Better read what Honda says about overfilling the tank! Big NO NO, you bad, 50 lashes with a wet noodle.

I no longer need to use premium gas, I ordered a 200 MPG carburetor from the back of a car book and a secret hi performance chip off Ebay. I get 200 MPG at 80 MPH with regular and 203 MPG with premium, not worth the difference.

 

Is that the same one with male enhancement devices? You might want to see if you can get your money back...

 

You been peeking, shame shame

 

I have been filling to the top for 5 1/2 years on this car with no problems.. In fact my car has never been to a dealership for any reason and no one but myself has turned a wrench on my car that I didn't check that it was properly torqued.... Your post is a classic example of the type of mindset that I mentioned in my earlier post... One idiot awhile back was accusing me of doing a misdeed by sharing my experiences...I haven't posted a thing about my observations and experiences with different octane grades of fuel here or anywhere else that isn't true.... There are a few of us boost junkies that even go as far as mixing our own secret concoctions to increase the octane of the stuff in the tank, and no I am not blowing smoke up anyone's ass....++++

 

Your post is a classic example of failure to read the f'n manual.

You sound like the pregnant teenager: "I done it lots a times and nuthin happened!!"

 

My post was not meant to be derogatory, simply to point out that self proclaimed experts are often very wrong and do very harmful things to their cars. I even tried to do it decently and not point out the glaring stupidity, lack of knowledge and lack of good judgement in your post. Asains refer to it as saving face. To treat another person with dignity and respect even if they do not deserve it.

The failure to follow the manual can result in damage to the pollution system and void the warranty.

Dangerous weapons should be removed from the hands of idiot's and fool's, I would start with keyboards!
JIm 0311

 

When using 87 octane fuel the ECU will adjust to it just as it will to higher octane fuel... You can disconnect the negative cable from the battery for a few minutes and reconnect it. to get the ECU to adjust to the fuel or driving style sooner... If you are happy with the way it runs on 87 octane fuel there is no reason to use anything else except an occasional fuel system/fuel injection cleaner... It is the people that drive mostly in a spirited manner or in heavy stop and go traffic like on a freeway in a large city that will benefit the most from higher octane fuel... Lower octane fuel will yield better fuel mileage figures on the highway and when a car is driven easily with a light load on the engine... Either way the ECU isn't going to advance the timing to the point where pinging occurs and damage is done unless the octane level is below 87... There are guys down here that contract to service the pumps on oil wells that ran their trucks on what is known as tap gas.. It is liquid natural gas that has for years been burned off to prevent a hazardous explosion... There is also a tap that can be opened to drain it into a gas can... The stuff is very low in octane but puts out a lot of power... It is hard to ignite as a gas in a cold engine so they have to use most of it up and fuel up at a gas pump before shutting off their engines.. I don't know if it is still used on today's ECU equipped cars but I know it was as recently as the late 1980s...

 

Just a question for proponents of higher octane fuel in cars that don't ask for premium recommended/only... would most engines see a benefit, or only some?

 

some, and again, you need to quantify "benefit". Are you looking for power? efficiency/MPG?

My thoughts, with a modern computer on a car that only requires regular as a minimum, you should gain near0 MPG benefit. So it's only about power. You're paying maybe 5% higher at the pump, you aren't going to get 5% more power. Perhaps also 0-4%.

Most of the time when you're going about your business, you're using maybe less than 50% of your car's available power anyway, so no difference there.

Only when you're flogging the engine at 100% and you need that extra 5% is where it comes into play.
For me this is the Fit during hill climbs.

 

In the case of the Fit it is stated under " Fuel Recommendation" "Your vehicle is designed to operate on unleaded gasoline with a pump octane number of 87 or higher. Use of a lower octane gasoline can cause a persistent, heavy metallic rapping noise that can lead to engine damage. Numerous people here on Fit Freak including myself have seen an increase in ignition advance by using 93 octane gasoline instead of the minimum octane rating of 87... Being able to ignite the fuel an earlier point in the compression stroke without detonation caused by the heat inside the combustion chamber due to high compression or hot carbon deposits improves the efficiency of the engine and increases power output... The engine control unit of the Fit detects very light detonation and backs off of ignition advance just enough to not induce ping or knock which is what you hear when there is detonation described as persistent, heavy metallic rapping noise, in the owners manual... When using higher octane gasoline the ignition advance isn't pulled back as far as it would be when using the lowest recommended 87 octane gasoline... I have never seen a maximum octane recommendation for any kind of gasoline engine since there has only been lead free gasoline being sold... It should be obvious that not having enough octane will damage your engine and there isn't a situation where there is too much octane that would cause problems.

 

With premium gas you will get more low end torque and at loads over 70 percent instead of it going rich it will run lambda all the way through the rpm. I have seen this on the dyno with a GD3. The new GE8 will have better fuel control because of the MAF instead of the MAP. So you will get both more power and mpg. Adding a partial tank will not advance the total timing because the knock sensor wont allow it. It will slowly add timing and when the o2 sense a rich mixture it will lean it out by modifying the injector pulse. The better running engine with an auto trans will make the shift firmer and faster at a lower rpm reducing the stress on the trans. and engine. Engine and intake temps and Barometric pressure with timing and fuel control is constantly changing and modifies the original map which is stored in Random Access Memory(RAM) which removing the battery terminal removes and has to rebuild.

 

With the increase in low end torque from 93 octane you can pull hills at lower revs, using less throttle and a taller gear in a lot of situations and get better fuel mileage while doing it that way...

 

I have no reason to worry about damage to the anti pollution system at this point in ownership... Sometimes you have to work around things like that if you like to drive a fast car.....I'll tell you what, Ill announce my glaring stupidity, lack of knowledge and lack of good judgement if and when there is a problem and the warranty is void because I fill my tank and the filler tube....My most glaring display of stupidity and bad judgement was when I put myself in a situation where I wore an Eagle Globe and Anchor for awhile.. That was when I was in the company of all kinds of idiots and fools.

 

For these reasons I think I might be using premium for my winter fuel of choice. I've noticed a drop in the low end torque over the past few months and I'm thinking the winter blend simply takes it out of the engine.

In the summer I really wasn't feeling the loss and this winter has been in the top three warmest in 112yrs around here and I'm seeing that on a few local hills I'm needing to drop to fourth where I've always been able to take them at 35mph in fifth. Taking them faster isn't an option - residential country road w/ lots of families.

 

I really must thank Coyote, SB, and DSM for alerting us to the Japanese car and Big Oil conspiracy.

These two entities (Cars and Oil) have concealed for decades the fact that economy cars will perform better and get better mileage using high octane fuel.

Big oil benefits through increased sales (lower MPG results in more fuel sold). The car companies have no excuse, they're probably just backing up big oil.

Without Coyote, SB and their large son (where is that boy?) we'd be unaware and stuck with our under-performing, low MPG economy cars.

Please join me in saluting these Fitters! (especially SB, he doesn't even own one. Such dedication!).

 

I run it on 85 octane (Utah's lousy fuel). I run it on 87 when I'm in Los Angeles. I get comparable gas mileage using either. No difference.

Tracking with Fuelly and it backs me up. Very low 30s with lots of city driving. Upper 30s on highway.

 

85 octane at elevation is supposed to be equivalent to 87 at sea level.

 

I ran 4-5 tanks of 93 and saw no economy difference. in fact, the highest economy i ever got (multiple tanks of 40mpg+ in a row) was using regular old 87. My lifetime average at this point is around 37mpg but that is going to drop with my new commute to work. Last few months have been 30-32mpg.

~SB

 

i just filled my third tank. i tried to top it out lol but i got scared that it wouldve over filled :X

anyways i refilled with 87 this time around, so far i felt that i've gotten better mpg (or maybe its cuz the way ive been driving) not sure. but so far i felt no difference in performance or anything else. im currently getting 37 mpg though.

 

just use the recommended fuel. you're not running a turbo or anything high performance so the rich fuel is just gonna be wasted, so you'll just be wasting your money. that's my 2 cents though.