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87 Octane seems to work just fine
- Thread starter vito1943
- Start date
BajaRon
Well-known member
More than you wanted to know about Octane.
I am about to bore you with a long dissertation. So be forewarned.
There are so many misconceptions and myths surrounding Octane. Including what it is and what it does. But at least some of it is understandable. Because higher octane is required in higher output engines, people assume that Octane produces more power when this is actually not true. What higher octane does is allow engineers to build higher output engines without blowing them up.
Gasoline, type for type, quality for quality, will have the same stored energy potential, regardless of octane rating. Ethanol fuel has a lower stored energy component due to ethanol producing less energy than gasoline. Still, the energy potential, apples to apples, will be the same regardless of octane.
Higher compression gives engineers the ability to provide greater power output from the same engine. Other things need to change to take full advantage of this higher compression, but you get the idea. Higher compression creates more heat, because as you compress a gas (Air, fuel mix, etc.) you also heat it up. This is why the pipe going from your shop compressor to the tank gets very hot. This happens with no combustion at all. And your shop compressor is running at a lower compression than your Spyder engine.
A diesel engine runs at much higher compression than a gasoline engine because diesel fuel is very hard to ignite. The increased heat from compression is actually used to fire the fuel with no need of a spark plug. But high compression in a gas engine will fire the fuel as soon as it is injected. And because gasoline is so prone to explosion with heat, it is necessary to control this event with spark ignition from the spark plug. This requires that the gasoline not explode prematurely due to heat above it's ignition point. And this is where octane comes in.
Simply put - octane helps gasoline resist ignition at higher temperatures. The higher the octane, the higher the temperature it can withstand without exploding. And when it does explode, it burns at a slower rate than a lower octane fuel. The same energy is produced, but over a longer length of time. The difference is small on a time scale, but these factors are critical to running a high compression engine at peak efficiency.
Using lower octane fuel than recommended means you need to cool things down or you're going to damage your engine when the gasoline explodes too early. Before computers, that's exactly what happened. But now, your computer retards ignition to accomplish the necessary cooling of the combustion chamber. It does this by having your spark plug fire later than it should. This creates the opposite effect of compression.
Compressing a gas causes heat. Expanding a gas creates cool. That's how your air conditioner works. The compressed freon is pushed through a venturi into a larger space where it instantly cools as it expands. The same principle applies as the piston goes past Top Dead Center and starts it's travel downward. The fuel air mixture begins to expand into the now larger space created by the descending piston and the gas cools. All in an effort to have the gasoline wait for the spark plug to ignite the mixture.
The computer does not detect octane levels. Instead, it watches for the very tiny signs that the fuel mix is beginning to ignite prematurely. It makes instant adjustments before any damage is done.
BRP claims that the computer samples some systems at 20,000 a second. That's pretty good reflexes.
I am about to bore you with a long dissertation. So be forewarned.
There are so many misconceptions and myths surrounding Octane. Including what it is and what it does. But at least some of it is understandable. Because higher octane is required in higher output engines, people assume that Octane produces more power when this is actually not true. What higher octane does is allow engineers to build higher output engines without blowing them up.
Gasoline, type for type, quality for quality, will have the same stored energy potential, regardless of octane rating. Ethanol fuel has a lower stored energy component due to ethanol producing less energy than gasoline. Still, the energy potential, apples to apples, will be the same regardless of octane.
Higher compression gives engineers the ability to provide greater power output from the same engine. Other things need to change to take full advantage of this higher compression, but you get the idea. Higher compression creates more heat, because as you compress a gas (Air, fuel mix, etc.) you also heat it up. This is why the pipe going from your shop compressor to the tank gets very hot. This happens with no combustion at all. And your shop compressor is running at a lower compression than your Spyder engine.
A diesel engine runs at much higher compression than a gasoline engine because diesel fuel is very hard to ignite. The increased heat from compression is actually used to fire the fuel with no need of a spark plug. But high compression in a gas engine will fire the fuel as soon as it is injected. And because gasoline is so prone to explosion with heat, it is necessary to control this event with spark ignition from the spark plug. This requires that the gasoline not explode prematurely due to heat above it's ignition point. And this is where octane comes in.
Simply put - octane helps gasoline resist ignition at higher temperatures. The higher the octane, the higher the temperature it can withstand without exploding. And when it does explode, it burns at a slower rate than a lower octane fuel. The same energy is produced, but over a longer length of time. The difference is small on a time scale, but these factors are critical to running a high compression engine at peak efficiency.
Using lower octane fuel than recommended means you need to cool things down or you're going to damage your engine when the gasoline explodes too early. Before computers, that's exactly what happened. But now, your computer retards ignition to accomplish the necessary cooling of the combustion chamber. It does this by having your spark plug fire later than it should. This creates the opposite effect of compression.
Compressing a gas causes heat. Expanding a gas creates cool. That's how your air conditioner works. The compressed freon is pushed through a venturi into a larger space where it instantly cools as it expands. The same principle applies as the piston goes past Top Dead Center and starts it's travel downward. The fuel air mixture begins to expand into the now larger space created by the descending piston and the gas cools. All in an effort to have the gasoline wait for the spark plug to ignite the mixture.
The computer does not detect octane levels. Instead, it watches for the very tiny signs that the fuel mix is beginning to ignite prematurely. It makes instant adjustments before any damage is done.
BRP claims that the computer samples some systems at 20,000 a second. That's pretty good reflexes.
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Redbeard
Active member
Something I do notice when I run 93 octane is this: The 1330 engine in my RT shifts nicer! I don't quite understand why but it is enough for me to continue to run high octane fuel. I check my milage with every fill up (actual milage/gallons used) and there is zero difference between any grades of gasoline I use. I am surprised the comuter estimated milage usually is very close to actual fuel use. Generally within 1 mpg.
safecracker
Well-known member
I ran 87 in my old Spyder (V-Twin) for 96,000 miles and I have 36,000 miles on my 21 Spyder and all she gets is 87. Runs fine and I ride 2 up 95% of the time. Bruce
bikerchris1270
Active member
With the current price of fuel, Premium being north of $5/gal, how many of you have gotten away with 87 octane fuel with no issues? I start thinking of doing a trip somewhere and my thoughts drift toward a 2nd mortgage to afford hotel and fuel… not to mention food.
Calimusjohn
Active member
I've run on 87 for thousands of miles. No problem. I use 93 on days where performance is desired.
Woodaddict
Well-known member
I was using 87 octane. But on start off I would hear a couple of pings, so I went back to 93. Something about taking off at low RPM would let it ping. Not worth taking chance to start engine damage
troop
Well-known member
Chris,
Didn't you get a Monster stage 1 flash? If so, what does Monster say about that? On my past 2019 F3S and current 2022 RT S2S, I have custom tunes made with Dyno Jet Power Vision devices. These maps require the use of 91 octane. This device also allows me the option of flashing in the BRP stock fuel tune. While still being "recommended" by BRP, 87 octane is still the minimum fuel requirement. With the stock tune, I haven't noticed any butt dyno difference between 87/91 fuel. I am actually pondering going back to the stock tune due to the $1.10 difference between a gallon of 91 and 87. Maybe flip/flop between 87/91? At least still get lower ethanol content than straight 87.
Didn't you get a Monster stage 1 flash? If so, what does Monster say about that? On my past 2019 F3S and current 2022 RT S2S, I have custom tunes made with Dyno Jet Power Vision devices. These maps require the use of 91 octane. This device also allows me the option of flashing in the BRP stock fuel tune. While still being "recommended" by BRP, 87 octane is still the minimum fuel requirement. With the stock tune, I haven't noticed any butt dyno difference between 87/91 fuel. I am actually pondering going back to the stock tune due to the $1.10 difference between a gallon of 91 and 87. Maybe flip/flop between 87/91? At least still get lower ethanol content than straight 87.
Albec
Well-known member
I prefer to run the high-octane, factory recommended, stuff myself. Around here the price difference is around a dollar a gallon, so about $7 more for a full tank, assuming the tank is near empty.
Better safe than sorry and at $7, I can afford it.
For me, if paying $7 more for a tank of gas is going to break me, then it's time to get rid of this toy.
Better safe than sorry and at $7, I can afford it.
For me, if paying $7 more for a tank of gas is going to break me, then it's time to get rid of this toy.
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Right on! If you can't afford to pay, then don't play.
bikerchris1270
Active member
Good memory sir, yes, I did do the ECU modification. I’ll continue to run 91+ fuel avoiding ethanol . I asked the question being curious of what others do. Like others say, you wanna play, you gotta pay. Cheers!
I have Stage II and carry a small bottle of Boostane in my trunk. It takes 2.61 oz. to turn 6 gallons of 87 octane into 91 octane. $12.00 for a 4oz bottle. Boostane apparently has a shelf life of 2 years if unopened and stored properly. I'm guessing my trunk is almost properly.
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Woodaddict
Well-known member
The price difference gap between 87 and 93 is always the same gap within pennies, so why are you riding even with 87 being so high. Asking for a friend...
I ran one tankful of 87 in my '24 Spyder RTL, just to see what would happen. There have been times in my motorcycling journeys that 87 was all I could get, and I wanted to know ahead of time how my Spyder would run on it.
It did fine, I could not tell any difference between 87 and 93. I didn't get any pinging, and couldn't detect any lack of power.
But I'll still keep using 93 since that is what the engineers said it should have.
It did fine, I could not tell any difference between 87 and 93. I didn't get any pinging, and couldn't detect any lack of power.
But I'll still keep using 93 since that is what the engineers said it should have.
BajaRon
Well-known member
Compression ratio on the 1330 is 12.2 to 1. It is 10.8 to 1 on the 998 V-Twin. Surprisingly, the 1330 is more forgiving on fuel octane than the 998. My guess is that the fuel management system has been improved to compensate better than the older V-Twin. But both will run just fine on 87 octane in stock configuration. Ethanol fuel creates a higher incidence of problems than the octane question. This is universal regardless of octane rating.
But there are caveats, of course. If you have an ECU tune, you’re going to need to stick with at least 91 octane.
If you are running high altitudes, (typically, above 4,000 feet) you may find nothing above 87 octane. You may be looking at 85 or 86. Which above 4,000 feet will also run OK in a stock engine. You’ll need to consult your tuner (if you run one) to get recommendations for high altitude.
As already mentioned, if I were running a tune, I’d have a bottle of Octane Booster along so I didn’t get caught under octaned.
But there are caveats, of course. If you have an ECU tune, you’re going to need to stick with at least 91 octane.
If you are running high altitudes, (typically, above 4,000 feet) you may find nothing above 87 octane. You may be looking at 85 or 86. Which above 4,000 feet will also run OK in a stock engine. You’ll need to consult your tuner (if you run one) to get recommendations for high altitude.
As already mentioned, if I were running a tune, I’d have a bottle of Octane Booster along so I didn’t get caught under octaned.
bikerchris1270
Active member
Yes, when I travel, I do carry a couple of bottles of octane booster. Like you say, sometimes you do not have a choice of fuel grade.
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