Ways to lower octane level in gas?
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Let it sit long enough especially in e10 or greater fuels. The motorcycle guys swear e10 premium starts after storage but truth is it becomes lower octane after settling
Too much octane does not reduce power, unless it's energy content is lower.
It still ignites the same and burns at the same speed, and provided the energy content is the same.
Diesel will do it, but it takes a bit...SAE90 gear oil will do it really quickly.
It still ignites the same and burns at the same speed, and provided the energy content is the same.
Diesel will do it, but it takes a bit...SAE90 gear oil will do it really quickly.
Originally Posted by Marco620
Let it sit long enough especially in e10 or greater fuels. The motorcycle guys swear e10 premium starts after storage but truth is it becomes lower octane after settling
Settling? What settles?
Let it sit long enough especially in e10 or greater fuels. The motorcycle guys swear e10 premium starts after storage but truth is it becomes lower octane after settling
Settling? What settles?
Shannow is correct, an unnecessarily high octane rating does not reduce power in and of itself unless the method to increase the rating is by using a additive that has a lower energy density than gasoline. But the problem isn't the octane rating as an isolated variable.
Too high of octane used in an application that does not need it DOES decrease power. It burns SLOWER which is why it works to control detonation in high compression, high RPM, boosted engines that need it.
I've been a part of the kart racing community for ages and can tell you for fact that low compression 4 cycle kart engines like the Briggs flat head and the Honda GX clones will LOSE power on high octane fuel. So many guys think "race fuel" or even 93 octane is best and find out that is absolutely not the case. It has been proven on our dynos many times.
Regular 87 octane fuel will burn faster and more efficiently in a low compression, low BHP application resulting in more power and better economy.
I've been a part of the kart racing community for ages and can tell you for fact that low compression 4 cycle kart engines like the Briggs flat head and the Honda GX clones will LOSE power on high octane fuel. So many guys think "race fuel" or even 93 octane is best and find out that is absolutely not the case. It has been proven on our dynos many times.
Regular 87 octane fuel will burn faster and more efficiently in a low compression, low BHP application resulting in more power and better economy.
No it doesn't in and of itself. There is a lot of lore about octane rating, most of which is complete fabrication and misunderstanding. It has a lot to do with how the apparent rating is obtained, there are many ways to do so.
What Shannow wrote is correct:
Originally Posted by Shannow
Too much octane does not reduce power, unless it's energy content is lower.
It still ignites the same and burns at the same speed, and provided the energy content is the same.
What Shannow wrote is correct:
Originally Posted by Shannow
Too much octane does not reduce power, unless it's energy content is lower.
It still ignites the same and burns at the same speed, and provided the energy content is the same.
Originally Posted by dlundblad
Adding water to E10 will separate everything as well as lower the octane level after it sits a while.
There's a nice YouTube video of a guy showing the process with water bottles.
That's how I make my own ethanol free fuel for my yard equipment. A little octane booster to bring it back up.
Adding water to E10 will separate everything as well as lower the octane level after it sits a while.
There's a nice YouTube video of a guy showing the process with water bottles.
That's how I make my own ethanol free fuel for my yard equipment. A little octane booster to bring it back up.
Originally Posted by racin4ds
Too high of octane used in an application that does not need it DOES decrease power. It burns SLOWER which is why it works to control detonation in high compression, high RPM, boosted engines that need it.
I've been a part of the kart racing community for ages and can tell you for fact that low compression 4 cycle kart engines like the Briggs flat head and the Honda GX clones will LOSE power on high octane fuel. So many guys think "race fuel" or even 93 octane is best and find out that is absolutely not the case. It has been proven on our dynos many times.
Regular 87 octane fuel will burn faster and more efficiently in a low compression, low BHP application resulting in more power and better economy.
I have to agree with this. In conversations with both ELF and Shell fuel representatives (years ago) both confirmed this was true, higher octane fuels burn slower (to combat pre-ignition) than lower octane fuels, and I am talking about 87 vs 91 or more octane.. My low compression 2 stroke outboard motor ran terrible on premium fuel, 87 octane only for proper performance.
Too high of octane used in an application that does not need it DOES decrease power. It burns SLOWER which is why it works to control detonation in high compression, high RPM, boosted engines that need it.
I've been a part of the kart racing community for ages and can tell you for fact that low compression 4 cycle kart engines like the Briggs flat head and the Honda GX clones will LOSE power on high octane fuel. So many guys think "race fuel" or even 93 octane is best and find out that is absolutely not the case. It has been proven on our dynos many times.
Regular 87 octane fuel will burn faster and more efficiently in a low compression, low BHP application resulting in more power and better economy.
I have to agree with this. In conversations with both ELF and Shell fuel representatives (years ago) both confirmed this was true, higher octane fuels burn slower (to combat pre-ignition) than lower octane fuels, and I am talking about 87 vs 91 or more octane.. My low compression 2 stroke outboard motor ran terrible on premium fuel, 87 octane only for proper performance.
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Two samples of straight gasoline with different octane ratings will have the same burn rate. This Sunoco article refers to it in regards to density but also describes how octane rating is affected by additives as opposed to just the branching of the hydrocarbon molecule:
https://www.sunocoracefuels.com/tech-article/beyond-octane
https://www.sunocoracefuels.com/tech-article/beyond-octane
E10 is a blend of gasoline and ethanol, the final product being whatever octane it's rated. Ethanol has higher octane than gasoline, and ethanol will blend with water (unlike gasoline). So if you add 9-10% water to E10 and the water/alcohol blend can be poured off, the remaining gasoline would be lower octane than what it was originally rated. Problem is determining exactly what that octane is.
Originally Posted by racin4ds
Too high of octane used in an application that does not need it DOES decrease power. It burns SLOWER which is why it works to control detonation in high compression, high RPM, boosted engines that need it.
I've been a part of the kart racing community for ages and can tell you for fact that low compression 4 cycle kart engines like the Briggs flat head and the Honda GX clones will LOSE power on high octane fuel. So many guys think "race fuel" or even 93 octane is best and find out that is absolutely not the case. It has been proven on our dynos many times.
Regular 87 octane fuel will burn faster and more efficiently in a low compression, low BHP application resulting in more power and better economy.
Your off base the correct answers are in this thread.
Too high of octane used in an application that does not need it DOES decrease power. It burns SLOWER which is why it works to control detonation in high compression, high RPM, boosted engines that need it.
I've been a part of the kart racing community for ages and can tell you for fact that low compression 4 cycle kart engines like the Briggs flat head and the Honda GX clones will LOSE power on high octane fuel. So many guys think "race fuel" or even 93 octane is best and find out that is absolutely not the case. It has been proven on our dynos many times.
Regular 87 octane fuel will burn faster and more efficiently in a low compression, low BHP application resulting in more power and better economy.
Your off base the correct answers are in this thread.
4WD
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If engines are not designed around a certain octane ... why is there movement for a universal (say 91) octane
Originally Posted by 4WD
If engines are not designed around a certain octane ... why is there movement for a universal (say 91) octane
Engines could be more efficient if they had 91 octane as a minimum. FWIW I use E-15 in my 2000 Mustang because it can ping a little with 87 and the E-15 is 89 octane. I still get right at 20 mpg and the pinging problem solved with E-15. I get about 21-22 with 93 octane E-10. I would think the octane can be raised cheaply by adding more ethanol to the blend and designing cars to run up to at least E20 or 30. That should get the 91 octane they want.
If engines are not designed around a certain octane ... why is there movement for a universal (say 91) octane
Engines could be more efficient if they had 91 octane as a minimum. FWIW I use E-15 in my 2000 Mustang because it can ping a little with 87 and the E-15 is 89 octane. I still get right at 20 mpg and the pinging problem solved with E-15. I get about 21-22 with 93 octane E-10. I would think the octane can be raised cheaply by adding more ethanol to the blend and designing cars to run up to at least E20 or 30. That should get the 91 octane they want.
Fill the tank with white gasoline. Or do they even make that anymore? I remember stations that had a small tank of white gasoline with a hand pump. Some used it as a parts cleaner because it didn't leave a residue.(Get out the Rawleigh Salve mom, I've had a little accident). Come deer season, there was a big run on white gasoline for Coleman lantern fuel as retail off the shelf lantern fuel was far off in the distance. About .16 cents a gallon in 1954.
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