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Infiniti M35/M45 Real World MPG

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Comments

  • mwgmwg Member Posts: 28
    Recently took my first highway trip with my M35X. Set the comnputer when I got on the highway and read it when I got off. So it was all pure highway mileage. To my suprise I got 27 MPG.Use top grade gas and have driven the car only 1700 miles. Suprised because our normal driving is 1 and 2 mile trips to supermarket,barber,friends, etc. during which we get mileage as low as 10-12MPG.

    EmGee
  • ribbonkingribbonking Member Posts: 24
    Drove from LA to Las Vegas last week. MPG was 24.5 driving at 75 - 80 MPH on cruise control.
  • blov8rblov8r Member Posts: 567
    My last car was a Caddy DeVille ... 28 mpg on the hiway @ 75 mph. Can't touch that w/ my M. Doesn't matter ... just a comment. Bart
  • cdnpinheadcdnpinhead Member Posts: 5,499
    It's mostly about RPM at cruising speed.

    That and ULEV.
    '08 Acura TSX, '17 Subaru Forester
  • aaficionadoaaficionado Member Posts: 5
    Bought M35 non-sport in January 2006. Great car! Learned to manage my foot on the accelerator, it's a habit now, although somewhat disconcerting when I have to drive a rental car during an out of town business trip. Use premium gas. Get right at 18 mpg, with 50% city street driving. The other 50% is what I call metro-area hwy driving - meaning hop up on to an interstate, and drive 10-20 miles to get to another part of town. Have not done any true long distance hwy driving... i.e. hundreds of miles on a single trip.
  • tstreettstreet Member Posts: 4
    I commute 28 miles one-way with about 20 being on the freeway. After 16 months the computer reads my overall average is 20.2 I always use premium fuel.
  • blueskies2blueskies2 Member Posts: 3
    I have found that mileage is better if you use the manual shift mode. The D (automatic setting) always keeps the gear in position for maximum performance. For the best mileage, it is best to keep the car in 4th or 5th gear. Manual mode lets you select higher gears at the expense of acceleration (though it is still plenty of power for everyday driving).

    And when you want the max performance you can manually select lower gears.
  • joegolfer1joegolfer1 Member Posts: 17
    I have an '06 M35x and I am getting 19 mpg. I have only checked gas mileage twice in 10,000 miles.

    Prior car was a 2003 M45 and I got 20 mpg. Not unhappy but I did think my gas mileage would go up with the new one.

    On another subject, the M45 was terrifying in the snow and M35x is a beast. Very happy.
  • shmangshmang Member Posts: 297
    All:

    Are there any M45 owners (prefer over 1 year old, so it shows broke in gas mileage) that can share their gas mileage as well as the driving style and city/highway %.

    I have a M45 and it seems that I basically get same city or highway, which is around 20 (say 18.5 city and 20.3 highway). Is this normal?
  • tayl0rdtayl0rd Member Posts: 1,926
    Dang! You couldn't wait until Feb 8 to ask that question? :cry: We were headed full-on into 2 years of nobody caring about the gas mileage of this car! :P
  • shmangshmang Member Posts: 297
    Maybe all the M45 (and M35) owners are used to the terrible gas mileage and trying to forget about the pain? For now, the gas price is low, so no big deal, but it must be hurting back in late 2007 and majority of 2008. :mad:

    I am used to the bad mileage already, but just feel it odd that I get almost the same gas mileage on city and highway - well a little over 1.5 MPG difference. This is not normal to me, thus the post/question.

    Anyone mind share their experiences/thoughts? ;)
  • avj23avj23 Member Posts: 4
    I have a new 2008 M35x with 500 miles on it that is getting about 10 MPG (mostly city) and revving high 2900 RPM's at 70 mph. It does not seem to go into overdrive. Has anyone else had this issue or do you think it will improve after some additional miles?
  • shmangshmang Member Posts: 297
    If it is at 2900rpm at 70mph, it is in overdrive. The M is geared for performance and you are already in the overdrive gear. Mine is the same (as well as other ones I test drove). On my Honda, it revs at 3550rpm in 5th gear at 70mph (again, sporty car and geared for performance).

    Even for break in period, with AWD, 10MPG seems low. Unless it is very congested city and you have a lead foot and somewhat short trip (less than 10 miles each way). I get 15 when driving very aggressive in heavy city traffic and get 18 when take it easy.
  • avj23avj23 Member Posts: 4
    Been driving easy during the break-in period so it could get worse if I drive agressively. If the car truely revs at 2900 RPM's at 70 MPH, I think that would explain the gas mileage. In the last two days I've been in a Scion and Chevy Cobalt that were revving at under 2500 RPM's at 70 MPH.
  • 150mphclub150mphclub Member Posts: 316
    My 2009 Cadillac CTS revs between 2100 & 2200 at 70. I guess that explains the Infiniti reputation for bad fuel mileage.
  • shmangshmang Member Posts: 297
    Well, the high revs does not necessarily explain the bad gas mileage. Just as I said, my Honda revs higher and get 32 MPG on the highway (at 70MPH), which is a number the CTS can not reach. Not sure about the Scion or Cobalt though. But they are much lighter and has much less hp to begin with.

    Infiniti could build a more efficient engine, but I think fuel economy is simply not their focus point.
  • avj23avj23 Member Posts: 4
    Is yours AWD? What kind of MPG are you getting and what kind of driving.
  • 150mphclub150mphclub Member Posts: 316
    Automatic, RWD. 95% highway (usually about 75mph), 27 mpg.
  • james27james27 Member Posts: 433
    I have a 2006 M35x. Mostly highway, it's about 20-miles to work, and I typically get around 20mpg, the best I've done is about 26. If I spend a lot of time in the city (not very often), it does drop to the mid-teens. I do drive fast, but don't put my foot into it that often. Definately not in the slow lane.
  • shmangshmang Member Posts: 297
    Well, that sounds about right, except the 26MPG. I have never been able to get anywhere close to that - even when fuel economy is top priority. The best I got so far is 23.2 on highway 65mph, 70F, no A/C.

    What did you do to get to around 26? I need to know in case the gas price goes to $4/gallon again :cry:
  • james27james27 Member Posts: 433
    200 miles on cruise control with gas that didn't have any ethanol in it, cool, but not super cold, level roads, no traffic. Per volume, alcohol doesn't have as much energy as gasoline and lowers your mileage. Hard to find depending on the locale and the season, but does make a difference. It helps if you run the tires at the high end of the recommended range as well.
  • palincalpalincal Member Posts: 4
    2900 RPM at 70mph is normal for an M35. It is designed to rev high for sportiness. Check you trip computer for you av. speed. I get 19.5 MPG for an av. speed of 30mph. Keep you tires at 34-35 PSI. Use premium gas from a quality brand. Keep the windows up will driving above 40mph. If nothing works you have a problem. 10 MPG is too low even for a new car.
  • AboutTreeFiddyAboutTreeFiddy Member Posts: 1
    Note the 2009 M35 RWD with the new 7 speed trans has higher top gear. I'm seeing exactly 2000 rpm @ 60mph which would put it at about 2350 @ 70mph (I'll check it @ 70 next time I'm out). My first half tank was 23 mpg (computer) with probably 70% highway, 25% suburban & 5% stop and go (easy driving during break-in).
  • avj23avj23 Member Posts: 4
    Have just over 800 miles on the car now and still averaging at best 12 mpg almost all city/short trips. Took it in to the dealer and they said its fine, "it should improve slightly after break-in period." Wish I would've checked this site first might not have bought it. Nice car though.
  • james27james27 Member Posts: 433
    Short trips, cold starts, stop and go will always be a problem with a high-performance car, especially one weighing about two-tons. You might want to use the trip computer and see what your average mph and distance traveled is...my guess is the car might not be fully warmed up and you spend more time idling than you think. A diesel works much better, since it is very efficient at idle.
  • infinitim35infinitim35 Member Posts: 5
    I have an used infiniti m35 sport 2006. It currently have 67k miles and I have been suffering terrible mpg driving here in nyc. My city driving at best is around 10.5 mpg. My combine city/highway is around 16mpg. Anyone know what is wrong with my car? Is this normal for nyc driving? It is not even heavy traffic where I live. I bought this car to the dealer and they told me this is normal.
  • shmangshmang Member Posts: 297
    What is your daily commute distance (each trip)? When you say city, was that like a stop light every quarter mile to half mile? What is the % for your combined drive, like 40% highway, 60% city?

    Keep in mind, the M is very thirsty to begin with.
  • infinitim35infinitim35 Member Posts: 5
    I commute about 5 miles round trip. City driving as like stop light every block or every two blocks. It's not like one block the light will be green and the next block is red. It is consistent most of the time so I don't have to stop until like 5 blocks. My combine driving is about 30% highway and 70% city. Is this normal to get 10mpg? sometimes even 9mpg? I thought my fuel injector was dirty or something since it was a used car but I add some additive and it still didn't help much.
  • james27james27 Member Posts: 433
    In 2.5 miles (your one-way trip distance?), the car is not warmed up. Yes, the temp gauge will say it is, but it takes longer than that to fully warm up everything. In that time, the car will be using more gas. You're just getting to the point where it can start to hit its peak when you shut it off.

    I have a 2006 M35x and my average tank mileage is about 20-21mpg, but I travel 19-miles, mostly highway each way to work. My mileage went up a little (maybe around 1mpg) when I switched to synthetic oil. I've had the oil tested periodically, and can safely run about 10k miles between oil and filter changes. You probably wouldn't want to do that with all of those short trips.

    In NYC you might get run over by the cabbies if you don't accellerate fairly quickly, but it can make a huge difference if you take it a little easier, and don't brake late when you see the light is red ahead of you.

    I'm seriously considering a new Mercedes E-class diesel. It should be great in short trips and on the highway (rated at 32mpg highway).
  • infinitim35infinitim35 Member Posts: 5
    Well I don't live in NYC where there is a lot of cabs. I live in brooklyn which is more regular streets. I don't really think it has to do with the car warming up because from time to time, I let the car warm up for 5 minutes before I drive and it is the same thing. I drove 10 miles before I reset my computer and I am still driving at around 10 mpg city. I was thinking about getting a fuel injection cleaning and switching to mobil 1 to see if it helps. My friends m35x is getting about 13-14 mpg city driving compare to mine 9-10mpg.
  • shmangshmang Member Posts: 297
    I believe your short trip is the key - if you let the car warm up (by not driving it), it just make your MPG looks worse, since it is calculated based on miles driven divided by gas used. When idling for warm up, you get zero MPG. I would let the engine warm up for 20-30 sec. at most and then drive moderately for a mile or so before go pass 3.5K rpm.

    So, with your short trip and a lot of stop light, 10-13 MPG is not a surprise. I have a M45 and if I reset the trip computer at start up and drive the first 2 miles (45 MPH zone with basically no light), my MPG reading would be somewhere around 13, but since my commute is 22 miles one way, I normally get 17-18 without A/C and 15-17 with A/C.

    So, short trip makes the car running at inefficient zone all the time - so it is not a surprise for your MPG. If you are driving a small I-4, this is not that noticeable, but for a big 6 (or 8), it is a very significant factor. Next time, reset your MPG calculation before hit a highway and run at least 15 miles and see what MPG you get. I will be surprised if it is not over 20.
  • infinitim35infinitim35 Member Posts: 5
    So should I even bother doing a fuel injection cleaning and switch to mobil 1 or live with the fact that my car will always average around 10mpg.
  • shmangshmang Member Posts: 297
    If for fuel economy purpose, I would not do either. But for better care of the car, mobile 1 sounds like a good choice, but you still need to change the oil every 7500 miles or 6 month which ever comes first - consider your short trip and stop & go traffic, which is very hard on the engine.

    What;s more important is: make sure you run the car for at least 15 miles one way once a month (or more often) with a few good accelerations. This will clear up all the carbon build up in the engine caused by all those short trips.
  • infinitim35infinitim35 Member Posts: 5
    Isn't it when you get mobil 1 you don't have to change the oil as frequently? Thats what the mobil 1 extended performance claims to do?
  • nolicnolic Member Posts: 11
    Inflated tire pressure to 34 PSI on my 2008 M35 increased my average MPG (combine) to about 18 - 19 and I also used Mobil 1 synthetic oil (5W30).
  • shmangshmang Member Posts: 297
    Isn't it when you get mobil 1 you don't have to change the oil as frequently? Thats what the mobil 1 extended performance claims to do?

    That is correct. But, with your driving style, I would change oil more frequently, since short trips are hard on the engine. So, with regular oil, I would do it every 3000 miles and with Mobile 1, you can extend it to about 7500 miles, but, still, I would NOT go way pass 6 month (7-8 month might be OK) though.

    Yes, inflate the tire to 34 PSI will provide improved MPG - with some sacrifice of riding quality, not by much though.
  • carlosc52carlosc52 Member Posts: 1
    I have owned an '06 M35 RWD since April '05 which currently has 82,500 miles on it. I live in South FL, commute 60 miles each way averaging 21.8 mpg running between 75-80 mph. My only complaint is the high RPM (3,000 @ 80 MPH). Presume that the newer models with 7 sp tranny will help...
  • m4mm4m Member Posts: 76
    Atlanta, GA to Orlando, FL: Trip Computer: 497 miles, Elapsed time: 7hr 19 min. for an average speed of: 75.3 MPH. Some luggage and about 1/2 way there and back A/C was on. LOTS of cops but they were all busy writing tickets. Still saw 90+ a couple times.
    Speed limits vary from 55 to 70 with probably 70% of the trip at 70mph.

    So, overall MPG for this trip, with an average speed of about 75MPH, turned out to be 23.8 MPG on premium. And I blew the doors off an Audi A6 and a GS350. Probably dropped my average by 1!
  • mltsurgermltsurger Member Posts: 102
    I have a M45X with 20,300 miles at this time.I love driving it and try to drive responsibly,but the sound when punching it is great.I average 21 miles to the gallon.It recently has been very cold and am getting around 20.I always use B.P. white Premium.
  • mltsurgermltsurger Member Posts: 102
    Sounds like a fun trip.How many gas stops? Has anyone ever gone over 140 mph with the infin.It is supposed to go 155.You really wonder about the handling at 140.If my driveway was longer I would like to try.
  • james27james27 Member Posts: 433
    As more details come out on the new M's, a couple just don't make sense to me: the new models get LESS fuel economy than the ones they replace, and, they have less headroom than the outgoing model. These are two areas that are a major concern for my new car search criteria. The M was near/at the top of the class in headroom, which is why I bought it. Decent gas mileage was a goal, but not crucial as long as I fit. Both parameters went in the wrong direction. So, it's search other platforms for my next car...they lost me as a customer. Next year's hybrid might improve part of that, but unlikely to recover the lost headroom.
  • dallasm35dallasm35 Member Posts: 1
    Yes I have got 2007 m35 up 160. It was flying.I strongly recommended you trying it out.
  • smarty666smarty666 Member Posts: 1,503
    I know some people are going to say that this is phony baloney but I have personally found out that what gas you use does make sometimes a 4-5mpg difference in a car; I used to use Exxon and Hess 93 Octane in my 2010 Max Sv AND 2005 FX35 and was barely getting EPA on the sticker for mpg!

    I got so fet up that I switched to Shell 93 Octane, after several family members and friends recommended it and after about 4-5 fillups with Shell I noticed a dramatic improvement in all mpg categories, city, highway, avg, etc!

    Just a suggestion to help clean out your engines and get better fuel economy; if you don't have a Shell near you try using turkey hill or one of the other top tier gasoline companies!!
  • ghstudioghstudio Member Posts: 972
    I'm going to try this. In the past I've found no difference between using regular and mid grade and premium....which suprised me. I'll give Shell premium a try.

    One problem is that octane ratings aren't all equal....some measure a the bulk tank, some measure at the pump some probably measure in the lab. I always have this lingering concern because all the gas you see in those huge bulk tanks is regular and the higher octane is created by adding additives at the bulk plant or at the truck. Those additives cost money and they require a human to so something to add the additive. There is a cost incentive to maybe miss adding anything. I know, it's paranoia....but there really is no way to know what you a putting in your tank. Now when you use an off-brand, you are really taking your car's life into your own hands...because those stations have chosen to make more money by offering an off-brand....so maybe saving a little more is even better.

    Darn...where is my shrink when I need him?
This discussion has been closed.