Octane On A Jdm Motor

[karizmah]

ok, i figure i'd ask this noob question before i did the swap. Is it nescessary to use a higher octane gas on a jdm motor? A friend told me he thinks so but i don't know.
The motor is a b18c.

[jdk915]

Well i believe the compression ratio is higher on the JDM engines, therefor you would need at least 90 octane. My friend with a Del Sol Vtec ( b16) uses 91 octane, so i would think since the motor has Vtec you would want to use better gas.

[karizmah]

Would it be ok to use a premium fuel? like 94 octane or is that to high?

I found this info on another site is this true?

japan uses research octane number (RON) and the US uses motor octane number (MON)

Motor Octane: 96 =
Research Octane: 104

[98ex2286]

well with a higher compression ratio you need to use higher octane gas. premium should be fine i dont see the harm in it.

[Calesta]

Originally posted by karizmah@Oct 9 2004, 10:24 PM
Would it be ok to use a premium fuel? like 94 octane or is that to high?

I found this info on another site is this true?

japan uses research octane number (RON) and the US uses motor octane number (MON)

Motor Octane: 96 =
Research Octane: 104

Nope. The USA uses (RON + MON) / 2. Look at the sticker the next time you fill up at the pump. It'll say "R+M/2".

[karizmah]

so that would be 96+104/2=100?

100 what? Would that be mon

[Calesta]

No, one number is RON and another is MON. MON is typically quite a bit lower than RON. Your standard 91 octane gas rating in the US is the average of the RON and MON figures for the gasoline you're putting in your car. I don't know what the exact RON and MON values are for standard USA gasoline.

[karizmah]

so i suppose than that it would be as 98ex said. just use a higher octane fuel. 91 or 92 here.

[illicon2003]

not neccessarily true.. detonation could be due to 1000 different things....but generally speaking.. run the lowest octane you can with out knocking...high octane is just harder to ignite and it's a waste of money if you don't need it..

[Calesta]

Exactly. If you can run it on 87 and not get any detonation, do it. Most Honda engines are pretty happy with 89 octane in factory trim.