Break in period and fuel economy

[tech10002]

I searched for all the fuel economy threads I could find and couldn't really find an answer to this. I was curious if anyone has noticed any significant fuel economy increase after you get some miles and if so how many miles it takes.

I'm more than a little disappointed in the fuel economy on my new 2012 5 speed hatch. I realize the automatic does better, but I still expected better than 31 MPG for an almost all highway commute at speeds below 70 MPH the whole way. My 16 year old 5 speed Civic with 200,000 miles that the Focus replaced averaged 34 MPG on the same commute, and the city/highway ratings of the Civic were lower than the Focus.

I'm hoping it will get better with time. I've got a little over 1k on it now.

[darkangelism]

What MPG are you getting? You might see some increase over time but probably not more than 1mpg.

[kam327]

My quick analysis of fuelly.com user data a while back showed most folks generally do not see huge increases in mileage after break in. Maybe within the 1st 1 or 2 tanks, but not after that.

Do a test: get to where you can maintain a certain speed for a good 10 minutes, reset one of your mpg readouts, and see what mpg you get. Should roughly match the curve below which I also did and which roughly agrees with one done by one of the car magazines a while back. If it doesn't maybe you have a mechanical problem. If it does you may be underestimating your lead foot or something. Although your comparison to your previous car suggests it's not you.

[tech10002]

First tank on the all interstate 240 mile drive home from the dealer was 32.68 hand calculated, 32.4 on the trip computer. The second and third tanks which were all 55 MPH back road and interstate commute to work with very little city driving were 31.5 and 31.2 hand calculated with the trip computer reading pretty close each time. I just didn't write the readings down. Almost all interstate driving is with the cruise set at 68 MPH.

All of those are with one occupant and no cargo windows up A/C on with temps ranging from high 50s to mid 80s.

[darkangelism]

Those are not horrible mpgs, probably about average, AC is probably costing you a bit, but I wouldn't expect more than a mpg or 2 better without doing some mods or switching to 93 octane gas.

[Elizabeth]

MPGs.. More questions about MPGs than anything else IMO.
Seems to be some folks get horrible MPGs, the some get great MPGs.
I m in the great camp, with an average of 35 mpg with 70% city driving.
That is city with few stoplights and no traffic congestion.
Add in a LOT of stops at lights, and plenty of congestion, and my MPGs would drop like a STONE. (30mpg)
So that is my opinion on it.
Every stop and moving back up to speed kills fuel mileage. A LOT of stops, or even hills, and you have bad MPGs.

[GoldenHour]

Originally Posted by Elizabeth

MPGs.. More questions about MPGs than anything else IMO.
Seems to be some folks get horrible MPGs, the some get great MPGs.
I m in the great camp, with an average of 35 mpg with 70% city driving.
That is city with few stoplights and no traffic congestion.
Add in a LOT of stops at lights, and plenty of congestion, and my MPGs would drop like a STONE. (30mpg)
So that is my opinion on it.
Every stop and moving back up to speed kills fuel mileage. A LOT of stops, or even hills, and you have bad MPGs.

that's right. stop and start + heavy foot will eat you up. in town only i get maybe 22 mpg. i just drove home from monterey and took it easier than i normally drive. i averaged 37.2 mpg for the 70-mile drive.

at over 1500 miles i'm averaging 24.5 or so. i'm cool with that. that's double what i get in my tundra.

[gambit293]

Originally Posted by Elizabeth

I m in the great camp, with an average of 35 mpg with 70% city driving.
That is city with few stoplights and no traffic congestion.
Add in a LOT of stops at lights, and plenty of congestion, and my MPGs would drop like a STONE. (30mpg)

That is FABULOUS gas mileage for 70% city driving. I have a fair number of stop lights in my daily drive (and a lot of slow/clueless drivers around me), and I'm very lucky to attain an average of 25 mpg. I've only had the car a bit over a month so far, so we'll see.

The presence of lousy drivers and lots of lights makes it very difficult. I am VERY conscious of stop light signals. I'll drift up to reds and intersections that I clearly will not get through in time. But I get stuck behind drivers who obliviously drive very slowly to intersections that we could all clear but won't because the driver won't speed up a tad. So we end up stuck at the red. Or worse, slow driver barely clears and everyone behind him gets stuck. And sitting at stop lights absolutely massacres MPG. Consequently and ironically, this makes me a more aggressive driver, which of course hurts mileage. I also fight to get past and around large cars with poor accelaration as they will inevitably mess up my timing.

[revhigh]

Originally Posted by gambit293

That is FABULOUS gas mileage for 70% city driving.

It may be IN a city ... but it's more like RURAL driving than city driving .... at least as it was explained.

City driving is considered like it would be in NYC ... lots of lights (every block usually) ... lots of iding .... and very low speeds ... at least that's what I consider city driving.


REV

[TboneZX3]

Originally Posted by revhigh

It may be IN a city ... but it's more like RURAL driving than city driving .... at least as it was explained.

City driving is considered like it would be in NYC ... lots of lights (every block usually) ... lots of iding .... and very low speeds ... at least that's what I consider city driving.


REV

Yeah, it seems there's a very wide variation in what people consider "city" driving. My "city" driving wouldn't be close to what others experience in urban areas. Mine should probably be described as "rural" or "Bum" driving.