Mileage reports: Automatic transmission (5AT)

[Super Mario]

Originally Posted by Tomwaits

I'm filling up at the Old Town Arco typically. Most of my driving is on the 5, though I'm only 3.5 miles from work now, so the car never really heats up and mileage suffers. Still, tank after tank around town, it's 31 to 33. I also drive as smoothly as possible, limiting braking and acceleration as much as possible. No jack rabbit starts and try to anticipate traffic as much as I can. That seems to help quite a bit and after a number of drives to northern cal and Mammoth, the difference between 70 and 80 mph seemed minor.

Tom, what color is your car? I live in Clairemont, but I always drive down to Sports Arena Area to get food like 2-3 times a week, so I might just run into you on the 5 or the 8. I'll try to look for ya. I'm an Asian dude in a Silver Sport.

[AtticusFit]

ok so heres what i got 08 fit sport AT got just at 1000 miles on it and started my little gas test.
last week filled up with mid grade 9.332 gals got 247.1 which comes to 26.47mpg not good
filled up this morning with reg. grade 9.541 gals
my wife drives so never sees sport mode or vtec and drives city drive arounf town and drop kids off at school.
the mpg doesnt sound right any suggestions???

[manxman]

Originally Posted by AtticusFit

ok so heres what i got 08 fit sport AT got just at 1000 miles on it and started my little gas test.
last week filled up with mid grade 9.332 gals got 247.1 which comes to 26.47mpg not good
filled up this morning with reg. grade 9.541 gals
my wife drives so never sees sport mode or vtec and drives city drive arounf town and drop kids off at school.
the mpg doesnt sound right any suggestions???

There are some amazing differences in the extremes of mileage reports in this thread, and this fact keeps being repeated. It seems to me that if the extremely LOW mileage reports are accurate, there must be a defect that should be a warranty issue.

I just got back yesterday from a trip from the San Jose, CA area (approx. sea level elevation) to Carson City, Nevada. Filled up at the Costco gas station in Santa Cruz, and force fed the tank with repeated top offs. Then drove 308 miles over the Sierra Nevada mountain range (7000 feet high), through Lake Tahoe, and ended at the Costco gas station in Carson City, NV. Force fed the tank again, and it took exactly 8 gallons. That is 38.5 mpg, going 80 mph whenever possible (due to slow traffic in the way), A/C ON, over 7000 ft. high mountains.

At only a little over 8000 miles on the odo., I guess the engine is still "breaking in", and I punish it in all long drives. Trans. is AT, and my mods are 1. coolant bypass on the throttle body, 2. low restriction short ram intake, 3. low restriction exhaust, and I have used Amsoil 0W20 Wt. Synthetic oil after the first 5K miles.

So, some of us get fuel economy that backs up the advertising, and apparently many of our members do not. With exactly the same specs. and drive trains, and my own driving technique being the opposite of "Grandma", I tend to believe that there is a mechanical cause for the low mileage claims.

[Wuze]

At what RPM do you guys shift with paddle shifters? My Fit only has like 150 miles on it, but I'm still only getting like 20MPG. Originally I was driving it around in D, but lately I've been driving in S for fun.

[TOOL]

Just filled her up today, and i got 32mpg ALL city driving!!!
Best ive gotten in a while.

Tyler

[Wuze]

Originally Posted by Wuze

At what RPM do you guys shift with paddle shifters? My Fit only has like 150 miles on it, but I'm still only getting like 20MPG. Originally I was driving it around in D, but lately I've been driving in S for fun.

Question still stands.

Also you can shift from D to S and S to D while driving and whenever, right?

[manxman]

Originally Posted by Wuze

Question still stands.

Also you can shift from D to S and S to D while driving and whenever, right?

Try to shift below 3500 rpm. The answer to your second question is RIGHT.

[henryd1981]

Originally Posted by AtticusFit

ok so heres what i got 08 fit sport AT got just at 1000 miles on it and started my little gas test.
last week filled up with mid grade 9.332 gals got 247.1 which comes to 26.47mpg not good
filled up this morning with reg. grade 9.541 gals
my wife drives so never sees sport mode or vtec and drives city drive arounf town and drop kids off at school.
the mpg doesnt sound right any suggestions???

You will eventually see a steady improvement the more miles you put on. I'm closing in on 3000 miles, and I'm currently getting around 27-28 mpg, with some freeway driving and a lead foot. I was seeing similar mileage of yours when I was at around 1000 miles.

Don't worry, it'll get better!

Here's a visualization of my gas mileage: Car "breaking in" and Eco

[MINI-Fit]

Originally Posted by henryd1981

You will eventually see a steady improvement the more miles you put on. I'm closing in on 3000 miles, and I'm currently getting around 27-28 mpg, with some freeway driving and a lead foot. I was seeing similar mileage of yours when I was at around 1000 miles.

Don't worry, it'll get better!

Here's a visualization of my gas mileage: Car "breaking in" and Eco

2008 Fit Sport AT
2500 miles and mpg is still stuck at 26 mpg except for one time when I got about 31-32 mpg by driving at under 2000 rpm nearly all highway at 55 mph or less.

Speed limit in my area is 50-55 tops. No 70 or 80.
Mixed driving usually 25 to 26 mpg. Easy on the throttle and no changing with more miles so far.
87 octane top tier gas. Same gas no trouble getting 30 mpg with 2006 Civic EX 4 dr sedan using same drivers on same roads.

You can use paddle shifters from 2000-2400 rpm. You can move from D to S and back again on the fly. For best and low rpm shift early with even easy throttle. For best acceleration shift later 3500+ rpm.

[xorbe]

drive like a 6500 rpm madman for a tank or two. loosen that motor up!

[xorbe]

btw, over in the KW supercharger thread, Oscar said that our L15A is a longer stroke compared to other Honda 1.5L motors.

Longer stroke means more working torque and less mpg, right?

[mahout]

Originally Posted by shipwrek

i got 450kms out 36 liters in almost total stop and go (traffic, lights, etc.) with an auto LX

28.64 mpg.
0.621 mi per km and 3.785 liters per gal

[BONES76]

Usually when my hits the 1/2 way mark I fill up....then divide the miles by the gallons on the pump. The 1st tank sucked major...was 26 mpg...after the 500mile mark it started getting better...now with 1200 miles been avg 33-35 mpg. Which imo is great for a auto tranny...Happy? YES SIR...and for all those manual folks the auto is just as fun and has more play modes...na na ..lol.

[i like guitars]

i average about 30-32 in stop and go traffic. i drive during peak hours here in orange county and i wish i could get more but i think my old civic averaged 25, so im good. i got an automatic by the way.

[kusojiji]

Originally Posted by xorbe

btw, over in the KW supercharger thread, Oscar said that our L15A is a longer stroke compared to other Honda 1.5L motors.

Longer stroke means more working torque and less mpg, right?

The L15 has a 89.4mm stroke. As compared to the other Honda engines of similar size, the engine that comes the closest is the B20 at 89mm. I was surprised to see this long of a stroke in such a small engine.

Longer stroke is supposed to create more torque down low and increase mpg since rpms remain low as compared to a short stroke engine needing to turn rpms to make power. More rpms, more air, more gas. Again, this is all "supposed" to happen.

[xorbe]

But, the longer cylinder stroke also means more internal engine friction per revolution? A square 1.5L (78.159mm) has 191.92 surface compared to the motor's actual 205.48, according to my quickie spreadsheet. And the higher piston velocity.

a1: [bore in mm]
b1: =1500000/(pi()*A1*A1) [stroke in mm]
c1: =A1*pi()*B1/100 [surface in cm^2]
d1: = B1*pi()*A1^2/1000000 [litres]

(lol wow, 89.4mm is longer than my Z4's 87.9mm!)

[kusojiji]

Uh oh, mathematician! I'm in trouble now!!

Friction is a factor of piston ring area and the speed that the piston ring travels over the bore (and all of the other internal rubbing surfaces). The Fit has a small bore at 73mm (soda can is 65mm).

While I don't have the exact figures, long stroke engines have higher piston speeds than a short stroke engine at the same rpm. But, since the long stroker makes more torque at a lower rpm, you don't have to spin it as high as the short stroker. At the rpm that the short stroker needs to spin at, the friction may be equal. Make sense?? Took me a long time to write this!!

Also, long strokers generally make torque over a longer rpm range than a short stroke engine, which tends to be peaky. You can short shift them (Fit, yeah right!) if you had enough power to make a difference.

[airborne200208]

87 Days of fuel usage in an 08 Fit Sport Auto, 108 FT above sea level in and around Anchorage Alaska.



*edit* added more details

[kusojiji]

Those numbers look like all city. If so, that's a lot of driving around Anchorage! I know you can go 38 miles between traffic lights over there!

[airborne200208]

Yeah, I live in South Anc, drive 16 miles to Ft Rich at 5 am with almost no traffic, then 16 miles home at 5 pm with rush hour can't go nowhere traffic. I average 35ish mpg in the am and 20ish in the pm.