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Chevrolet Cobalt Real World MPG



  • pa356228pa356228 Posts: 34
    My doorframe says 30 psi but the tires says never to exceed 40 psi. Strange world. Guess we will never know. Funny how the world works, but my advice I can give is just go what best suits you.

    My uncle is a mechanic, for his cars he always put 32 psi in all his tires and even with my cars. He never had problems with 32. Today, I set all my tires at 30 psi, according to the doorframe and see how well that goes for gas mileage and tires for a week or two. Also, some tire shops, have hydrogen tires which they said will also increase gas improvements and last longer than original tires.

    Also, I drive a 2006 Chevy Colbalt LS (4-doors sedan) now with 51,303 miles. I will take my car in for an oil change on tuesday and going on a long trip on wednesday VB,VA to Pittsburgh, PA (450 miles or 8 hrs) and will calculate m/g/mph to accurate mpg. I'll post results.
  • tsjaytsjay Posts: 4,591
    I think you mean nitrogen, not hydrogen.

    The same tires are used on different vehicles, and the max pressure indicated on the tire itself is not indicative of where the pressure should be run on a particular vehicle; it just means that that pressure should not be exceeded.

    The optimum air pressure is very much related to the vehicle weight. For lighter vehicles, less air pressure is needed, and for heavier vehicles, higher air pressure is needed.

    What you are looking for is a good "footprint." You want the tread all the way across the tire to be in contact with the road. Over-inflation makes only the tread in the middle of the tire make contact with the road and will cause the tread to wear more in the middle. Low air pressure will make the inside and outside tread make more contact with the road, and the edges will wear out faster.

    Some people actually rub chalk across the tread, drive a few feet, and then check the footprint the chalk made. Not too many people go to that much trouble. Just stick with the manufacturer's recommendation, and you should be OK.

  • pa356228pa356228 Posts: 34
    That is a good way to look at things, meaning that the companies who make these cars suggest putting a sticker of tire pressure psi on the doorframe, why not use it?

    If we didn't, why would the company waste time and money on something that we won't bother with. Most people who cares about their vehicles would love to get most out of their money. Everyone should do the same, especially when the economy is bad and will only get worst.

    Of course, some people don't care that much about their vehicle and would rather buy tires if they absolutely have to. (to pass state inspections) Why would spend extra money for lazyness. Never really give enough thought about it, until now. Thanks Tom.
  • eliaselias Posts: 1,898
    I've done the tire-chalk test in years past, with a Z28...
    I like it when street cars wear the tires perfectly flat like my 5 3rd, 4th gen f-body/Z28 cars always did.

    currently I drive an 06 VW jetta, and an 05 Pontiac GTO, both manual shift.
    The VW wears the tires nice & flat. GTO not so.
    Anyway, I really like the blue cobalts and would consider one at some point (with manual shifter of course).

    i'd bet that cobalts wear the tires nice & evenly, if you select the right PSI and
    only participate in drifting exhibitions every *other* weekend.
  • dispencer2dispencer2 Posts: 295
    I was suprised on my last trip from Clovis to Albuquerque. I stayed at about 68 mph until I reached the Interstate at Clines Corners and got 40 on an average for about 100 miles. Total average for the trip was around 38 .Altitudes are relatively high - 4300' at Clovis and I think that Albuquerque is around 5,000.. The drive is hilly only when you are going through the Sandias just east of Albuquerque. I have the small 4 and automatic on an LT1 coupe. The car has around 3500 miles on it. I am very critical when it comes to cars. I disliked the jerky transmission on my 06 Impala and finally sold it. I bought the Cobalt last September and have no complaints at all except for very little CD storage in the console. The ride isn't much different than the Impala. The electric steering is tricky at high speeds -you need to keep your mind on the road. A slight deviation and you are in the other lane. Pickup is fine as long as you realize you don't have a Maserati when you pass someone. All in all it is a great car. I am really suprised that Chevy is dumping it. I won't get a Cruse until they build a coupe.and probably by the time I sell the Cobalt the Cruse will be a thing of the past.
  • pa356228pa356228 Posts: 34
    Got back 3 days ago. Anyways, I drove from Virginia Beach, VA to Sarver, PA and it took me 9 hours or 454 miles. Had to stop once for fuel, at Sheetz in Breezewood, PA for $1.93 /gal on Route 522 W. Anyways, When I got to Sarver, PA my car calculated 35.8 mpg mostly highway driving at 60 mph.

    When I drove back to Virginia Beach, VA at 65 mph, it took 8 hours and 13 mins. (443 miles) My car calculated 35.3 mpg, and never had to stop for fuel. Drive straight thru. At tire(s) pressure set at 30psi according to the doorframe. I can't complain. Intending on moving back up there before June 2009, it was great.
  • gigimjgigimj Posts: 1
    Just wanted to comment ... I drive 75-80 miles round trip to work daily in city/hwy traffic in Dallas/FtWorth .. I average 32-33 mpg. I have a Cobalt sedan 2007. My daughter has a Cobalt coupe 2007. I just took a trip to Houston last weekend driving 60 mph with no AC on with some rain and averaged 41.3 mpg with an average speed of 57 calculated by the onboard computer in the car. When I first got the car I went to Atlanta GA and averaged over 37 mpg I remember. The car has 45,000 plus miles on it now and 2 yrs old .. yes I drive a lot! I just had the car inspected, oil and oil filter changed, all new tires, new fuel filter, new air filter, and new wiper inserts. I'm driving to Houston again this weekend ... hoping for even better milage this time ... maybe better then 42 mpg!!! Anyway just wanted to say how impressed I am with this Cobalt ... bought it new 2 yrs ago a week after my daughter bought her coupe. I'm 62 nearly and have owned a lot of cars in my time. Once I would not go near a Chevolet ... that has changed! I have had in my lifetime a 1966 Olds Cutlass 442, 1967 Corvett, 1968 Corvett, 1972 Toyota Celica, 1973 Toyota Corona, 1974 Toyota Corona, 1976 Fiat, 1977 Buick Regal Tubo, 1978 Audi 2000S, 1980 Mazda RX7, 1982 Honda Accord, 1985 Ford F250 HD SuperCab Diesel, 1988 Mitsubishi Pickup, 1994 Jeep Cherokee, 1998 Ford EddieBauer Explorer which I still have with just over 149,000 miles and my 2007 Chevy Cobalt. All these vehicles were bought new from first to last. My 1966 442 got 17 mpg, my 1972 Celica got better then 32 mpg, and my Chevy Cobalt better then 41 mpg .... yeaaaaa!

    How are the rest of you doing with the Cobalt??????

  • dft56dft56 Posts: 8
    I have a 2007 LS 4dr sedan and live in NY, around town i get 29mpg and on long trips between 38-42mpg. Am quite happy with my Cobalt despite a few trips to the dealer for front end work(all under warranty). Seems the bushings are not as good as they used to be.
  • steve333steve333 Posts: 200
    Hi, My front end feels funky, I was wondering what your front end symptoms were when you got the bushings replaced. Thanks.
  • pvs68pvs68 Posts: 2
    I just rented a Pontiac GS (Identical to Cobalt) and according to the in car computer was getting 38 MPG on the highway with spirited driving from NC to ME and back, more than 2500 miles. This was with an automatic transmission too! I was impressed since it zipped along too.
  • Picked up my 09 Cobalt LS/XFE with the five speed a little over a week ago, and have no problem getting 43 to 44 on the freeway. Doing 70 in fifth, with the A/C on.
    This little car amazes me.
  • pa356228pa356228 Posts: 34
    Now, I've being alittle mixture of driving on the Interstate and city. My Cobalt LS is averaging out 31.4 mpg. It was 32.4 but right now my cobalt is about 3,000 miles overdue and will definitely get an Oil Change tomorrow morning (08/21/2009) so, hopefully the mpg will raise back up. Also, my tires are set at 32psi. By the way, my car is automatic, wished I had a 5 speed. Although, I do know how to drive a 10 speed BigRig.
  • I rented a Cobalt in 2007 and played around with various speeds/rpms to see what produced the best MPG (according to the car computer), and found that if I activated the cruise control, while accelerating, right after it switched to the highest gear (4th?), the speed would be maintained at about 38 or 39 mph, and the MPG would register at 58 or 59 mpg. This was when the tires were a little over-inflated (a hot day), and on a very smooth pavement. I watched the mpg drop by 4 or 5 mpg when the road surface changed to very rough (the kind of road that is very loud to drive on). My question is, is the car computer readout of mpg accurate? (if I actually drove a few hundred miles with this setting, and measured the gas comsumption, would the reported mpg have calculated out to be true?) The reason I ask is that I am considering buying a Cobalt, and want to know if the computer mpg is accurate.
  • eliaselias Posts: 1,898
    Car dashboard mpg computers/displays are not very accurate in my experience - often reporting much more mpg than the car is actually getting.
    So no, had you measured distance/gallons, you would have come up with a substantially lower number. Maybe 39 mpg at most, I'd guess.
    But any given mpg-meter tends to be accurate for measuring *relative* mpg differences within that one vehicle.
    So when you saw indicated mpg drop from 58 mpg to 54 mpg, you can be pretty sure that the instantaneous fuel consumption had indeed dropped by ((4/58)*100) %.
    Once you establish the "overestimate" that the dashboard-mpg-meter provides, you can subtract a fixed percentage from whatever it tells you.
    For example, my VW TDI mpg dashboard-computer reads consistently about 10% above the actual mpg, typically reporting 50 mpg over an entire tank that actually yielded 45 mpg.
  • In my 2008 the car keeps very good track of the gas mileage. Keep in mind that the MPG displayed in the DIC is only representative for the last hour of driving. So you may have done 200 miles of highway at 35 mpg and 100 city, heavy stop and go and the car may display 28 or less. But when you fill the tank you will most likely see that you actually got 31 or 32 mpg for the whole tank. For a 300 mile trip from Central PA to Western NY I generally get 34 to 35 mpg. That's a lot of mountains as I venture north at 65 or 70 mph. I keep my tires at 30 psi cold as the car recommends. I have 19000 miles on my car and keep track of every drop of gasoline that the car consumes. My average since I bought the car is 33 mpg.
  • When I first brought (or still leasing yet.) it was calculating 27 mpg at the first 105 miles on the car. When I used to live in PA, my cobalt was getting about 31. Temporary living in VA, as my car was getting 34 mpg. Then, recently about a month ago, my car was still getting 34 consistent. Until, last Wednesday, My cobalt LS dropped to 29.3. Can't fiqure out why.

    Guess, no mpg is accurate on cobalts sensor systems. My manager from work, told me and old fashion trick to know for sure exactly what your car mpg aveage. He told me, just to first, fill up your tank, reset your trip A and Trip B miles. Then, keep track of all your miles, and when it's time to fill up. Check your miles and divide that from how many gallons your car holds. He said, that will be your most accurate. Of course, it all depends on how fast you drive, tires psi set at, and other misc... I haven't tried it yet but, this coming week on Tuesday thru Sunday, I will. Next week, I'm driving back up to PA on a 443.5 miles trip (about 8 hrs.)

    Is there any other tricks to use?
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,046
    > My cobalt LS dropped to 29.3. Can't fiqure out why.

    The changeover to winter fuels may have dropped the BTUs in the fuel. Lower mileage than the summer blends.
  • eliaselias Posts: 1,898
    it's not really a "trick" to determine mpg by dividing miles by gallons, but since you asked, how's this:
    you could use a super-precision scale to weigh the car, drive a certain distance, then
    measure its exact weight again.
    no stopping for burgers or a caf-pow or shopping or hitchikers or rest-areas.
    the change in weight divided by 9 lbs would be the # of gallons used. then divide
    that into the distance in miles and you have mpg.
  • When I arrived here in Pittsburgh from Virginia Beach, My Cobalt LS mpg reach back to normal 35.4. Two days ago, it fell to 32.5. Did notice the difference BTU's. Guess, they figure no one will want to drive in the winter, besides to get what is necessary. So, no one will care about the mpg. Crazy world we live in.

    I'll keep updating now and then, so be patience. Sure feels great to be back home officially. See ya later...
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