Awful city MPG, awesome highway MPG

[JingChuan]

Ok, I know that 4 tankfuls do not make a very effective sampling. So take this with a grain of salt: we filled up the tank before road tripping down to Indiana this weekend. The last tank was all city driving, cold starts, short trips...16.79 mpg! (boom01)

We filled up there, after all highway driving, 60-65 mph the whole way... 32mpg.



(Side note, we had to fill up in the city since she let the tank run down to below E (hand); I've lived in Chicago for 8 years and this is my second fill up in the city limits. $4.47/gal for 87 octane! We filled up in Indiana before leaving ($3.98/gal - geez, 50 cents a gal difference! 50 cents!!! Really? In less than 60 miles?)

 

[Orangutan]

How is that awful? That's almost 17 on a car rated by the EPA for 21 city, which is very little like actual city driving. Consumer Reports' testing earned 15 mpg city and 34 mpg highway, 23 mpg overall, and 29 mpg on a 150 mile highway trip. That falls in line with similarly sized, weighted, and powered vehicles. If you look at the actual window sticker on the car, too, you'll see that the rating of 21 is midpack in what most consumers can expect to achieve, with both higher and lower city ratings normal. I wouldn't worry about it. I'm impressed you hit 32 on the highway, though. I've only done that once or twice and despite conservative driving can't reliably hit 30.

 

[chandlerGTi]

That sounds about right, my best single tank average is 30.8.

 

[DKaz]

ANY vehicles subject to cold starts and short trips will get VERY POOR mileage, unless you have a fully electric vehicle, then these things shine in cold start-short trip conditions. Hybrids will perform just as poorly unless you have a fully charged battery and put it in EV mode, and while diesels normally shine, they need more time to warm up and will do just as bad.

I can normally do about 9.5-10L/100km (23-25MPG) on city trips longer than 5km, and the last two morning commutes I did 8.7L/100km (27 MPG), although in the afternoon I bump up to 11-12L/100km (20-21 MPG) because of traffic.

 

[JingChuan]

So take this with a grain of salt

Hypermiler wisdom aside, just common sense would dictate that typical city driving returns lower mpg than highway. We know how a cold car runs rich, and basic physics about a body at rest, etc. Nevertheless, 16.79 is still low for a 21 mpg city rating. While I fully expect that city number to go up as the car (well, the ecu anyway) breaks in, I'm still going to report what I've seen. If my highway mpg goes up too, I'll be ecstatic, although just maintaining 32mpg highway would be quite nice. I've hypermiled cars before, and I averaged 36% better than EPA in my particularly thirsty Mazdaspeed3. Even our turbo Jetta averaged 26 in mostly city. We know mpg wasn't Mazda's strong suit, well not until Skyactiv anyway. Man, I wish they would have put that engine in the 5 for 2012! I certainly hope 16.79 is not indicative of city mpg for our 2.5.

 

[torquelover]

My wife drives her MZ5 with a heavy foot, and she's averaging 25 MPG overall so far. We were in the city yesterday so I reset the avg econ once there and we still registered 19 MPG with all stop and go, four aboard, A/C on and ludicrously long idle time stuck on LSD waiting to get to the parking lot (something went wrong, lot attendants were doing cash only, lots of rage and people pissed off!). How many miles on your MZ5? What PSI in those Nittos?

As a side note, I have only seen one other MZ5 until yesterday's trip. Now the kids play a variation of the slug bug game only with the MZ5 there were so many downtown. "High Five Mazda 5" is what they call it. They were all Sport models so maybe they were rentals?

 

[thaxman]

A couple of things: it will take a good 4 miles 1-way to compensate for a cold engine's pathetic fuel consumption. I drive <2 mi & we lose 3-4 mpg vs. if I had to take a longer trip (all city) ex. I was selling my CRX & I would drive it 1/4 mi to park it outside the hs w/a 4-sale sign, then drive it to another local site for the afternoon rush before I would take it home in the eve. I got something like 14 mpg after a few weeks. It was HALF what it could get when I would commute with it (And I used to drive it like I stole it)
2nd: The AT DOES have a lockup torque converter, but in city driving, it usually doesn't get to lock up very much, which means that the torque converter is nearly constantly slipping to some extent as you accelerate & change speeds in normal city driving. My 2.2L VTEC Accord never even got 20 mpg and the 2.2L Subaru usually got 18 mpg because they were both AT. My Mz5 MT gets 23-24 city, which blows away EPA mpgs for 06. I bet both the MS3 and the Jetta TDI are both MT, which absolutely explains how you can better EPA mpgs city. I have NEVER done as good as EPA city mpgs in any AT I have ever had.

 

[JazzLix]

We have been driving almost 100% city sonce we bought our 2012 5 in April. Finally got it out for a road trip. Approx 1000km round trip (all done on cruise @ 110km/h; included approx 80km of city driving in and around Ottawa), recorded 7.9L/100km vs. almost 11L/100km city. Not bad for a van, but obviously nowhere near the mfg posted expectations. Someone at work told me all mfg specs as far as L/100km ar based on hwy driving @ 90km/h?

 

[Formulanone]

In mostly city driving, we were averaging about 18-19 mpg; after the first oil change at 5000 miles, the fuel economy increased gradually to its current 22-23 under the same conditions. We averaged an exact 25.0 over 2000 miles of almost-entirely highway driving during our winter road trip...not bad with a family of four and a vehicle packed (everything fit perfectly with no visible obstructions!) with ten days of stuff plus Xmas gifts.

I can't help but wonder if some sort of upgrade/bulletin occurred at 5000 miles, because the sudden increase in fuel economy was rather mysterious to be linked to just a change of oil and filter. Sure wasn't anything else listed on the repair order...

 

[fitzski]

Updated the numbers for our Mz5... very happy so far. A recent family road trip - loaded up including the roof-rack-mounted cargo box - netted a respectable 26mpg (9L/100km).