Question about f22b - Honda Prelude Forum

jsmooney · 11-05-2002, 10:09 PM

A page comparing USDM Si and JDM Si Preludes

On this page you can scroll down until you get to the gas stuff and it say the required Octane is 100 ron (?).....but the gallon measurements are in UK gallons. Can someone explain what this means?

Thanks,
Jonathan

jsmooney · 11-05-2002, 10:10 PM

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Satan_SRV · 11-05-2002, 10:26 PM

Huh?

RON is a way they measure octane in Japan...so 100 octane.

US Gallon = 3.9 litres
UK gallon = 4.3 litres

And what does this have to do with the F22B? The Si has an H23a!

cantdrive55 · 11-05-2002, 10:36 PM

Quote:

Originally posted by Satan_SRV
Huh?

RON is a way they measure octane in Japan...so 100 octane.

US Gallon = 3.9 litres
UK gallon = 4.3 litres

And what does this have to do with the F22B? The Si has an H23a!

His car has an F22b, and ron (Research Octane Number) is a different way of rating fuel's octane. In the US, they use the (r+m)/2 method, the R is for ron, the M is for mon (Motor Octane Number) which is yet another method for rating the octane. By adding the two and dividing by two, you get the average. From the little research I did, I found that the Ron number tends to be higher than the mon number.

As for your situation, I'm sure the minumun 91 Octane specified for the H23 will be perfectly fine, the H23 has slightly higher compression than the F22b (taken from the link you provided) If the motor has more aggressive timing or something, then the ECU will compensate for slightly lower octane fuel anyway.

brendon2k · 11-06-2002, 12:28 PM

Quote:

Originally posted by cantdrive55

His car has an F22b, and ron (Research Octane Number) is a different way of rating fuel's octane. In the US, they use the (r+m)/2 method, the R is for ron, the M is for mon (Motor Octane Number) which is yet another method for rating the octane. By adding the two and dividing by two, you get the average. From the little research I did, I found that the Ron number tends to be higher than the mon number.

As for your situation, I'm sure the minumun 91 Octane specified for the H23 will be perfectly fine, the H23 has slightly higher compression than the F22b (taken from the link you provided) If the motor has more aggressive timing or something, then the ECU will compensate for slightly lower octane fuel anyway.

Yes Ryan is right the RON octane number is a decent amount higher. I think marcucci had a post about it a while back that pretty much stated that the high octane gas in japan that is over 100 is really just about the equivalent of 93-94 so its not like there gas is really better in anyway.

AccordSleeper · 11-07-2002, 05:49 AM

Quote:

Originally posted by brendon2k

Yes Ryan is right the RON octane number is a decent amount higher. I think marcucci had a post about it a while back that pretty much stated that the high octane gas in japan that is over 100 is really just about the equivalent of 93-94 so its not like there gas is really better in anyway.

yep my JDM H22 runs just fine on 93.