Also remember, with 600 miles on the Odo, the engine isn't broken in yet so you should be varying the rpm's a little more. Give'r some rev's... she'll love it... but wait until the car's warmed up.

~SB

 

Owners manual states break-in period as 600 miles. It also states to avoid full-throttle starts and rapid acceleration. How long do think the break-in should be? Any other advice on breaking in the 2010 fit AT?

 

Officially, yes the break in is 600 miles but I found that the engine continued to smooth out through about 2000 miles. My altima didn't achieve it's best performance/economy until after about 6k miles...

Avoiding mashing the gas is definitely a good thing but 4k or 5k rpm doesn't need to be achieved by attempting to obtain the best 0-60 possible. Slow revs up or longer delays before shifting (you have a sport AT?) are not only good but can be fun (especially in the twisties).

~SB

 

The honda fit has an adaptable tuning ecm. You can run regular, or premium your car will adjust because of the knock sensor. Premium will burn cleaner and make your car more efficient. Winter is not the time to talk about mpg. Just run what ever gas you want and drive the car the way you will all the time dont baby it because the ecm would learn the way you drive and the ecm will give more timing as miles go on. If you dont like your mileage try different gasoline. Check this out http://www.ethanol.org/pdf/contentmg...inal_12507.pdf

There is convential and reformulated gas out I wish we had convential with out ethanol.

 

Of note, Premium does not burn any cleaner than regular and it is not more efficient unless used in a car designed for premium, it simply has a Higher Anti Knock Index rating. The Detergents in the fuel is what will help "clean" the engine, not the octane rating. This depends more on the brand of gas you buy than the octane rating. Most gas stations that have detergents in fuel have it in all octane ratings but occasionally, you'll find a brand or station that advertises these detergents in their Premium and not their regular. Also, in regards to the timing. The fit is Designed to run on regular so the timing should be pretty close to optimal on Regular. The engine would retard timing if a lower octane gas than regular (87) was used and technically advance timing if a higher octane gas was used. Since the fit is running almost at it's peak on regular, the engine can't advance timing much, it can only effectively retard timing (which wouldn't make sense when using a higher octane). If the L15 in the Fit had a higher compression ratio and was designed for higher octane and you used a lower octane rating, you'd see a seriously noticable perfromance improvement by bumping back up to Premium. In this case, the engine is not as it is only a 10.4:1 compression ratio. (Not low, but not High either like the Civic Si - 11.0:1)

~SB

 

Patience wasn't the issue--- tact and diplomacy were. The post wasn't directed at you but rather, anyone on here who *might* be using less accurate methods to calculate their fuel economy. But you seemed to take it personally.

The method I use may not be scientifically accurate within one decimal point, but it certainly provides the degree of accuracy necessary to determine if your car is getting anywhere near advertised fuel economy.

And in the case of Canadian gas stations' practice of putting those little stickers on their pumps that read "volume corrected to 15 degrees celsius" it also helps determine which stations are best to buy from--- or avoid. I've gotten consistent results from those I frequent vs. others.

 

I'm now happy to report a 20% increase in mpg from my first few tanks with 2287 miles now on my Fit.

Last tank yielded 34 mpg with the previous tank yielding 35.4. The tank before that was 31.6 and the first two tanks were 29. I no longer feel like my previous Toyota was better in mileage. My Fit has now surpassed its best mpg performance.

I was not expecting this high an increase this soon but it did happen with no difference in driving conditions.

I'm hoping to see a further increase as I cross 5000 and 6000 miles, especially after my first oil change. More to come.

 

yeah, I had the same thing happen around the 3K mark. Entirely anecdotal, but it seemed to improve from one tank to the next. Power too.

 

Premium gas does burn cleaner and it is made of mostly of saturated hydrocabons and is carbon nutural. Look at your tail pipe, My tail pipe is clean with 30000 plus miles. Timing is mainly by engine design and only changes when parts wear out or when engine is modified. With premium the ecm will run in a higher map which mean higher efficiencies(vacuum). 10.4 compression is high and if you had a v8 motor you would need 100 octane. For emissions the car is set up to run 14.7(Lombard) and if the car was set like a BMW when you nailed it would go rich to 12.5 for max horsepower. The Fit builds a map for long term adjustment which means it looks at that map for most full throttle uses, because of drive by wire. Gasoline in a car is only 34% efficient the rest goes out the tail pipe and cooling system so if you make your car more efficient by running premium then less is going into cooling,tailpipe. Even if your car runs fine on regular sometime down the road it will need premium. Most cars have a 9.5:1 compression with a static compression of 8.1 which is made for regular. Hondas are about 90%engine efficient so it static compression is 9.4 which is 89octane high side or premium low. An additive could be any single ingredent ethonal,toluene,iso octane, triptane etc. and 1 percent could change the whole gas properties. In f1 racing they can add 1% of different additives for more power,mileage,etc.

 

My tail pipe is clean as a whistle, thank you very much.

Anecdotal evidence points to added deposits running premium fuel (at least around the exhaust valves).

Give it up, will you?

 

ok.. NO! Premium does not burn any cleaner (and my tailpipe is just super clean).
Reading: Ethanol FAQs - Wind Farm & Ethanol Plant Development, Alternative Energy Investments, Renewable Energy - EcoGen: Investing In New Energy - ecogen-energy.com

10.4 is not a high compression. is it higher than many other engines out there? Yes. is it High? No. Power is obtained by the compression ratio of the engine and not the octane level of the fuel. The maximum compression of the fit is 10.4 when the fuel is combusted. If you use Regular... the compression used is about 10.4, premium... 10.4. because there is no difference in compression whether it is regular or premium... there is no additional power. Since the Fit's L15 is a little higher compression than most 4cyl engines, the timing might be retarded slightly by the computer resulting in a slightly less than optimum compression ratio during combustion. In this case a bump in octane might result in an optimum ratio (vs a slightly retarded level) which may result in a SLIGHT performance gain. 10.4 for a V8 would be high... but not for a 4cyl. (B Series VTEC and K Series iVTEC motors are running higher compression in many applications - Not to mention the B series VTEC is coming up on being 20 years old.)

The increased performance that I described is loaded with "If"s and "might"s all ending in the possibility of a "Slight" performance gain.

I'm not saying there's no chance at better performance, what I am saying is there is a Minimal chance with only Negligible improvements... and still of note, I'm obtaining similar economy and sill using Regular. Last calculated was 40mpg and still averaging over 37mpg with 0 highway miles and no hypermiling.

~SB