 91 gas.

[Jiggles]

87. Why would you degrade your performance with 91? Unless the 91 is no ethanol and the 87 is ethanol, then don't use 91

[Brother Michigan]

The whole "premium doesn't have ethanol in it" thing is bunk. Ethanol is higher octane than even premium gasoline, so adding ethanol would raise the octane, not lower it.

[beazy411]

If you're looking for ethanol free gas, go to http://pure-gas.org/ . I am lucky to have a "pure gas" station about 1 mile from where I live and it's on the correct side of the road on the way home so my truck and bike both get fueled up there. It is about 15-20 cents more a gallon but in the truck at least the improvement in fuel mileage is worth it. On a 4.5gal tank, who cares?

[Daks]

You're imagining it. Had you not noticed you hit the 87, you would have not noticed a loss in "peppy-ness".

Manual recommends 87. Use 87 and stop wasting money.

[ChaoSS]

Originally Posted by Brother Michigan

The whole "premium doesn't have ethanol in it" thing is bunk. Ethanol is higher octane than even premium gasoline, so adding ethanol would raise the octane, not lower it.

Well, there are other things that can be used to raise the octane, so it is entirely possible to have the low octane stuff have corn gas and not the high octane stuff. I just don't know if other places do that, though I've heard that before.

Originally Posted by beazy411

If you're looking for ethanol free gas, go to http://pure-gas.org/ . I am lucky to have a "pure gas" station about 1 mile from where I live and it's on the correct side of the road on the way home so my truck and bike both get fueled up there. It is about 15-20 cents more a gallon but in the truck at least the improvement in fuel mileage is worth it. On a 4.5gal tank, who cares?

Would be nice if I could get real gas within a few hundred miles of me.

[Alex]

/merged

[corralhollowkid]

Originally Posted by Dano

i always use 87 why pay more for gas than you need to????

Point well made ... But its gonna take me about 6 tanks to save enuff for a beer

gotta love the ninja
Posted via Mobile Device

[Brother Michigan]

Originally Posted by ChaoSS

Well, there are other things that can be used to raise the octane, so it is entirely possible to have the low octane stuff have corn gas and not the high octane stuff. I just don't know if other places do that, though I've heard that before.

Good point, but I'm willing to bet ethanol is cheaper than other octane boosters that might end up in gas.

Originally Posted by ChaoSS

Would be nice if I could get real gas within a few hundred miles of me.

I've got the same problem here. I just need to strap some 5 gallon cans to the side of my bike and make a trip.

[ChaoSS]

Originally Posted by Brother Michigan

Good point, but I'm willing to bet ethanol is cheaper than other octane boosters that might end up in gas.



I've got the same problem here. I just need to strap some 5 gallon cans to the side of my bike and make a trip.

Check the "E10 plus water equals gasoline" or whatever thread.

[Kokosun]

Here in the UK, gas is either 95 (standard) or 98 (premium) octane - I use 95. I have a US bike (bought in Carrollton, TX) and it doesn't seem to mind the higher octane than was intended for it. In fact, I haven't noticed any ill effects.

[Alex]

Those octane numbers aren't on the same scale / measurement. Check out the early posts in this thread that go through the calculations of RON, MON, RON+MON/2, etc.

[JustRidin]

90+ octane. She takes so little to fill up anyhow I don't have any remorse on spending the extra dollar or less.

[Kokosun]

Originally Posted by Alex

Those octane numbers aren't on the same scale / measurement. Check out the early posts in this thread that go through the calculations of RON, MON, RON+MON/2, etc.

Ooops. Sorry. I thought that RON was the same everywhere. I didn't realise that there were geographic differences. I'll go cruise this thread and learn something new.

:-)

[Driddle]

Originally Posted by ChaoSS

Would be nice if I could get real gas within a few hundred miles of me.

California sucks sometimes
The South (for some reason) is a cluster **** of pure-gas stations.
Pretty much everywhere is.. except California.
Go us!!

Just switched over from 91 to 87 (the previous owner ran 91.. n00b)

[BIGREDIOWAN]

Well, I had been using 91 or premium.............apparently I don't need to do that so I'll switch to 87 next time I fill up. Maybe that's why my MPG is right at 50?

[n4mwd]

Originally Posted by corralhollowkid

Hello last time I was at the pump I was about completely out of fuel, and broke (as usual) so I dropped $2 worth of fuel in and accidentally hit the 87 button. Almost immediately I noticed my ninjette didn't seem quite as peppy as before.

Its just your imagination. Higher octane means that the gas burns slower to prevent knock in high compression engines. For our bikes, use 87, for supersports like the ZX-6 and up, use premium.

Originally Posted by Driddle

When I bought my bike (not too long ago) the guy was running 91 (n00b). I have only filled it up twice, but I've used 91 since cause I havent run dry.
Is there a way I can switch it to 87? I figured I cant just mix the two fuels.
Do i have to drain the carbs and what not?

It mixes just fine. In fact, that's what mid-grade is. Its a 50-50 mix made in the pump itself.

Originally Posted by Brother Michigan

The whole "premium doesn't have ethanol in it" thing is bunk. Ethanol is higher octane than even premium gasoline, so adding ethanol would raise the octane, not lower it.

Originally Posted by BIGREDIOWAN

Well, I had been using 91 or premium.............apparently I don't need to do that so I'll switch to 87 next time I fill up. Maybe that's why my MPG is right at 50?

Higher octane doesn't burn as fast so its going to give you less not more horsepower. As far as MPG, it depends on how you ride. But if the higher octane was achieved by adding more alcohol, then you have less BTU and a reduction in MPG that seems roughly equal to half the percentage of alcohol in the gas. So 10% alcohol reduces your MPG by about 5%.

[Alex]

This is a long thread, but that discussion has happened a few times in it already. Higher octane fuel doesn't necessarily burn slower than lower octane fuel. It might, but it varies depending on a number of other factors. The only foolproof quality that can be guaranteed by higher octane vs lower octane is its initial resistance to pre-ignition / detonation. The higher octane fuel can be run with higher effective compression ratios without igniting early and damaging the engine. That's why higher octane fuel is specified on motors that have higher effective compression. Engines with higher effective compression (and higher rev capabilities) have better performance than those with lower spec, which is why higher octane fuel is often specified for higher performance vehicles.

[Panda]

Originally Posted by n4mwd

Higher octane doesn't burn as fast so its going to give you less not more horsepower.

?? This doesn't sound right. What do you mean by "fast"? Higher octane fuel doesn't detonate as easily but the detonation rates should be similar if not for all practical intents and purpose the same.

[adouglas]

I think you're looking at it incorrectly, especially with the "less not more horsepower" bit.

To be more specific, higher-octane fuel is more resistant to detonation. That's not the same thing as "burning slower."

What does "resistant to detonation" mean? We all know that gas gets hot when you compress it. This is, of course, how diesels work. Big compression ratios, fuel designed to ignite more easily when compressed, there you go. Diesel doesn't carry an octane rating but if it did, it would be very very low.

Detonation is the fuel-air charge igniting before you want it to. It is a Bad Thing for the engine. It is also called "knock." So you want to avoid it. It has nothing to do with how fast the fuel-air mixture burns. It has everything to do with how easy it is to get the mixture to start burning in the first place.

The higher the compression ratio of the engine, the more the mixture will heat. Therefore high-compression engines (i.e. high-horsepower engines like you find in supersports) need high-octane gas to avoid detonation.

The BTU content of gasoline does not, I believe, decrease in higher octane fuels. Therefore you're not going to get less horsepower by running premium.

As has been said many, many times, putting higher octane gas in your engine than the manufacturer specifies doesn't do ANYTHING but lighten your wallet faster. The performance gains of having less money in your pocket have yet to be quantified.

[adouglas]

In writing the above post I realized that I have a belief that I cannot verify. Could someone check me on this?

I believe that detonation due to too-low octane fuel is more likely if the engine is under heavy load. I don't remember where I got this idea.

Is that right or not?

If it is, there's an important implication: It should in theory be okay to run a lower-grade fuel in your high-compression engine in an emergency, provided you take it easy while burning it.

[DaBlue1]

More Octane For More Power? | Mythbusters
From rotgut to race gas, we see how octane affects a stock streetbike on the dyno

From the August, 2011 issue of Super Streetbike
By Justin Fivella


When it comes to octane and power, people’s beliefs are all over the board. Whether you think less octane is better because it “burns faster” or follow the more is better theory, everybody has an opinion as to what the best swill for their sportbike might be.

While we’ve heard every hypothesis under the sun, we’ve also witnessed many a rider fill his bike with 100-octane race gas before a bike night or track day (we’ve even been guilty ourselves). Whether it actually did anything or not, we all swore it pulled harder…

All claims aside, modern sportbikes are marvels of technology, and despite sky-high compression ratios over 12:1, they perform at remarkable levels on cut-rate gas. We can thank ultra efficient combustion chambers, high-powered ignition systems and oh-so precise fuel injection units for this symphony of speed.

Aside from the techie singsong, we’ve read enough octane wars on forums across the Web to know it’s a hotly contested topic. To get the skinny on octane we decided to hit the dyno and see how octane affects horsepower. Here’s how it went down.

The test
Instead of writing a novel on octane and its effects on high-performance internal combustion motors we took a rather simple approach to our investigation. The basis of our test was to sample all octane levels of readily available pump gas and even some 117+ octane C16 on the dyno to see if the increased octane netted any power increases. Crazy oxygenated fuels were omitted from the test; instead the focus was placed on octane and its relation to power on a STOCK bike.

The test mule was a 2011 Suzuki GSX-R600 and the tank was drained dry between each change in octane. Along with the dyno results and the air-fuel ratio, we also monitored detonation with a rather simple tool—a stethoscope—which was placed on the motor. If detonation was heard, the pull was to be aborted.

To keep things fair we used 87, 89 and 91 octane fuel from Union 76 all purchased on the same day and at the same pump. The C16 was brought along as the wild card.

The data
All dyno runs were made within five minutes of each other and the bike was at normal operating temperature before any runs were attempted. Although unscientific in form, there wasn’t any measurable detonation throughout the entire test, not even on 87 octane. As for the AFRs, they were all within .2 of each other and in regards to the dyno numbers, the differences were no greater than .4 HP, which is well within the margin of error for a dyno. The 87 produced as much power as the 89, 91 and even the C16.

Deciphering the results
So what does this mean? That most modern stock sportbikes won’t necessarily make more power with higher octane fuel. However, if you’ve increased the compression with a built motor or are running forced induction and/or nitrous, then higher octane will allow for more ignition advance, higher boost and a bigger shot, thus producing more power.

But before the hate mail comes flooding in let’s get this straight, we’re not saying to automatically start using 87 octane in your motors. In fact, we advise you adhere to your owner’s manual recommendations since decreased octane leaves a smaller safety cushion against detonation. While your bike may run great on 87 octane under ideal conditions, get it on a hot day with less-than-stellar gas and you might run into some detonation–and that’s a bad thing.

While more octane does in fact net more resistance to detonation and thus a higher safety cushion, if your wallet is pinched and you live at partial throttle then maybe the extra dollar or so you’ll save is worth switching to the cheap stuff. But don’t go skimping on the inferior mix if the temperatures are up and you’re the type to pin it to win it.

Myth: Busted
Higher octane doesn’t necessarily mean more power on a stock bike. It will, however, give you a larger margin of error against detonation. Only you can be the judge as to what’s best for you, but if you choose to run the cheap stuff keep a keen ear out for the nasty clacking sound—detonation.

As for the race gas, unless the sweet aroma wafting from the tailpipe is worth the increased price of admission, save that liquid gold for the juiced-up bikes. Your mostly stocker will be just fine on the pump stuff.

Read more: http://www.superstreetbike.com/howto...#ixzz2Z7oCaVzC

[Alex]

Originally Posted by adouglas

I believe that detonation due to too-low octane fuel is more likely if the engine is under heavy load. I don't remember where I got this idea.

Is that right or not?

If it is, there's an important implication: It should in theory be okay to run a lower-grade fuel in your high-compression engine in an emergency, provided you take it easy while burning it.

Yes, that is correct. Under heavy load, the engine is running more fuel to maintain that power. More fuel makes detonation more likely. If you need to run lower octane fuel than recommended (stuck in the boonies and can't get premium for a vehicle that needs it), the right thing to do is to take it easy. Moderate revs, moderate throttle, and don't run it under any heavy loads.

[corralhollowkid]

This thread is AWESOME :+) thanks y'all for the education !

I'm gonna run 87 and never look back !!!

CHK
Posted via Mobile Device

[Jiggles]

Originally Posted by Brother Michigan

The whole "premium doesn't have ethanol in it" thing is bunk. Ethanol is higher octane than even premium gasoline, so adding ethanol would raise the octane, not lower it.

Actually a lot of stations have 91 that is no ethanol and 87 that is 10%. If you look at the pump it will tell you.

Originally Posted by JustRidin

90+ octane. She takes so little to fill up anyhow I don't have any remorse on spending the extra dollar or less.

There was a thread started on another forum that I linked somewhere on here. A guy dyno'd his ninja 1000 (which takes 87) with 87 and 91. The 91 test left him with 5hp less than the 87 run. That's about a 4% decrease, not very significant but, why pay more for less performance?

[DaBlue1]

This is another interesting article from Motorcycle Performance, America's Quickest Ducati

Bad Gasoline
Gasoline update 7/12/08

One of the most frequently encountered problems this season is the issue of “bad gas”. While not involving flatulence, it just as big a problem.

We have had more fuel-related problems ranging from poor starting, hesitation, etc. to just plain “quit and won’t restart” this year than in any of the past 25 years we have been here.

A further explanation of the three different areas of concern with gasoline may be in order for those who wish to pursue it.

1.) OCTANE

This is the resistance to detonation the gasoline offers. The most common grades of gasoline are: REGULAR at 87 Octane; MID-GRADE at 87-90 Octane; PREMIUM at generally 93 Octane. Other custom-built racing gasolines can offer up to 125 Octane. Octane is an indicator of the speed at which the gasoline burns in the engine.

The higher the octane, the slower the speed of the burn; the lower the octane the faster the burn. If the burn is too fast, uncontrolled combustion can occur. This most often is heard as “pinging” and is commonly referred to as detonation. This is because instead of burning through top dead center of the combustion stroke, the entire charge is ignited too early and explodes in the chamber and acts as a bomb. Conversely, if the speed of the burn is too slow, it continues after the useful work can be done in the motor and manifests itself as poor throttle response, reduced power output and increased emissions and fuel consumption. An engineering fact: THE MOST HORSEPOWER IS MADE AT THE THRESHOLD OF DETONATION. We have often gained horsepower on the dyno and felt improved starting and driveability going from Premium grade gas to Regular. This change was recently quantified in a customer’s Ducati M900 by reducing the cranking time to start-up from 15 to 3 revolutions, although part of the improvement is explained below.

The multi-valve combustion chambers and their reduced flame front propagation distances in the modern engines virtually eliminates the need for high-octane gasoline.

2.) COMBUSTIBILITY

This is the ability of the gas to burn. As mentioned above, gasoline needs to burn to be of any value in the motor. Modern gasoline has been subject to formulation restrictions that now make it able to sit only 4 to 6 weeks after manufacture before its usefulness as a fuel is compromised due to reduced combustibility. This is basically a separate issue from the speed of the burn as controlled by octane.

The biggest issue is the fact that the “volatiles” in this new formulation evaporate very quickly.

The reason these “volatiles” are so important is that they are the part of the gasoline that affects starting and throttle response. That is why you can often feel the difference between individual tanks of gas when it comes to starting, cold running and acceleration at lower rpms. The evaporation of these volatiles leaves a thicker, more viscous residue that becomes difficult for the carburetor to break up into combustible droplets. This sludge will adhere to the intake runner walls or goo its way into the combustion chamber.

This difference becomes more pronounced with carbureted bikes using a hemi-style engine design (Harleys, Viragos, BMW, Ducati, etc.) as opposed to 4-valve and/or fuel injected motors.

One of the recurring themes in these problems has been the use of Premium gasoline.

There are no 4-valves bikes made in the last 20 years that need premium gasoline for normal street use. Very few of the 2-valve bikes need it either. One of the problems with premium is the fact that it is not used as much and sits in underground tanks much longer than the other grades, with the attending evaporation of the volatiles present at manufacture. This coupled with the more efficient combustion chambers used today makes the problem even worse. A second issue is the different ways used to achieve that higher octane. Each company has a different formulation, and with the high horsepower to displacement ratios of the newer bikes, tuning for this can be an issue.

A good rule of thumb is if the bike doesn’t ping and runs acceptably with regular, DON’T use Premium. Regular is sold faster, is fresher and will generally start easier and have better throttle response than the higher octane gasolines. Not nearly as many cars use premium as they can compensate for the lower octane of regular with built-in detonation sensors to compensate for the octane, thus further reducing the amount of premium sold. Most underground tanks hold in excess of 4,000 gallons of gas, so with primarily motorcyclists buying it three or four gallons at a time, it will be there quite awhile. Also as the level in the tank drops it affords more opportunity for the volatiles to evaporate. It doesn’t matter what the owner’s manual or your friends say. We have often GAINED horsepower on the dyno when we took away octane.

We have had to make arrangements to properly dispose of all the gas that makes a bike run terribly, but works fine in a car or truck. So try a tankful or two of regular and see how the starting and performance changes. If the bike is unhappy, go back to what you were using before, but bear in mind the information here and be ready to switch if things change.

3.) ETHANOL

A component of gasoline that is seeing increased use is ethanol. A member of the alcohol family, it is produced by vegetable matter (not just corn). Ethanol has three physical characteristics that distinguish it.

First, it has 30% fewer BTUs (British Thermal Units) per pound than gasoline. This means that a gallon of ethanol produces less power in an undiluted comparison with a gallon of gasoline and a corresponding reduction in power as percentage of its addition to gasoline (eg: 10% ethanol produces 3% less power with the same jetting). The E85 blend (15% gasoline, 85% ethanol) produces documented losses of mileage of 30-36%.

Second, the detonation suppression characteristics of ethanol and its cousin methanol allow it to be used to raise the effective octane of gasoline it is added to. Gasoline blenders will use this to build the higher octane numbers of mid-grade and premium gasoline. Ethanol’s reduced cost per gallon makes this very attractive. E85 is generally $0.50-0.60 cheaper per gallon than even the 10% dosed gasoline.

Third is the affinity of ethanol for water. Gas line de-icer is made of either methanol or isopropyl alcohol, chemical relatives of ethanol. This means water in the air will be drawn into the fuel. This accelerates the fuel’s degradation and decreases combustibility as explained in section 2. While the exposure to air is reduced in fuel-injected applications, it still is a factor. Combined with the alkaline reactivity of ethanol, fuel system components can suffer.

One other aspect of the ethanol content is just that. When the pump says “may contain up to 10% ethanol,” it may legally contain up to 20% by law, allowing for “error.” At this point in history, the use of ethanol is primarily a politically driven issue. The logic of the use of ethanol in the current format is flawed.

a) It costs more to produce a gallon than it sells for.

b) It accelerates the deterioration of gasoline in storage, even with the use of a stabilizer.

c) It reduces the power and mileage in all conventional applications.

To allow the proper use of ethanol, compression ratios, cam timing, ignition timing, and jetting/fuel mapping need different configurations. While cams, ignition, and fuel can be adjusted on the fly, compression ratios are not easily or quickly changed. Having run alcohol-burning combinations for 25 years, this is an empirically determined fact.

One of the other less-publicized aspects of the ethanol debate is the fact that there is a $0.54 per gallon tariff on imported ethanol. Just ask your elected representative why this is. Politicians can’t regulate politics much less be trusted to properly regulate the economics and engineering aspects of normal lives. The ethanol debacle is continuing proof of that.

The final pinprick in the balloon of ethanol is the fact that last fall, we switched from BP gas with ethanol to Shell gasoline without ethanol and our gasoline problems have virtually disappeared, to our great delight.

So, if there is a choice – DO NOT USE ETHANOL-BLENDED GASOLINE! Only pure regular gasoline (read the pump carefully). A good way to avoid problems such as this is to be certain you buy gasoline at a name-brand station. The neighborhood convenience store buys gas from a broker, so you have no idea what it is. That gasoline is purchased by price, not specification

Remember- always buy brand name fuels, and avoid ethanol, to reduce the potential entertainment that accompanies poor quality gasoline.

© Bill Whisenant 2007
updated 10/23/07

[Panda]

Originally Posted by adouglas

The performance gains of having less money in your pocket have yet to be quantified.

I disagree! Less money in my wallet always makes me go slower!

[adouglas]

Originally Posted by Jiggles

There was a thread started on another forum that I linked somewhere on here. A guy dyno'd his ninja 1000 (which takes 87) with 87 and 91. The 91 test left him with 5hp less than the 87 run. That's about a 4% decrease, not very significant but, why pay more for less performance?

So we have an actual dyno chart from that magazine article that shows there's no real difference in horsepower, and some thread about this guy who said he dynoed his bike and claimed he saw a significant decrease in power.

Gotta love the Interwebz. Every possible point of view and interpretation of "fact" is out there. Pick the one that matches your own personal reality.

[Jiggles]

Originally Posted by adouglas

So we have an actual dyno chart from that magazine article that shows there's no real difference in horsepower, and some thread about this guy who said he dynoed his bike and claimed he saw a significant decrease in power.

Gotta love the Interwebz. Every possible point of view and interpretation of "fact" is out there. Pick the one that matches your own personal reality.

Well they were different bikes. A gixxer needing 91 and a ninja needing 87. I guess its entirely possible their results would be the same, and also possible they wouldn't be.

[LNasty]

FU**, I ahve been using 93 this whole time cause two seperate ****ing dealers service guys said I should be. Maybe they are used to dealing with people with bigger more advanced bikes than the 250, guess I am going back to 87 then. Chevron every fill up!

[LNasty]

Originally Posted by Driddle

California sucks sometimes
The South (for some reason) is a cluster **** of pure-gas stations.
Pretty much everywhere is.. except California.
Go us!!

Just switched over from 91 to 87 (the previous owner ran 91.. n00b)

LOL, thought it was bad here in TExas, can't find ethanol free anywhere, but **** me, Liberal a** Cali is definitly takes the cake. suprised they don't add some sort of carbon tax as well

[corralhollowkid]

No pure gas anywhere close to San Diego

I wonder if I could buy it in bulk, direcrtly from a local lubricants distributor ... I may call and find out.
Posted via Mobile Device

[Jiggles]

Originally Posted by corralhollowkid

No pure gas anywhere close to San Diego

I wonder if I could buy it in bulk, direcrtly from a local lubricants distributor ... I may call and find out.
Posted via Mobile Device

You can order no ethanol race gas. I think its only around $10/gallon

[corralhollowkid]

My lubricants dealer laughed when I called and asked, so I guess that's a big NO... LoL

Edit: not exactly no... The min order is 500 gallons, for 87/no ethanol

I'll keep lookin...

HEY... Don't give them thieves in SacTown any ideas or we'll be the first state to implement the carbon tax !!

[n4mwd]

Burns faster or slower:

In a gasoline engine, the spark happens just before the piston is at TDC - aka spark advance. This is because it takes gas a certain amount of time to burn. If the gas burns at the right speed, the piston reaches TDC before any significant force is generated and the total fuel charge ignites more thoroughly. BUT If the gas burns too fast, you have a situation where the piston is being forced downward before its time and actually tries to turn the crank the opposite way.

Advancing the spark gives the engine more HP and makes it run cleaner and more efficient. There is a formula somewhere that tells exactly how much of an advance is optimal and is based on octane, speed and vacuum. Vacuum is an indicator of power drawn from the engine. Modern bikes/cars all use spark advance.

But it really shouldn't be confused with compressive pre-detonation. That is where the gas charge ignites on its own without a spark. If the fuel is volatile enough to cause compressive pre-detonation, then the engine isn't going to run at all. The compression ratio wont change under load so it will ether run or it wont.

Its not the same as a diesel. A diesel doesn't even have a fuel charge when it compresses so there can never be compressive pre-detonation in a diesel. Diesel fuel does burn significantly slower than gasoline so if it had an octane rating, it would be way higher than 87.

Older cars would sometimes keep running after the engine was turned off. This was called "dieseling" because there was no spark and yet the engine was still running. On first thought, it might seem that the gas charge was igniting based on compression alone, but the fact is that it actually ignites because of hot carbon/lead buildups on the spark plugs. So therefore, a car would never "diesel" when it was cold.

Ethanol:

My motto -> "If 0.08% is too much for the rider, then it ought to be too much for the bike."

But then again, as much as I hate alcohol in gasoline, it may be the lesser of two evils. Before they started using ethanol, they used to put this horrible stuff that smelled funny and gave you cancer in it. I forget what its called now, but I recall that it was a bunch of letters. I think the purpose was that it made the gas burn with fewer emissions. I'm pretty sure that ethanol does the same thing which is why they don't use it anymore.

[Snake]

Blue, that was a great article. Thanks for sharing.

[ChaoSS]

Originally Posted by Jiggles

Actually a lot of stations have 91 that is no ethanol and 87 that is 10%. If you look at the pump it will tell you.

Not necessarily, California does not require the ethanol content to be disclosed. For the most part, it's a good idea to do your own research into what has ethanol and what doesn't.

Originally Posted by n4mwd

Its not the same as a diesel. A diesel doesn't even have a fuel charge when it compresses so there can never be compressive pre-detonation in a diesel. Diesel fuel does burn significantly slower than gasoline so if it had an octane rating, it would be way higher than 87.

That's not really correct, because you are confusing the slow burning with the "slow to burn".

Diesel may burn more slowly, but that's not what octane is. Octane is the resistance to starting burning under compression. Since, as you say, it compresses and then injects the fuel, it can have a very low octane and function just fine. In fact, the searches I have done say that if it did have an octane rating, it would indeed be very low.

That being said, diesel runs under extreme pressures, and a higher octane diesel would probably work just fine.

[Jiggles]

Originally Posted by ChaoSS

Not necessarily, California does not require the ethanol content to be disclosed. For the most part, it's a good idea to do your own research into what has ethanol and what doesn't.

You shouldn't expect to find no ethanol in CA...