I went to a Exxon gas station yestrerday to fill gas for my Civic Si. I noticed that there is a sign "contain Ethanol" above regular gas. Will it save to fill regular gasoline with etharnol to our FIT?

 

The gas/ethanol at the pump will not harm your Fit, if that's the concern.

 

Yes, since there is no where in Honda Owner Manual mention it (as far I read and search the keyword).

 

Mobil went top tier in July of this year. Your SI needs premium and your Fit can use what ever you want. I always used premium in all my cars but thought I would try regular and now mileage is way up and except a little serge when accelerating it runs OK. Because of the high humidity its running good on regular and the ecu has not tuned back the car yet. The high humidity is like running your car on water injection. The water vapor cools you engine. Just wait until Oct. when(if) the government OKs 15 percent ethanol.

 

Do you mind explaining the "surge" you mentioned? I'm only at 700 miles and I've only filled twice. The first tank I filled was premium. The latest was regular and now I notice in 2nd and 3rd gear around 3k rpm the car will act like I've floored the pedal a bit.

 

Its a lean surge and will go away. It the ecu hunting for the right parameters.
What Causes Surging in Car Engines? | eHow.com

Just use a top tier gas at a station that sells a lot so the gas is fresh. My car is now running better.

 

Honda's have a lean burn characteristics by design. Here is a good explanation of a lean burn engine Lean burn engine for automobile - US Patent 5765372 Full Text

 

I am getting avg 35 mpg 50/50 city/hwy. In 90% hwy, getting 43 mpg.

No difference when I used either 87 or 91 octane, power or fuel economy.

The Fit runs happily on 87 octane.

If I feel the engine needs some injector and valve cleaning, I will simply add a bottle of a good fuel system cleaner like Chevron techron plus. Otherwise, no need for V-power or 91 Chevron premium fuels. I usually feed the Fit with 76 or chevron regular, so far, it has been fine.

 

If you tend to drive at higher speeds, into head winds, with passengers on board, or when the ambient temperatures are very high, you will have more ignition advance and produce better fuel mileage figures under those conditions with premium fuel.

 

Good mileage. Many many Fits run beautifully on 87 octane [mine included].

MPG improvement w/ premium fuel is mostly imaginary, however, I do trust in those who do see improvements. There's been lots of discussion.

When I saw the Shell boost my MPG was in my 96Deville. That engine benefited from the high detergents in the fuel improving air intake characteristics I'm sure. W/ the Fit I doubt I would notice.

 

The higher than normal temperatures that seems to be occurring all over the country right now would seem to be causing the knock sensor ignition retard system to be working over time this summer.... I monitor ignition timing on my ScanGauge and I am seeing ignition timing advance staying in the lower to mid 30s where before it got so hot it was in the upper 30s and low to mid 40 degrees of advance even with octane booster.... I am seeing a 10% drop in fuel mileage right now and in addition to the heat the A/C is causing a lot of the drop.... Premium fuel without booster is doing as well as premium with booster but I am driving like a little old lady as much as I can stand doing so.... With just a short ram intake and a free flowing axle back pipe I was getting 37 to 39 MPG driving fast all of the time... I had a resistor device that kept my car in open loop mode and richened the A/F ratio allowing the timing to advance more than it would have otherwise.

 

I've been watching the timing advance. The range is surprising. Been wondering if the effect of premium would effect it. Thing is it's all over the place while driving so I'm not quite getting it.

 

There 2 types of cars we are you are talking about. the old Fits are and vtec whick runs 3 valve until 3500 rpms and then the forth valve opens. The new itvec Fits has the same vtec but also changes cam timing for more efficient power and mileage. Also the ivtec uses the maf sensor to time every cylinder for better fuel delivery. Premium gas allows better control of temperature on pistons with knocking and has higher energy hydrocarbons so better mileage can be achieved. Regular works OK but you dont know for how long and the extra carbon deposits just worsen the problems over time. If your car knocks the ecu counts the knock and eventually retards the timing and stores it in long term memory so your car runs less efficient poorer mileage, lower power, and eventually engine parts failures including emission parts.

 

What RPM range do you believe is the optimal one for best fuel economy?

2010 Taffetta White
Sport, 5 spd

 

You guys got me think'n so I started a thread on "Where are we headed as a nation". It would be good to see your thoughts on this topic. This is started to see and understand where we as adults see the country's future.

 

The rich get fat and so do the poor now that they are eating GM food laced with hormones and HFCS.... We owe our changing lifestyle to the Federal Reserve, international bankers and corporate gluttony.... Impose the death sentence on special interest lobbyist and the elected officials they own and the process of improving the rights of citizens will be underway.. My next post will be on topic, I promise.

 

The first gen Fits anything below 3500 rpm gave me the best mileage. I had a 2008 Honda Fit sport w/mt and the best was 47mpg on SG but had to pulse and glide and drive slower around 60mph. The new fits are more forgiving because the cam timing will run it in the best position for the best efficiency. I get up to speed around 61 mph and let off the pedal and slowly push down and the cam advances and mileage goes up to 60+ mpg on SG. I would think its based on the way you drive because the car tunes itself as you drive. There are a million variables so its it depends. When I drive faster I still get mpg in the 50s not to bad for a autotrans.

 

I see that today is better than tomorrow. I think things are going to get alot worse very fast. It doesn't matter how much money people have because there is no industrial to back it up. I see it every day. It all service jobs and when people wake up and realize they dont need it and can do it for themselves, and then realize whats important before its too late. Money valve is based on what produced and not what a service job can do for you.

 

hmmm... I think any increase in fuel economy with premium gas is really "placebo" effect. If using 91 octane gas makes it better, the car manufacturer would have indicated as recommended octane.

I do believe in using only top-tier gas, not because it gives better mileage, but just for the much better and higher levels of detergents, keeping the car running like new.

There is only so much energy that can be released from the combustion process, breaking of carbon bonds...

 

Premium gas has the same low boiling point as regular, but has a condenser middle to end boiling point. It has a lower end point too. Fuel must vaporize to burn so the advantage is that the middle boiling points vaporize and cools the pistons to give a denser charge with full advance of timing with out knock. There is more energy in premium gas, even if it 3-4 percent the ecu takes advantage of it. It all depends on driving style and conditions. If you alway run regular your car will detune and mileage will drop. Do you remember when leaded fuel disappeared and you would richen up the carbs and take a few degrees of timing out so you can use lower octane fuel. As the Honda burns fuel it builds up carbon to a point which equalizes at 15000 miles, the engine compression is raised and the car detunes it self. Ive seen a total timing of 50 degree plus when when new. It only goes to to 40 now even with regular. Premium burns faster because it vaporised faster, if it burns slower there is more time for knock.