S2000 Octane
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From: Hong Kong
Originally Posted by mjb120,Mar 21 2008, 08:50 AM
wow so premium there is only 91?
in australia 91 is the lowest(normal unleaded) .. then 96 .. then 98. (shell vpower)
whether or not octane readings are different, i dont know ..
in australia 91 is the lowest(normal unleaded) .. then 96 .. then 98. (shell vpower)
whether or not octane readings are different, i dont know ..
In fact, I think we don't get anything below 96 nowadays
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From: Omaha NE
Originally Posted by mjb120,Mar 21 2008, 08:50 AM
wow so premium there is only 91?
in australia 91 is the lowest(normal unleaded) .. then 96 .. then 98. (shell vpower)
whether or not octane readings are different, i dont know ..
in australia 91 is the lowest(normal unleaded) .. then 96 .. then 98. (shell vpower)
whether or not octane readings are different, i dont know ..
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Originally Posted by shy_guyAP1,Mar 20 2008, 01:28 PM
Lower octane burns quicker, with such a high CR (11:1) you want something that burns slower (Higher Octane). If you have fast burning gas it can be completely burnt before the piston reaches TDC (Top Dead Center; the top of the stroke), when this occurs it is called "detonation" because there is incredible forces working against your engine and usually it leads to catastrophic failure. The knock sensor should adjust timing so that it all burns up, but not before reaching TDC.
I spun a rod bearing two years ago in my civic because of this, I was running 93oct but advanced my timing a bit too far and boom! (Well actually it was silent, but the aftermath wasn't).
Not an expert but did I hit the nail on its head?
I spun a rod bearing two years ago in my civic because of this, I was running 93oct but advanced my timing a bit too far and boom! (Well actually it was silent, but the aftermath wasn't).
Not an expert but did I hit the nail on its head?
Detonation is what they are trying to advoid with the high CR motors. But then the timing has to be set to the octane due to the slower speed of the burn and the short time available in the power stroke at high rpm. Our kart motors ran on 100 to 110 octane and had to be set for max cylinder pressure at about 10 degrees pass TDC. Set timing for the wrong octane and get max pressure before or at TDC and you are just hammering your bearings. You couldn't just use higher octane and assume you were getting more power. The timing had to match the octane.
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From: Hong Kong
Originally Posted by mxt_77,Mar 21 2008, 10:50 AM
RON vs MON. They use different rating methods.
Anyway, actually turns out where I live require at least 98 octane (usingt he RON rating). Which is approximately 94-ish using (R+M)/2 rating that US uses.