Knock control tables good reading

 

Thanks DSM, time to do some reading.

I'd love to see some data like Selden's to prove the opposite as at this point, with the few tanks I've put in, I've seeing absolutely no benefit to Premium. I think I'm also on the higher end of most people here as far as lifetime fuel economy is concerned with 38+mpg over 20K miles.

To me, the fit seems like it was designed to run on 87 unlike my altima, which Could run on 87. Differences being the fit seems to be optimized for 87 while the altima was optimized for 91+.

~SB

 

Now you are flat out changing the facts to fit your narrative. My own data:

Regular Gas: 39.63 avg mpg Atl-DE, 755 miles
Premium gas: 36.68 avg mpg DE-Atl, 747 miles

The BEST of the four fills with premium was still lower mpg than the worst of the 3 fills with regular, so I have no idea where you are getting your imaginary consumption figures.

I have seen anecdotal reports on these forums of people who get better mileage, worse mileage, and no significant difference with premium. Most of these reports lack supporting controls. The best documented report that I remember was a trip up and down the west coast, which reported less than 0.5 mpg difference. I did this experiment to test the hypothesis that premium gasoline delivers better gas mileage than regular. My data suggest not, but they are not conclusive; without more/better data, this discussion will remain mired in opinion and anecdote -- which is the norm for this place, and among the reasons I dropped out for several months.

For the record, DSM, if you are concerned about appropriate content, this thread is in the "2nd Generation GE8 Specific ECO-Fit Discussion Sub-Forum Threads discussing the pursuit of ultimate economy, hypermiling techniques & maximizing your MPG for the 2nd generation GE8 Honda Fit". Discussions of other measures of performance and other vehicles belong elsewhere.

 

For the record this is what you said, I didn't make anything up. That is your post right there, and what I am discussing is pertinent to fuel economy.

 

Time to check back in now that I've completed around 6k miles driving down to both coasts of Florida and the up to Caribou Maine twice in the past five weeks.

This AM I'm seeing 16,284miles on the ODO and oil life is at 50%. Just after my quoted drive above I had the first oil change and the tires rotated, then began my latest odyssey.
>>>>>>>>>>>>>>>>>
Here's what I've observed/experienced regarding fuel economy and my 2010 MT FIT, 34psi all around, regular fuel from high volume stations when ever possible:

First thing is that over 1300 miles driving from NY to FL I've seen better turnpike mpg's on the northern half than on the southern half. I followed I-95 and drove at 70mph w/ cruise and was seeing 37-38mpg on the northern leg and 35-36mpg on the southern leg. I'll use Chesapeake, VA as the half way point 'cause that's where I tied up w/ Perrenoud for a great BBQ lunch on the way south.

Once in Florida I stayed 10 days on the west coast in the Coco Beach area and saw the mpg's shrink to 34-35 under local driving conditions. This was w/ three in the car and stop and go urban sprawl driving. I could get similar results driving in Manhattan, and in Florida I am driving on a pool table w/ stop lights every 1/4mile.

I then headed across Florida to the west coast and saw the mpg's climb a bit to 36. I was in Bradenton, 25miles south of Tampa. Another week and a half or so there saw the mpg's at 36-37.

I saw similar numbers on the 1300 mile return leg as I saw driving south, though I did by-pass Mike heading north, sorry buddie - but I did the return drive w/ only one night on the road, had to get home for my annual.

So back in upstate NY I'm seeing 38-40mpg again and I start my trip to northern Maine. The Mass Pike gives me those 38-40mpg numbers 70mph w/ cruise on and driving local and coastal roads I see 40+. I did two trips up to Maine and saw similar numbers both times.

All tolled, if you're following, I've driven up to Maine at least five times since I've had my FIT and short of my first trip - FIT was brand new - I've seen those 38-40mpg numbers.

So, I conclude my FIT gives better mpg in the northen half of the east coast than the southern. Now, not wanting to open another can of worms, I believe it's got something to do with the topography of my driving. Those up and down hills tend to give a better return than straight flatland driving.

Regarding this thread, I'm not surprised to see the regular/premium guys trying to make their case. That debate will NEVER be resolved. To each their own, but given the vast amount of variables in everyday driving and the fact that mpg's are based on averages all around it is those averages I, as a conscientious consumer, am interested in and regular fuel is less expensive than premium.

For kicks I have tried to see in premium gives better performance, and to be truthful I can not see any difference at all. I does, however, do my heart good to pull into a Shell station and fill-er-up w/ their high test every once in a while. On the open highway it's not uncommon to get fuel where ever you can when you need it and regular fuel in the Honda Fit works great.

As far as comfort - I've raised the front of the seat rails a bit and after 6k miles I've experienced no physical discomforts.

This car ranks high in my book, happy to own it.

 

I really wish the weather wasn't cold right now because I'd love to go back home and back with a tanks of premium in my car with the weather being about 65-80 degrees. The one thing different about my car is the fact that I have a K&N TYPHOON INTAKE! I just wanna remind everyone about that, also, I've got LARGER TIRES AND WHEELS TOO! Now, when the weather was warmer, going back home to Detroit and back to Chicago I got 39 mpg coming in and IIRC 41.3 mpg coming in. Now, I have no way of measuring wind, all I can say is that I do drive the same way everytime, right lane, cruise on 70 mph. With the air being more dense when its cold like it is now though, my intake probably works against my mileage numbers due to how well my intake works on the perf side, it does make 4.53 whp, so its doing something. Plus, my tires are 20mm wider and my wheels are 1" wider too, a bit more weight and wind resistance with the wider tires. My over height is the same though, so the final drive ratio hasn't been changed one bit.

My experiment with BP starts on my next fill up, although it will take a couple tanks though, I usually fill up when its between half and quarter tank, I've never run tank low in the winter time, no way in hell! We can all agree that that's never a good idea

 

Perhaps you are dyslexic? If you will take the time to read what you have quoted, you will see that I reported a calculated 39.63 mpg not 36.9 mpg. 39.63 - 37.1 = 2.53.

SilverBullet has raised a valid point, that winds along this route are generally from the south, even though it was relatively calm on both legs last week. Since I make this trip once or twice a year, I will have another opportunity in the spring, when I will start filling the tank with premium several tanks before the trip, and I will record results in the opposite direction. In the meantime, I would love to see detailed reports from others, as opposed to anecdotes.

 

Did you dyno your Fit before/after the Typhoon intake change? Was this the only mod? If so, that's useful data. I am skeptical of results published by K&N.

When the OEM tires wear out (currently looking pretty good at 20,000 miles), I plan to replace them with the same size as you (205/50); mileage may suffer a little, but handling and ride should improve.

 

Looks like you are right, however I am not actually dyslexic but close, when I was younger I had issues with discalculia (brain inverts numerical digits), which I still do occasionally it appears, my apologies.

I will follow up if I have a chance at lunch.

There is alot that goes into determining mileage, there are discreet differences between grades and more obvious differences between individual stations, as well as from brand to brand. Some station owners will buffer their tanks and bottom lines by using 2-3% water in their storage tanks. More often this happens by accident, but it is one of many factors to account for.

Because of this it helps to run out almost empty on each tank, filling up at 3/4 or 1/2 tank can skew things significantly.

 

I suspect I am also discalculic, and problems with math were a big factor in my decision to get out of engineering while in college. "A" student in logic and chemistry; "D" student in calculus.

 

I've never dyno'd the Fit, so I'm taking K&N at their word. Why don't you trust them? When looking at the Fit's stock airbox, its easy to believe you'd pick up 4 hp and FWIW, the "butt dyno" feels pretty good as well. I have a Magnaflow muffler as well, but a muffler alone isn't going to do anything but sound good and in my cars case, it does

As far as handling and ride go, my tire/wheel set up does just that and while out on the Dragon the Fit was rock solid, although the lack of hp and tq don't hurt either. I was able to push the car very hard and when I wanted to do, just to do it, make the car slide the front wheels, but again, I did it just to do it and show my step Dad how easy it was to reach the cars limits. Funny talking about limits and mpg in the same thread

 

I try to maintain a healthy skepticism regarding all advertising claims, especially for companies like K&N that market automotive accessories.

 

In the spring, the winds totally reverse... except on the 4th Thursday of the month.

JK... I'm interested in the results as I've seen no benefit to premium... however I've not seen any lower fuel economy.

~SB

 

Its 45 degrees and raining and I still managed 44 mpg with lights, wipers and part time use of defroster. I averaged 50 mph for .7 hours. I was on the highway a little more because I had to visit someone in the hospital. I noticed that the defroster used double the gas at idle and the timing was different. I found these links on corrections the ecu does based on temps. Fuel parameters

on loads Ignition parameters
throttle close injectors off Throttle parameters

My engine is 20 percent bigger than yours but has similar ecu with the same sensors so the tune is 20 percent different to compensate for a smaller motor.

I use BP and wont use any thing else now. Shell almost recked my engine but runs great now.

This is why it take a few tanks for the ecu to adjust. Tech - Closed Loop

 

Discalculia was more of a problem for me when I was in grammar school and became manageable as I got older.

Though it would occasionally raise its ugly head I did get through 3 levels of calculus, 2 semesters of physics and some statics/dynamics engineering courses.

Well for folks who drive very conservatively, the cost/benefit can come out even about even in some cases. Which I mentioned on pg 2 after my initial brainfart

In the end as long as you run nothing less than 87, like I said earlier, there will be no adverse effects or especially noticeable downsides, unless you drive, or suffer a commute that would allow you to take advantage of premium.

Were our L15As 9.5:1CR or lower I wouldn't bother to run premium unless I was:

Seeing persistent knock retard
Boosted
Or spraying.

Again, IMHO, a couple bucks extra on a 10gal tank I fill once a week is about $100-150/year, I figure the car cost me $17k, and look at that $150 (worst case) as another insurance policy and an investment in longevity. Especially since the long block in the car, or the one I am possibly picking up from WI this week will be getting some serious boost abuse in the next 6 months.

The same reasons I recommend people use severe duty service schedules for their daily drivers: because most are not as OCD as some of us in here, and they don't let their cars warm up, idle down or perform proper routine inspections or maintenance.

According to some statistic a news reporter pulled out of her cute little ass this morning, americans are keeping cars on average for 9 years now. Even extrapolated over 9 years the extra money in maintainence and fuel is worth it, to me anyways.

 

I will say my best mileage, coming back to Chicago, was achieved with the stock tires/wheels, during the spring/summer time going 70 mph w/o the a/c on, I was using 87 octane fuel too. I did get 41.3 mpg going back to Chicago one time with the larger tires/wheels while using 87 octane, so in the spring we'll see how it goes. The mileage was always better going to Chicago then going to Detroit, I wonder why that is (I bet one of you guys will know the answer)

 

We have RFG gas and Detroit has conventional gas

 

What's the difference again, in layman's terms, please! BTW, you guys wanna see fuel economy getting a beating, check out my vid in 2nd gen vids

 

RFG is made to burn cleaner this will explain it easier Basic Information | Reformulated Gasoline | US EPA

RFG Properties Survey Data | Reformulated Gasoline | US EPA
Many people thinks it the ethanol but its not that make is rfg. If you look it only in some of the heavily populated areas.

 

I am still getting good mpg. I might try bp regular but I already have been through this many times. My mpg drops by 10 percent in a few tanks and have starting issues and a poor running engine. I also notice the all regular smells the same but too a different degree and cant explain bp premium smells different than anything I could compare it too.