You cant prove that and hondata proves that MBT timing happens with high octane of 91/93 R/M.

Hondata:
1. Using a (very) high octane fuel, the engine is tuned to find the ignition timing which makes the most power. This is called 'mean best torque' (MBT) ignition timing.
2. Using 100 octane (RON) fuel, the engine is tuned to find the maximum spark advance before any knock is likely. This is called the 'knock ignition limit'.
3. Using 90 octane (RON) fuel, the engine is tuned to find the maximum spark advance at this octane. This gives the low octane knock limit ignition advance. The reason 90 and 100 octane is used (approx 85 and 95 octane r+m/2 method) is because this is the likely range of fuel octane the engine will used with.

 

Here we go... I knew I shouldn't have mentioned it...

 

Others already did. You were there.

 

 

89 is a lot different then 87. Sorry Subie but a lot of the problems described is caused by gasoline, not that high octane will fix what is broken but helps prevents it.

 

No prob SB! I'm with you there...

 

What does "89 is a lot different than 87" mean?

The standard for regular gas in Japan is 89RON. This is equivalent to 84AKI here (using (R+M)/2 and a .95 conversion factor). So if you mean Honda designed the Fit for "a lot" lower octane than is available here, you would be right. High octane will prevent damage from knocking in a car that needs it. The Fit isn't it.

Honda Japan says in the owners manual you may use higher octane, but the difference in performance is not significant. (link to somewhat fractured google translation).

To the OP: definitely, try a tank or 3 of hi-test. It will unlock the hidden potential of your econobox. Potential Honda and Big Oil can't tell you about.

 

Japans regular is our premium. 95 ron. Octane rating - Wikipedia, the free encyclopedia

 

I don't know what MOR (motor octane rating) is but would this online conversion tool help clarify differing opinions?

Octane Information And Calculator

 

Someone edited wiki. Prior to June 7 it said 89RON was regular. Coincidence? You'll note I gave the same cite along with the pertinent standard JIS K 2202 on May30. Here's another link to the standard stating 89RON. Want me to change it back?

Edit: the japanese wiki (translate using google if you wish) shows regular (fuel #2) as being 89RON since 1986. The latest standard was published in 2007. Before 1986 it was 85RON.

 

Not really.

It's just the average between RON and MON (R+M)/2. In Japan they don't test/publish the MON rating so extrapolation requires a "fudge" factor. 95% of the RON rating is what is generally used.

The point is that the standard in Japan JIS K2202 requires a minimum of 89RON for "regular" (and 96RON for premium) regardless of what someone edited wiki to say. The equivalent here is someone less than 89 for regular. 0.95*89=84.55, less than the minum standard for regular here (at least at lower elevations).

 

Something is missing in the translation. They do not say RON.

Here is something about 100 RON in 1986. JAPAN FIRMS TO LAUNCH SALES OF 100 OCTANE GASOLINE

So if your getting 35 mpg on regular and then use premium and get 39 or higher is that a waste of money? There is a reason 100 ron sales jumped up over 300 percent in '86 from 6 percent to 20 percent. Keep in mind that ecu was tuned to their 95 RON regular fuel.

 

Japan doesn't use (R+M)/2. In US publications we often don't see "87AKI using (R+M)/2 method." Check this page, it specifically states 89RON for fuel type 2 (regular).

If you are getting 35mpg and jump to 39 using premium it's not a waste of money so long as premium is less than 11% more than regular. What did you expect me to say?

You're a good consumer, Bullet. It's ok.

 

So coming home from work today my tranny started holding in 4th gear (no torque lockup) even though I had the shift lever in drive! Heading up a hill and it simply would not engage 5th gear cresting the hill or the lockup converter. WTF Honda?????

 

MY God......Your Fit knows that you hate it.......Get out while you still can



Or use Ye Old Warranty

 

The lockup disengages during power situations like going up a hill and getting up to speed. Buy another car because clearly this car isn't going to make you happy because it will downshift.

 

You clearly are an imbecile. The car would not disengage from the gear it was in AT ALL.
Now say there isn't something wrong with my car. Yeah that's right, a Honda Fit with barely over 8000 miles on it. Explain it. Go right ahead. You too Krunk. Since Honda could you know, NEVER have a flawed car come out of their factory. Fucking blind loyalists. Holy shit.

 

Lacking data on incline, speed, throttle position, etc it's hard to say if that's a problem or not. Depending on situation, the TC will not engage and not shift into highest gear. Especially situations like going up hill and then getting up to speed. A gear box that works like that is clearly unacceptable to you. You should get rid of the car.

 

I'm looking outside at my MT Fit right now....I might go for a leisurely drive. OP if we cant help you and you wake up tomorrow morning still not liking the car common sense says that you should sell it. You seem to have already condemned the car any way. You dont like it so your gonna keep finding faults with it

 

Would you ever consider another car that gets just as good fuel mileage as the Fit, yet is larger and has more power? I'm not auto tranny fan myself, so let's leave that out of the equation. Would you?