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BMW 3-Series Real World MPG



  • davidd3davidd3 Posts: 582
    For a long time the mpg feature of my BMW's on board computer was quite accurate, varying from actual mpg by no more than 0.25mpg. Now, 2.5 years later, I'm noticing it regularly indicates an mpg which is off (always too high) by 0.5mpg to 0.75mpg. This is my first car with this feature. Are these things just not too accurate or is mine off enough to have it checked out on the next visit to the service center?
  • fedlawmanfedlawman Posts: 3,118
    Maybe your tires have worn down?
  • davidd3davidd3 Posts: 582
    Maybe your tires have worn down?

    Nope, that's not it. The car is only 2.5 years old and I've been doing the winter tire/wheel package changeover thing. Neither set is worn down (though I have a cupping problem with the OEM tires and I'm going to run the winter tires longer this year, perhaps until near the end of my 3 year lease).
  • davidd3davidd3 Posts: 582
    I check mpg by hand too, on a regular basis. I was just wondering how accurate the readings from the car are. It seems that your experience has been the same as mine in that the readings from the car are a bit optimisitic.

    You certainly are getting good gas mileage for a V8. I think that BMWs have remarkable fuel efficiency for such powerful engines. I'm getting 24.5mpg overall from my 330i; that's roughly 60% highway, 40% local. I came out of a G35, which got about 22mpg with the same driving.
  • hpowdershpowders Posts: 4,300
    Sorry, but I deleted my post due to the fact this is a 3 Series mpg forum, not about the 5 Series! :blush:

    As I said before, I found the same thing as you with my 545i. The car's readout was always a bit too optimistic.
    After I found that out, I started keeping the mpg stats. by hand. I keep a pocket calculator in the glove compartment for that purpose. After the first year, I became less enthusiastic about "keeping score". From the chart I kept by hand, I averaged about 21 mpg over 9000 miles with 70% highway, 30% local errands. Pretty impressive for a powerful V-8, IMO. I'm sure the mpg would have been closer to 21.5 or so, using the car's readout.

    I guess BMW wants us to believe our mpg is better than it really is so we keep coming back for new BMW's! :)
  • nkeennkeen SE PennaPosts: 316
    Mine is indicating 27.3 mpg over the past several thousand miles, about 60/40 highway/urban with the occasional 150 mile trip.
  • kirkrkirkr Posts: 17
    On board computer has calculated 28.3 to 28.5 over 46,000 miles 90/10 highway/urban. I commute 90 miles round trip daily. Manual calculation thru the first 20K was 27.9 to 28.3.

  • erik10erik10 Posts: 4
    Our 2006 325i Convertible with automatic transmission got 29.4mpg from Sarasota to mid-MI a few weeks ago. A 2 day trip running 70-80 mph most of the way fairly frequent food and rest stops.
  • davidd3davidd3 Posts: 582
    2006 330i A/T. 33.1mpg according to on-board computer for round-trip of 250 miles, almost all highway @ mostly 70mph.
  • gtom71gtom71 Posts: 17
    I've had my 325i and it has about 55k miles on it. Just recently drove from NYC to Boston. I got 28-30mpg on both legs of the trip w/ A/C use and a fully packed car. 2 kids/ 2 adults and luggage. I averaged probably around 75 touching 90 occasionally.

    Usually I get 22-25 in the city driving between NJ, NYC and Long Island and Hwy around 27-30 depending on how spirited I drive. I've seen the computer hit 34mpg on a fresh tank and right onto the hwy, but only going about 60 on the flats. Usually can't stay like that for long.

    Looking to get a 3 series convert, after I trade in the sedan for a minivan.
  • nopcbsnopcbs Posts: 43
    2003 330i zhp 6-speed

    Suburbanish-city driving: 19 mpg

    Highway @ 65 mph on cruise: 34-35 mpg

    Both on premium; regular does not seem to make much difference.

    The city number is a little disappointing as my wife's RX330 does 17-18 mpg and it is a big lump.

    Sure hope they start doing hybrids or importing manual shift diesels.
  • I have an '07 328i, auto, non-Sport. I live in the SF Bay Area and usually sit in a bunch of traffic, so I normally only average about 21-22mpg.

    When my parents were visiting in September, they took my car down toward LA for an overnight stay. They got 36.8mpg on the way down!!! I did the math, and it's true. My dad said they filled up, got directly on the highway, set cruise at 70, and didn't hit any traffic. On the way back, they got 32mpg - I think partially because my mom drove for an hour and she didn't use cruise control.

    Last week I had to go up to Sacramento for work (105 miles each way) and averaged 33mpg, setting cruise at 75 at some points. Very happy with the fuel economy!

    Is there any particular reason why my car gets such good numbers?
  • kyfdxkyfdx Posts: 53,815
    Started driving this to work.. for the last three weeks... Suburban interstate commute of 20 miles (17 on freeway)... plus errand running outside that..

    1st tank.. 25.1
    2nd tank... 25.9

    Not bad for 235hp and 18" performance tires.. :)


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  • disco99disco99 Posts: 74
    Not bad at all..Those are incredible averages. I think you meant "17" local..correct? I hope you're not just cruising at 50 MPH on the right lane on the freeway. (haha).

    I just picked up a 330 xi(255 HP with 18's)...and my average over the first tank is 21..Great car to keep on the highway.
  • kyfdxkyfdx Posts: 53,815
    17 of the 20 miles are freeway...


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  • disco99disco99 Posts: 74
    Oops...My goof.
    Point well taken.
  • kyfdxkyfdx Posts: 53,815
    27.2 mpg... Better mileage.. not as much fun... ;)


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  • edwardsfedwardsf Posts: 190
    I have an '07 328iT, auto, non-Sport. I drive fast and love to accelerate onto freeways and in back roads but do try to coast up to urban and suburban stops.

    Town - 20 mpg.
    Highway - 75 mph - 29 mpg.
  • roadburnerroadburner Posts: 9,477
    edited October 2010
    1975 2002 Slushbox w/ Weber 32/36 carb
    City/Suburban: 20 mpg
    70-75 mph cruise: 26 mpg
    Note that the automatic is a three speed with a top gear ratio of 1:1 and it does not have a locking torque converter

    Mine: 1995 318ti Club Sport / 2014 M235i / 1999 Wrangler / 1996 Speed Triple Challenge Cup Replica Wife's: 2016 i3 REX/2004 X3 2.5i Son's: 2009 328i

  • shiposhipo Posts: 9,152
    I thought you were going to convert the 2002 to a manual transmission. Whaddya waiting for; for me to come down there and help you? :)
  • roadburnerroadburner Posts: 9,477
    I thought you were going to convert the 2002 to a manual transmission. Whaddya waiting for; for me to come down there and help you?

    The engine and transmission only have 9000 miles on them and I currently have other higher priority uses for my hobby car budget. That said, the '02 is a sweet car; I could easily see running a 1973 tii with A/C and a 5 speed conversion for a daily driver- at least as long as there is no salt on the roads...

    Mine: 1995 318ti Club Sport / 2014 M235i / 1999 Wrangler / 1996 Speed Triple Challenge Cup Replica Wife's: 2016 i3 REX/2004 X3 2.5i Son's: 2009 328i

  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 55,144
    What's really impressive is that you get good MPG with the Weber---usually, Weber conversions lead to disastrous MPG, but of course it depends on how skillfully you or the source you get them from, jets them up. Most Weber conversions I've run into are way over-jetted (for track use basically).

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  • roadburnerroadburner Posts: 9,477
    The 32/36 swap was a very popular conversion for the 2002, Bavaria, and 2800/3.0 CS Coupes. The hot Weber downdraft is the 38/38. A number of '02 guys run them, but you really need a Schrick cam to justify going that big- and then everyday driveability usually suffers. My car also has a Bosch Red coil and a Delta Mark 10B CD ignition system(remember those?), so I'm fairly sure that there's not much more fuel efficiency to be found...

    Mine: 1995 318ti Club Sport / 2014 M235i / 1999 Wrangler / 1996 Speed Triple Challenge Cup Replica Wife's: 2016 i3 REX/2004 X3 2.5i Son's: 2009 328i

  • kyfdxkyfdx Posts: 53,815
    Don't quote me..

    But, I think my '67 2000CS (with a '69 engine), had 40/40 Webers.. I was told they came off of a 911...

    They were a little boggy starting out, but the car really came on late...

    Fuel mileage? Who cares? It was 1985.... :P


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  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 55,144
    not likely...Webers from a 911 would be downdraft. Yours were probably 40 DCOE.

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  • nephronnephron Posts: 1
    Sorry folks, I have a 6 spd 2006 325xi with 58,000 miles on it and live in snow country. I would offer to you that I don't come close to some of these numbers. I will disclose that I:

    a) do mostly city driving (75% or so)
    b) reset my computer once a year
    c) keep all service current and tires inflated properly

    I am not a speed demon but I would say that I am an "enthusiastic" driver (why the hell else would you be driving a 3-series?!).

    All told for the each of the last three years, I consistently have gotten 17 mpg. With babying and paying attention to fuel economy, perhaps I can get up to 19 mpg in the city but it's absolutely a hassle. Highway is more like 23.

    If you guys really get these numbers then great. More power to you but I can say that I don't come close.
  • tturbotturbo Posts: 16
    I drive a 2009 135i with a 3.0 twin turbo and a manual 6spd.

    It's not a 3 series, but uses the same engine and drive line as the 335i.
    I know have about 24K miles on it. I average 21-22MPG and that's pretty much year round in the Chicago area. I live in the suburban area and do not go to and drive to the city regularly. My commute is about 15 miles each way and it's about 50% steady highway, usually at 70mph.

    Within a tank of gas I do drive it aggressively and will do a few fun enthusiastic drives.
    Given the power of this car and the fact that I do use that power at times, 21-22mpg is not too bad.
    Producing and using 300hp and 300lb ft of torque requires fuel.

    I check my tire pressures regularly, and I do 41psi in the rear and 39psi in the front.
    This is higher than the standard that BMW recommends for city driving. These pressures are in line with what BMW recommends for sustained high speed driving.
    I use these pressures as they work for my 135i.

    Make sure you check your air pressure regularly as it can change quite a bit from summer to winter and then back to summer. Roughly, a 10F degree results in 1psi of difference.
    So, if you last checked your tires in warm early September and it was 80F, and it's now 40F, your pressure could be at least 4psi lower than it should be. That won't trigger your tire pressure sensor, but it will result in lower mpg. Combine that with oxygenated fuel for winter use, which is in pumps now for those areas that require that fuel, and your mpg could be 10% or more lower than it was during the warm months.
  • shiposhipo Posts: 9,152
    edited November 2011
    Sorry nephron,

    Both my 328i and my 530i (5-Speed manual models) never-ever got worse than 22 miles per gallon for a single tank of fuel in New York City metro traiffic. The flip side is that both cars were easily able to return low to mid thirties on longer trips.

    I submit to you that there is something very wrong with your car.
  • I do believe what you say. I have a 2008 335xi and I noticed that in city traffic when driven in automatic (basically a stop sign at every intersection in the uber regular grid of Chicago south side) the car would scantily make it to 15 mpg. On the 36k+ miles run up to now the overall mileage I am getting is 21 mpg. It could definitely be better but I tend to drive highway miles at rather sustained speed (and use the manual transmission mode). Using the option of actual estimation of MPG while driving I tend to get a 21 mpg estimate on highway at around 2400 to 2700 rpm depending on the incline of the road. Overall I am satisfied since all the numbers come down to mean a full tank a week for me anyway.
  • mmejiammejia Posts: 9
    I drive a 2007 328i coupe, auto transmission. I am getting 25.5 avg mpg driving in the city and highway. When I was do lots of city driving it was 24. I am very happy. Has 65000 miles on it now.
    Thanks for reading. ;)
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