Octane Question
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Club Member
Joined: Aug 2008
Posts: 479
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From: In the flatlands!
Octane Question
Question is: Does high octane fuel burn faster or slower than low octane fuel?
Keep in mind I'm asking about street fuel, street fuel as purchased at your local service station.
Keep in mind I'm asking about street fuel, street fuel as purchased at your local service station.
Cruiser
Joined: Apr 2009
Posts: 137
Likes: 0
From: Dania Beach, FL
For the best performance, use the lowest octane that doesn't cause pinging (detonation). The lowest octane has has a lower flash point, meaning it burns quicker and more efficient. Higher compression motors need more octane to prevent pinging, or detonation, which can bend connecting rods and possibly damage cranks in high performance motors. My HD likes 93 while the 'Busa loves 87.
Road Warrior
Joined: Dec 2008
Posts: 1,810
Likes: 4
From: Out and about
Yup, I need 92+ in my HD, but I've owned a long list of sportbikes that I never ran anything but 87 in them.
For the best performance, use the lowest octane that doesn't cause pinging (detonation). The lowest octane has has a lower flash point, meaning it burns quicker and more efficient. Higher compression motors need more octane to prevent pinging, or detonation, which can bend connecting rods and possibly damage cranks in high performance motors. My HD likes 93 while the 'Busa loves 87.
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Road Captain
Joined: Aug 2009
Posts: 619
Likes: 3
From: In Garage
I've owned sport bikes to and ran low octane on 14:1 engine.
you can due that because of the cam timing. Bleeds off enough cylinder pressure to make a 14:1 engine have 170 psi in the cylinder when cranking. Of course they also red line at 14,000 rpm. : 0
you can due that because of the cam timing. Bleeds off enough cylinder pressure to make a 14:1 engine have 170 psi in the cylinder when cranking. Of course they also red line at 14,000 rpm. : 0
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Road Warrior
Joined: Nov 2007
Posts: 1,984
Likes: 7
You gotta remember there is a burn rate--speed involved. The actually time the flame front takes to do its job.
This has a lot to do with the timing. And the octane needed.
Sport bikes mostly have multi cylinders that are much smaller. Some even have two sparkplugs.
Harleys have much bigger cylinder diamnters, Mine is almost 4.00 inches. Also air cooled.
Hard to compare big air cooled cylinders with small liquid cooled cylinders.
This has a lot to do with the timing. And the octane needed.
Sport bikes mostly have multi cylinders that are much smaller. Some even have two sparkplugs.
Harleys have much bigger cylinder diamnters, Mine is almost 4.00 inches. Also air cooled.
Hard to compare big air cooled cylinders with small liquid cooled cylinders.
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