What Type Of Gas Do Ya'll Use?

I never understood those who use 91 in bikes that runs on 87. Wasted money and will probably run better with 87 since thats what the bike is tuned for.
 
Pigs said:
I never understood those who use 91 in bikes that runs on 87. Wasted money and will probably run better with 87 since thats what the bike is tuned for.
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I run 89 (R+M/2) even thought mine can take 87. And I can easily explain why.

Sportbikes run high compression engines and are tuned for power with much less stress than say a car. Weight and all considered. If you drive the bike off of the lot and put 87 in it, it's perfectly fine.

However, mine isn't stock. The intake snorkel was removed before I got it and it has a reusable filter in it, both of while change the airflow into the engine. I've disabled the PAIR system, changing the emissions around. I've swapped the exhaust, changing the back pressure in the system. I've bypassed the factory timing retard in lower gears, changing the way the power is delivered.

All of these things mean that it's not running like it did when tuned in a stable factory environment. So, I have two choices to ensure engine safety ... retune the engine, or increase the knock resistance of the fuel to prevent detonation.

Eventually the engine will be tuned properly, but for now I'm reducing the chance of knock with increased octane rating due to engine modifications. If I'm running lean with the mods, the fuel helps protect the engine.

Octane ratings simply measure knock resistance. If knock/detonation is a possibility, especially on a high-strung engine, use a higher octane fuel. Yes, there is some buffer in the factory tune, but it's there to account for minor variations in weather and fuel mix, not a completely different intake and exhaust setup.
 
The biggest problem I have found, was my bike was pinging on 87. Especially when on the summer blend. No ping or pop on 91. Bike runs great on winter blend any octane. Anyone else in California have this problem?
 
MattW said:
I run 89 (R+M/2) even thought mine can take 87. And I can easily explain why.

Sportbikes run high compression engines and are tuned for power with much less stress than say a car. Weight and all considered. If you drive the bike off of the lot and put 87 in it, it's perfectly fine.

However, mine isn't stock. The intake snorkel was removed before I got it and it has a reusable filter in it, both of while change the airflow into the engine. I've disabled the PAIR system, changing the emissions around. I've swapped the exhaust, changing the back pressure in the system. I've bypassed the factory timing retard in lower gears, changing the way the power is delivered.

All of these things mean that it's not running like it did when tuned in a stable factory environment. So, I have two choices to ensure engine safety ... retune the engine, or increase the knock resistance of the fuel to prevent detonation.

Eventually the engine will be tuned properly, but for now I'm reducing the chance of knock with increased octane rating due to engine modifications. If I'm running lean with the mods, the fuel helps protect the engine.

Octane ratings simply measure knock resistance. If knock/detonation is a possibility, especially on a high-strung engine, use a higher octane fuel. Yes, there is some buffer in the factory tune, but it's there to account for minor variations in weather and fuel mix, not a completely different intake and exhaust setup.
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intake/exhaust mods have no bearing on what octane fuel you'll need. Don't know much about ignition timing. But if all you did was advanced the timing in the lower gears, then how is it different than when you are in high gears.
 
Pigs said:
intake/exhaust mods have no bearing on what octane fuel you'll need. Don't know much about ignition timing. But if all you did was advanced the timing in the lower gears, then how is it different than when you are in high gears.
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I used to make a living tuning ECUs. Intake and exhaust absolutely change the way the engine runs.

Intake mods easily shift the fuel mix and can cause a lean condition which can lead to detonation. Exhaust mods shift the mix due to pressure differences during cam overlap and back pressure changes with high exhaust volumes. Exhaust is less of an issue though.

More timing in lower gears is not only experienced at different loads, the bike also revs faster, which can cause the ECU to reference different cells than higher gears simply due to the sample rate of the data.

Anything that changes air or fuel delivery, or the way the air or fuel is measured, impacts the tune and chance of detonation.
 
Haha I actually made a video about this asking people. i've gotten mixed answers still but from what i understand ethanol isn't horrible as long as it isn't put in your bike and it sits for a while- If your riding regularly and the ethanol will run through quick it shouldn't have a chance to eat into your pipes on the bike etc.
 
Matycyclez said:
Haha I actually made a video about this asking people. i've gotten mixed answers still but from what i understand ethanol isn't horrible as long as it isn't put in your bike and it sits for a while- If your riding regularly and the ethanol will run through quick it shouldn't have a chance to eat into your pipes on the bike etc.
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Yeah, ethanol is corrosive to a degree, but it's so diluted in pump gas it causes no real issues on fuel injected engines. I even run E85 in my car and I've had no issues after several years.

Ethanol does cause fuel to go bad a little faster, and can play hell on carbureted vehicles. The older low pressure fuel lines tend to break down and harden more easily than modern reinforced lines. And the change in stoicheometric ratio of the fuel itself can require a re-jet to run properly. Most fuel injected engines run an O2 sensor to adjust for the slight AFR change, but carbs don't have that option.
 
You should be running as high of octane as you can get to prevent pre detonation. Most of your motorcycles are going to have a higher compression so it is very important to run as high of octane as possible.
 
I use 95 for normal road use, but 98 if the price is low enough.
We don't have any lower octane :')
 
I honestly have no idea, but it can contain about 5% max.
I have to say that the Euro95 (or super95) is 95RON, and is the same as 85MON
 
BurntRuber said:
That's because every other country but America cares about pre detonation
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It's not that. We calculate differently. The US rates octane as an Anti-Knock Index (AKI), which is calculated (RON+MON)/2. Other places just use RON or MON. European 95 is similar to US 89 I believe. Look at the pump next to the rating the next time you fill up and you'll see it noted.

US fuel contains up to 10% ethanol. Concentrations are highest in warmer months. Percentages usually drop a little with colder seasons due to ethanol's properties in low temps.
 
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the gas in the US is shit. if you want something higher then 93 your gonna pay atlas double for it. the e85 isn't even 85% ethanol its usually around 75% or less.
 
BurntRuber said:
the gas in the US is shit. if you want something higher then 93 your gonna pay atlas double for it. the e85 isn't even 85% ethanol its usually around 75% or less.
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Well, you're right that fuel above 93 is expensive, but our 93 is equivalent to Euro 100 and costs half as much.

And you're right about E85. It comes in three grades. The highest grade (only in warmer months) is minimum 79% ethanol I believe. The lowers grade (for really cold climates) is minimum 70%. Luckily, here in Alabama we only go down to the mid grade so I keep at least 75% ethanol and don't drop to 70%.

Now, US diesel was really bad up until recently.
 
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