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Chevrolet Suburban and GMC Tahoe MPG - Real World Numbers

13

Comments

  • 73shark73shark Member Posts: 325
    LTZs also have 2WD and only the 5.3 V8.
  • 73shark73shark Member Posts: 325
    I've tried this in city driving and noticed the apparent increased acceleration from a stop. Might be due to the torque management system. Also noticed that the torque convertor lockup is delayed or never happens. Will try on the road next time and see if mpg improves.
  • rspencerrspencer Member Posts: 63
    You are so right about that.

    There's something else that stands out about the question...what's real world MPG for the Tahoe(or Suburban)?

    I cannot find any research done by Edmunds in their 40 years that tries to answer that question. Not limited to only the GM products...

    Taking Chrysler-D-Benz's/Ford's/GM's, etc.'s word,...taking EPA's word...is all Edmunds seems willing to do. Why be a source for misinformation? Why not show some courage and independent action?

    Read the study that Consumer's Union did. It is an eye opener. They test EPA MPG ratings on 303 cars & trucks...and 270 fail. They weigh 303 cars and trucks...and curb weights are not what the manufacturers say they are. Most are understated by the mfg. by hundreds of pounds.

    CU finds Tahoe 5.3L gets 9 MPG city. Edmunds site for Tahoe says 16 city...

    9 MPG vs 16 MPG...

    What are these trends saying...Caveat Emptor? Buyer Beware?

    It's just deja vu...all over again.
  • steverstever Guest Posts: 52,454
    If you go to the Road Tests tab/page, you'll see that many of the road tests report on mpg. Plus mpg is recorded for the cars in the long term test fleet, but there hasn't been a GM SUV in the fleet in recent years.

    The editors observed 13.5 mpg for the '07 Tahoe in the Full Test. I don't see a Follow Up test for the Tahoe yet.
  • jay_24jay_24 Member Posts: 536
    How do you think most of these groups that test cars/trucks/SUVs drive them? Lets see, the do a couple drag races to get 0 to 60 times. Then run it hard as it can go in a slalom corse to see how it goes around little orange cones. Then get it upto 70 and slam on the brakes... then how much does it sit and idle?(at zero mpg). Then they complain that it has a bit too much body roll @52.5mph on the slalom. Gee is that real world?

    Hence every car/truck/van/SUV I've owned has gotten well better that what any test group reported and often slightly better than the EPA numbers.

    Maybe you should get a Honda Pilot. One guy is getting 12 something MPG.
  • arriearrie Member Posts: 312
    Posting MPG numbers alone do not do any favor to anybody as no-one drives the same way.

    If we want to compare MPG numbers between different vehicles then driving condition also must be the same.

    The only real MPG number you really can compare is when you take it from a constant speed driving trip. This means that you fill up your tank all the way to the cap, yes, ALL THE WAY. Then get on highway and drive a good distance with cruise on with the same speed. And yes, there should be no head wind, tail wind or drafting behind other vehicles. Then you go to a gas station and fill it up again to the cap.

    This is very easy for me to do as I drive long distances, sometimes 11 hours one way without stopping other than to fill up, and to the cap every time. When I fill it up it is a simple calculation to see the real MPG number, as I reset the trip counter at every fill up. And most of the time the average MPG display in my Tahoe is inside 0.3 of the actual number.

    If you go drive on highway for this you will see how quickly the increase in speed lowers MPG. My Tahoe goes 18 MPG on interstate highway with speed 75 - 77 mph. If I drop it down to 60 MPH I get 22 MPG. At speed 45 MPH I get 25 MPG, which is about the best it gets. Going slower does not really improve it further.

    MPG numbers that are shown at car dealers have been generated by a specific driving pattern and I believe these numbers are very correct.

    One reason for difference between these MPG numbers and today's 'real world' numbers is that the driving pattern used in the test comes from so far back that highway driving speed portion of that pattern is with much slower speed than what we all pretty much today do.

    Just for reference, in Europe when they display L/100km for any vehicle it is fuel consumption of the car with constant speed on highway, and that speed is only 90 km/h, which calculates to 56.25 MPH.

    --Arrie--
  • rspencerrspencer Member Posts: 63
    No assumptions made whatsoever. Take the research that is reported at face value. Test protocols are usually described in the report.

    CU's report is open to all and there for anyone to consider. The work they did withstands scientific scrutiny. The team of Ph.D.'s worked hard to get at the facts.

    They didn't do any of the things your post describes.

    They did drive on real roads. They did not base their data on dynamometer testing...like the EPA does.

    How many dyno's do you all drive on when yer' going in to the plant or the office?

    I don't drive on any.
  • rspencerrspencer Member Posts: 63
    Arrie Says: Posting MPG numbers alone do not do any favor to anybody as no-one drives the same way.
    ------------------------------------------------------------

    That's not what most people believe. Accurate MPG numbers are more important than you might think.

    Not only do they help us make good choices when we budget for the purchase of a car or truck. They also help our elected officials make better energy policy choices.

    There has been a longstanding public concern about the national need to require better vehicle fuel economy across the fleet of passenger vehicles. America’s dependence on foreign oil is a national security concern. The fact that two-thirds of the oil consumed in the United States today is used for passenger vehicles tells us that the nation needs to accurately assess and improve fuel efficiency to the maximum extent possible, consistent with what is technologically and economically feasible. We are also concerned with the effects of ever-increasing emissions on air quality, on the environment, and the increased threat of global warming. All of these problems make accuracy in fuel economy ratings more immediate than ever.
  • rspencerrspencer Member Posts: 63
    arrie sys - MPG numbers that are shown at car dealers have been generated by a specific driving pattern and I believe these numbers are very correct.
    ------------------------------------------------------------
    Believing in the MPG numbers?...sure that's a good thing. Nobody wants to use a forked stick to make major financial decisions.

    Are they correct? Do you mean accurate? Very accurate??

    If you mean very accurate...your work is cut out for you.

    You might want to start with the U.S. Senate Committee on Energy and Natural Resources. Right now they flat out don't believe you.


    Section 774 of EPACT 2005 instructs the EPA to create new fuel economy measurements that more accurately reflect today’s speed limits, city driving conditions and the use of air conditioning and other fuel depleting features.

    Was it reasonable to use 45 miles per hour as the representative highway speed for testing for 21 years?

    Are city driving conditions in Los Angeles representative of most city driving conditions in our country?

    Do we not use A/C to survive the heat and humidity in places like the south half of the U.S.?

    Oh yeah...don't take my word for it.

    From te U.S. Senate Committe on Energy and Natural Resources...

    Chairman's statement:

    “The EPA hasn’t updated fuel economy estimates since 1985. We instructed the EPA to update their fuel economy estimates after hearing from frustrated and disappointed consumers who weren’t getting the mileage from their vehicles that advertisements had led them to expect.

    “I consider this provision in the energy bill one of the most potent consumer protections in the bill. It will literally influence how American consumers spend tens of thousands of dollars. Buying a vehicle is one of the most expensive choices a family will make. With gasoline hovering at $2.50 a gallon, fuel economy estimates play a huge role in that choice. I am pleased that the EPA is moving swiftly to implement this provision in the energy bill.”

    Good luck arrie...
  • rspencerrspencer Member Posts: 63
    Just checked with GM. They say the towing mode should do the opposite to MPG.
  • arriearrie Member Posts: 312
    rspencer,

    I don't know what your problem is. Anybody else who might please help me...

    I said the only sure way to know a car's MPG number is to drive on highway with constant speed and by filling the tank up to the cap to make sure you know how much fuel you used for a distance. I can guarantee you that this really is the only way to compare vehicles between common men as we do not have the specific driving pattern to use for testing nor do we drive similarly.

    I only meant that for everyday man it is the only way to compare vehicle MPG, i.e. if you would go test driving before purchase. In practice this doesn't work as nobody wants to fill up dealer's demos to the cap for this.

    Then, I think I mentioned that the EPA driving pattern is old and specifically mentioned that the speed for highway driving portion must be much slower than we drive today.

    By saying that I believe the displayed MPG numbers at car dealers are accurate I meant that they show what MPG is if you drive by the test pattern EPA uses. I did not mean that these displayed MPG numbers necessarily mean what today's normal driving would produce.

    Is there someone else who got this wrong? If so, please accept my apology.

    --Arrie--
  • arriearrie Member Posts: 312
    GM also (or the dealer) said that there is no problems in my '04 Tahoe when I found and fixed several by myself while the truck was under warranty. One of them being 13 MPG fuel economy on highway where it now after my own fix goes 18 MPG. I'm sure they would find all sorts of problems now when it is beyond 36 000 miles.

    You believe who you like. I believe what I know and see. My truck gets better MPG when towing mode is activated and while I drive faster than 60 MPH. GM saying it should be worse is true if you drive in city and your truck never uses the highest gear (or locks the converter). Over 60 MPH is the key here.

    The reason for this I believe is that there are two different gear shifting programs, as we know, that not only control the time of shifting but also control the shifting firmness / smoothness.

    In an automatic gearbox shifting is done by switching tension between belts (I'm sure you know this) or pressure between multi-disk packs, i.e. you let tension off the belt for 2nd gear and at the same time increase tension for 3rd gear belt when shifting up from 2nd gear. The tension ratio and amount in these belts determine how smooth the gear shift is and when some tension is kept on the belts at the same time the smoothest shift can be achieved. If you just let 2nd gear belt loose and put all tension on 3rd gear belt instantly you get a big jerk. You also can get a slip between gear changes.

    My believe now is that in towing mode the gear change program has been made to minimize the drag, i.e. the tension for belts other than the gear in use have been minimized for better pulling force and MPG. This is also obvious at gear shifts as it jerks a little bit when towing mode is on. They can do this as nobody complains about a small jerk when pulling a trailer, right?

    Also, this explains why my Tahoe noticeably takes off from stand quicker than with gears in normal mode. From a stand in both modes it takes off using 1st gear and there should not be any difference unless something that I explained above is really happening.

    --Arrie--
  • rspencerrspencer Member Posts: 63
    jay_24 says. Maybe you should get a Honda Pilot.
    -----------------------------------------------------------

    Thanks - but I'll pass on the Pilot. And stay with the Tahoe for now. Maybe u should get a clue...about MPG testing procedures...in the real world.

    If Edmunds is getting ~13 MPG O/A in their long term testing...how do u get ~18 MPG O/A???

    R U into the SDPWF numbers? (Some Day Pigs Will Fly)

    You may be watching too much TV. Be careful not to trip on them lil' orange cones...
  • rspencerrspencer Member Posts: 63
    Posting MPG numbers alone do not do any favor to anybody as no-one drives the same way.

    If we want to compare MPG numbers between different vehicles then driving condition also must be the same.

    The only real MPG number you really can compare is when you take it from a constant speed driving trip. This means that you fill up your tank all the way to the cap, yes, ALL THE WAY. Then get on highway and drive a good distance with cruise on with the same speed. And yes, there should be no head wind, tail wind or drafting behind other vehicles. Then you go to a gas station and fill it up again to the cap.

    This is very easy for me to do as I drive long distances, sometimes 11 hours one way without stopping other than to fill up, and to the cap every time. When I fill it up it is a simple calculation to see the real MPG number, as I reset the trip counter at every fill up. And most of the time the average MPG display in my Tahoe is inside 0.3 of the actual number.

    If you go drive on highway for this you will see how quickly the increase in speed lowers MPG. My Tahoe goes 18 MPG on interstate highway with speed 75 - 77 mph. If I drop it down to 60 MPH I get 22 MPG. At speed 45 MPH I get 25 MPG, which is about the best it gets. Going slower does not really improve it further.

    MPG numbers that are shown at car dealers have been generated by a specific driving pattern and I believe these numbers are very correct.

    One reason for difference between these MPG numbers and today's 'real world' numbers is that the driving pattern used in the test comes from so far back that highway driving speed portion of that pattern is with much slower speed than what we all pretty much today do.

    Just for reference, in Europe when they display L/100km for any vehicle it is fuel consumption of the car with constant speed on highway, and that speed is only 90 km/h, which calculates to 56.25 MPH.

    --Arrie--

    ------------------------------------------------------------
    O.K. - I read the above. So what is your point?
  • tidestertidester Member Posts: 10,059
    Maybe u should get a clue ...

    Clues are great but that kind of posturing doesn't make your case. Let's try to be a bit more respectful of others in the Forums.

    tidester, host
  • eliaselias Member Posts: 2,209
    perhaps there is an imaginary aspect to some folks mpg numbers such that the magnitude of their reported mpg is the square root of the actual mpg squared plus the imaginary component squared. but seriously...

    arrie, if you want to test your fix for improving mpg, reverse it and see if the mpg drops back to about where it was. ? worth a try, for the advancement of humanity?!

    also i wonder if folks are considering the fact that mpg can improve significantly until about 5k or 10k miles as a gasser engine breaks in. for diesels the mpg can improve all the way to 60k miles! ballpark 10% improvement during break-in, imho.

    another factor that can lead to a significant change in mpg is how much ethanol is in the gasoline. if you are near a big city or live in corn-country your gasoline is likely to contain up to 5% or 10% ethanol. in my experience this results in up to a 20% drop in mpg compared to using non-oxygenated gasoline. i hate it when that happens; i think oxygenated fuels are mostly a scam. MTBE was an awful pollutant to water supplies which cost motorists extra money and 10% mpg. ethanol is not as nasty a pollutant but it too costs motorists extra money and even more mpg.
    my repeated tests with early 1990s civics and RFG1 in california indicated that the MTBE oxygenated gas provided significantly better mpg than the ethanol (arco) oxygenated gas, with each providing WAY less mpg than before RFG1 was introduced (thanks to RFG1, my civic EX mpg dropped from 40+ mpg to 28 mpg, during my daily 104 mile 79 mph roundtrip commute. this mpg drop prompted me to return to commuting in a GM V8 subcompact which got about 22 mpg on the same commute, with RFG1. more power, Scotty!).
    "Kirk here, one to beam up..."
  • arriearrie Member Posts: 312
    Did the test already and yes, the MPG dropped. The difference is nearly 1 mpg, i.e. without towing mode activated I get about 17.3 MPG driving highway 75 MPH. With towing mode activated it is about 18.2 MPG with same driving condition.

    And I know my MPG number is very accurate as I fill it up all the way every time and count the miles between fill-ups.

    --Arrie--
  • rspencerrspencer Member Posts: 63
    Amen Brother Elias! Seriously... The whole MTBE thing was just not what it seemed. I saw it develop...actually worked on different process configurations to make it. This goes back to the 70's...when refiners were looking for ways to fight the ethanol "threat". The perceived threat was thought to be a challenge to their basic business model and refining volumes. Now of course, we see that Methyl tertiary-Butyl Ether was actually the bigger threat...to the ground water. Who'da thunk' it...not anyone working on it at the time.

    Underground storage tank leakage...was not on the R&D radar screen at that time.

    Please don't take this personal...but there is no break-in period - for gas mileage... anyway we look at it... for modern internal combustion engines. That situation existed when the metallurgy/material science for some engine components(piston rings, valve stem seals,etc.)were in their infancy.

    Now that the $6.5 BILLION+ per year that GM spends on R&D has solved this problem...we all get the same fuel economy from day one. I've confrmed it by checking it on my first tank fulls...and comparing it to later ones. They really have fixed that
  • eliaselias Member Posts: 2,209
    thanks brudda rspencer! point well taken re the modern gassers not getting improved mpg with break-in - my info re that was out of date - and with my recent gassers i hadn't noticed an mpg improvemen. i figured it was "a leadfoot thing", since my foot gets heavier over the first few thousand miles... do you think diesel cars nowadays are the same? i bet GM has not researched those so much! :(
    the tdi geeks seem convinced that tdi mpg increases over the first few (6?) tens of thousands of miles - and that did seem to be the case for me with a 2003 jetta tdi and 2005 passat tdi - i put about 55k and thought i saw a 10% mpg increase after those miles...
    it's pretty interesting that you were working on oxy fuel processes back in the 70s. cheers & bon weekend & TTFN!
  • rockman59rockman59 Member Posts: 250
    Just drove a little over 1200 miles from Seattle, WA to La Quinta, CA. 2006 Suburban LS 4x4, 3.42 gears, loaded with approximately 800 pounds of furniture. Freeway all the way on I-5. 75mph in Washington, 70 mph in Oregon, and 75 to 80 mph in CA. AC was on about 20% of the time. The computer read 19.6 mpg when I reached La Quinta. I zeroed the computer when I got on the freeway in Seattle and never touched it again until La Quinta. Regular grade Chevron gas was used. Vehicle was in 2 x 4 drive for the trip.
  • duval1duval1 Member Posts: 30
    Have approx. 5000 miles on 07 Tahoe LTZ and am getting 18.5 mostly highway at 70 mph. I'm happy!
  • rspencerrspencer Member Posts: 63
    Good mileage...how do you measure...or calculate your mileage numbers?
  • duval1duval1 Member Posts: 30
    I read the average MPG figure from the onboard computer just before I fill up and I then reset it.
  • sls002sls002 Member Posts: 2,788
    Filling all the way to the gas cap is not a good idea. The fuel tank is vented and the spill over will end up in the charcoal filter.

    For those of you who have noticed, the average MPG that the DIC computes will miss the fuel/vapors that go through the charcoal filter.

    The best way to get accurate MPG results is to fill at the same pump or with the vehicle level. However, averaging a few tankfulls will average out differences in how full the tank is.
  • dardson1dardson1 Member Posts: 696
    06 Tahoe 2wd 5.3 standard axle z71 and getting mostly mid to high 15's around town (miles divided by fuel purchased every tank). I drive conservatively and avoid all the stuff that kills gas milage.
  • ahightowerahightower Member Posts: 539
    2005 Yukon XL, 3.42 gears

    We get about 15 around town, 19 on the highway. I can do slightly better if I'm really trying, but usually I just stay with the flow of traffic.

    I've found keeping the tires properly inflated, even going up a couple PSI from the recommended 32, makes a big difference. The DIC said we got 20.0 mpg on a recent vacation trip of almost exactly 1,000 miles. But doing it by hand, my DIC is usually about 0.5-1.0 mpg overly optimistic.
  • dardson1dardson1 Member Posts: 696
    I'm actually a little more aggressive about milage than I suggested in my post. I keep my tires close to 40 lbs. I doubt it makes that much difference over 35 lbs. (that's the number on my door sticker) but I suspect most people drive around with 2 or 3 low tires which does make a big difference. I don't use drive-up windows unless there is no one in it. I stick to the speed limit and use cruise around town when it's a mile to the next light. I drive like there's a police car behind me. I don't use the AC unless it's hot and never when a trip is too short for it to have an effect.
    For fun (and information) I drove one tank like a teenager just see what would happen. It was fun but milage dropped into the 13's which actually ain't that bad for a 5000 lb.+ vehicle. What I love about these trucks (I've owned 3) is that you can grandpa them around and get minivan milage.
    For the record, last 2 tanks with no AC I got 16+. I'm old enough to remember when 16+ was considered a respectable hwy number. Love my Tahoe, and my trip computer is consistently 0.5 over optimistic.
  • catamcatam Member Posts: 331
    Got back from a road trip to So. Cal. last week.
    Total miles travelled 1555, total fuel used 96 gals, works out to 16.2 MPG for entire trip.
    This is in my 03 Burb, 1500 4x4, 5.3 L with 3.73 gears. (I have LT tires that I keep inflated at 50 PSI).
    I set my cruise at 79mph for nearly the whole trip, and didn't need AC most of the time. I was loaded with my wife, 4 kids, and a weeks worth of vacation gear.
    Not too bad IMHO, I used to do the same trip in a Chev Venture minivan that averaged 26MPG. Unfortunately the Venture wouldn't tow my 6000 lb. boat to the lake in the summer. So we made a change.
  • bk777bk777 Member Posts: 32
    Does any Tahoe owner out there actually get the 17-21 MPG mileage rating on their vehicle?
  • drock4drock4 Member Posts: 1
    Hi arrie,

    Trying to join this discussion..just bought a 03 Suburban and would like to maximize mileage with minimal investment. Can't figure out how to post for all to see...or maybe this is how.

    Anyway, starting to check Cold Air Intake systems $200-$300, that goofy Vortex thing, etc. and power chips. Heard of anything else inside of $500 that makes a significant difference?
  • 73shark73shark Member Posts: 325
    None of the things you mentioned are going to make a "significant" difference in mpg or performance. Chevy does offer performance cat-back exhaust systems and air intake systems.
  • ahightowerahightower Member Posts: 539
    Edmunds had a very good article recently about which tips and tricks actually made a difference in mpg. In summary, inflate your tires and accelerate gently. Also, use cruise control, which I figured went without saying... who wouldn't use cruise control when they can? And don't carry about 300 lbs of crap in the trunk.

    They didn't discuss aftermarket air filters or intakes in that article. I've never had a CAI, but I did upgrade to K&N filters on my last two cars, and noticed more responsive throttle, and about 1 mpg improvement.

    I have a 2005 Yukon XL, and haven't changed the stock air filter yet (going to wait until that indicator tells me to). But I do notice at least 2 mpg difference when I overinflate the tires just a bit (35 psi versus recommended 32), and accelerate gently, keeping the rpm's below 2000 (I have 3.73 gears). In mixed driving, we get about 15 when not trying, and about 18 when really trying. Usually falls somewhere in the middle.

    On the highway, the sweet spot seems to be 65 mph or below. There's a trip we take often where for the first 100 miles the speed limit is 65. Thereafter the speed limit is 70. Starting out, cruise control set right at the limit, I'll see 21 mpg on the trip computer. When the speed limit goes up, I set cruise on 73, then it'll gradually drop to 19.

    Not bad considering it's EPA rated 14/18. (By the way, my trip computer is consistently about 1 mpg optimistic compared to manual calculations done when filling up.)
  • jbm135jbm135 Member Posts: 4
    I saw an article last week that indicated new EPA standard will start for the 2008 model year. They will eliminate some of the ridicules test that are currently used. The current test for city driving is done with modest acceleration and most done at 55 MPH. Yes 55 for city. Highway numbers are done at 65 MPH with almost no acceleration. The new test will include 75 MPH driving with some up to 80 MPH and real world hard acceleration. They are predicted to be up to 30% lower than the current numbers. This won’t help to increase our numbers but at least we won’t fell like we have been duped. That will better match my numbers with my 07 Subdivision.
  • bk777bk777 Member Posts: 32
    That change was forced on the EPA and the auto manufacturers...they got dragged into it by the back of their shirt collars. We would be better off if the EPA got out of the mileage estimate business. They just are not able to deliver realistic and trustworthy information.

    Product performance(non-performance)claims should be handled by the court system.

    Why does it take federal legislative action to correct a product performance claim problem? Why has U.S. EPA not changed it's methods of estimating fuel ecomnomy for 21 years? Why did it take a mandate in the U.S. Energy Policy Act of 2005 to effect change a 2008 model year correction in fuel economy estimates?

    Section 774 of EPACT 2005 instructs the EPA to create new fuel economy measurements that more accurately reflect today’s speed limits, city driving conditions and the use of air conditioning and other fuel depleting features.

    Was it reasonable to use 45 miles per hour as the representative highway speed for testing for 21 years?

    Are city driving conditions in Los Angeles representative of most city driving conditions in our country?

    Do we not use A/C to survive the heat and humidity in places like the south half of the U.S.?

    From te U.S. Senate Committe on Energy and Natural Resources...

    Chairman's statement:

    “The EPA hasn’t updated fuel economy estimates since 1985. We instructed the EPA to update their fuel economy estimates after hearing from frustrated and disappointed consumers who weren’t getting the mileage from their vehicles that advertisements had led them to expect.

    “I consider this provision in the energy bill one of the most potent consumer protections in the bill. It will literally influence how American consumers spend tens of thousands of dollars. Buying a vehicle is one of the most expensive choices a family will make. With gasoline hovering at $2.50 a gallon, fuel economy estimates play a huge role in that choice. I am pleased that the EPA is moving swiftly to implement this provision in the energy bill.”

    The people working at the EPA are well-educated, well-trained and well-paid. I've worked with them. When it takes this much time and effort to correct an obvious problem it's time for change.

    Let your congressman know that you do not trust the EPA...and that they are not getting the job done. Let him or her know that you believe that government is the problem and that you demand change.

    Ronald Reagan had it right...he said it first...GOVERNMENT IS THE PROBLEM.
  • jerrywimerjerrywimer Member Posts: 588
    If you truly want "accurate" estimates, you'll need to be able to test drive every potential vehicle purchase for a full tank yourself. Even if the EPA had specific test runs for every state in the union meant to best replicate how people in that state operate their vehicles, it wouldn't be good enough to be used for courts- everyone drives differently, even if they live in the same area and drive the same roads every day.

    Example- while most people whine about the sticker numbers, I've nearly always been in the ballpark of the numbers on the window for every car I've ever owned. If I try I can also usually beat those numbers. In fact, I recently decided to stop driving my 07 Av conservatively, and went to 5-10 over the speed limits wherever traffic conditions will allow, stopped watching the speedometer too closely, made more sudden accelerations during takeoffs at the few lights I have on my route, pass slower drivers with my foot in it occasionally, all during 30-65 degree temps (morning / evening range). And guess what, in three tanks driven this way, it still got 17.7 mpg as the worst, and 18.8 as the best. Not 20 as on the sticker, but more than close enough that it's easy to see that I'm the biggest differentiating factor.
  • bk777bk777 Member Posts: 32
    It's not about YOU. But you are right on one point. YOU are the biggest differentiating factor.

    And you are on the wrong board...this is the Suburban/Tahoe board.
  • jerrywimerjerrywimer Member Posts: 588
    I hate to break it to you, but I'm most certainly on the right board. And I AM speaking about Tahoes and Suburbans in this case (as well as all other vehicles I've had the pleasure of operating). Sorry if it bothers you to hear something that doesn't jive with your own personal take on life though.
  • bk777bk777 Member Posts: 32
    I hate to butt in on someone else's argument, but in defense of rspencer, GM has spent many 100's of millions of dollars trying to convince American SUV buyers that they will get 17 mpg city and 21 mpg highway with the 2007 Tahoe. The AFM "4 cylinder mode" being part of it. The best I get in my LTZ on the highway is 17.8. My local driving gets me no better than 13.1. Correct me if I'm wrong, but I think rspencer is simply arguing that 13.1/17.8 is not 17/21. Frankly, I agree. I didn't buy the new Tahoe for the gas mileage, but it would be nice if I could at least average what the government and manufacturer claims I will get in all city driving. It's pretty bad when my $48k 2007 Tahoe with whiz-bang AFM technology doesn't get any better mileage than my 12 year old F150 beater.
  • johnny4016johnny4016 Member Posts: 112
    I noticed that you said your tire pressure is set at 50psi? I had mine set there when I first bought my Tahoe Z71. I have 2 Dunlops on the rear and 2 Remington on the front. They are 30570R16. Pretty decent tires. I have lowered my tire psi to 35 psi. I haven't noticed any real change in the mpg. Is there a reason why you keep yours at 50psi? :confuse:
  • greggbostongreggboston Member Posts: 39
    Wondering if anyone out there has had this recall applied (ECM reprogamming) and noticed better gas mileage with their 2007 Tahoe/Suburban with flex fuel engines ? The recall is dated 12/12/06 and GM is calling an "enhancement" (that's engineer-speak for "bug-fix") for FFV (flex fuel vehicles). Just had it applied to our Suburban and the AFM system seems to have been de-sensitized but I haven't been able to do a MPG check yet. Wondering if this is a fix for all the MPG complaints out there.

    Regards,
    - Gregg
    Boston, Mass
  • catamcatam Member Posts: 331
    The quick answer is I don't know.
    FYI, I drop my pressures to 35 PSI in the winter for improved traction in the snow. I know my mileage has dropped (last 2 tanks, 14.6 and 12.4 MPG). But this also coincides with majority of city driving and cold winter temps. I would guess that my mileage has dropped somewhat from the lower pressures, but like I said I don't know.

    The reasons I keep it at 50 during the summer are: hopefully improved mileage, and ride quality when loaded.

    One other point, your tires 305/ 70r16, will likely provide somewhat lower mileage for several reasons.
    1) increased rolling resistance with wider tires.
    2) unless you recalibrated your speedometer, you are actually traveling faster than your speedo states.
  • ahightowerahightower Member Posts: 539
    What's the maximum psi listed on the tire sidewall? 50 seems quite high to me. Isn't the recommended psi about 32? Even if 50 is not exceeding the tires' capacity, it may lead to "capping", where the center of the tread wears more quickly than it should. I used to overinflate the tires on my wife's Geo Metro (I know, not a good comparison), to 44 because that's what the tire said. I should have read the sticker in the doorjamb instead, which recommended somewhere mid-30's as I recall. Discount Tire said they were capping and recommended lowering my pressure. Just throwin' it out there.

    I'm at least interested in what type of mileage difference you are seeing at 50 vs 35. I have a 2005 Yukon XL, with the 17" wheels, and I definitely feel a difference in ride quality at 36 psi vs 30, i.e., stiffer ride except when heavily loaded. Not a major discomfort, and worth the extra couple mpg, but I'm not sure I would want to go any higher and stiffer even if I could.
  • eliaselias Member Posts: 2,209
    imho 50 PSI cold pressure is unwise & unsafe.
    i believe that handling (skidpad, for example) and emergency-stopping-distance will suffer substantially with such an excessive cold pressure.
    additionally you are punishing the vehicle's suspension by pumping the tires beyond what the factory advises - the ride will suffer and the suspension components will wear out more quickly. (tie-rods, center-link, bushings, shocks, springs, for example). imho if you want better MPG, instead of buying a $50k SUV, buy a $30K SUV and a $20k hyper-mpg car, and concentrate the miles onto the car. i realize this is not an option for everyone, but it works for some folks. ttfn!
  • catamcatam Member Posts: 331
    A little explanation.
    My Sub is equipped with LT (Light Truck) tires not P (Passenger car) tires.
    Most LT tires are capable of being inflated to 80PSI.
    This is a very beneficial feature when tires are heavily loaded, (Ie. towing, loaded truck bed, etc.)
    When I tow my boat I inflate my tires to 65 PSI in front, and 70 PSI in the rear. This makes a big difference to vehicle stability when towing especially at freeway speeds.
    (I have towed my boat once at 50 PSI and there is a noticeable difference.)

    As far as the "capping issue" I am aware of the potential for that problem, but I don't expect to see it as the Suburban weighs ~6500# empty. I do frequently examine my tires for signs of abnormal wear or other problems. (Anyone who tows regularly knows the importance of good tires.)

    Like I said in previous post, I know my mileage is currently down with the lower pressures, but how much is from the tires alone is very difficult to say. (Other factors are mostly city driving and cold temps right now.)

    As far as ride quality, I was pleased with the ride at 50 PSI, I notice a slightly smoother ride at 35 PSI, but not enough to change permanently. My wife drives this as her daily driver, and never comments about a change in ride regardless of where I put the pressures.
  • kipkkipk Member Posts: 1,576
    Considering getting a travel trailer in the 3500-4500 pound range.

    Just kind of looking around at what type SUVs are available to perform this task.

    A nephew has a 2004 Tahoe that is absolutely loaded with options, including 5.3L engine. He says his wife gets 15-17 daily driving and he has averaged as high as 28 on the road. But usually only averages 24 or so when maintaining 70 mph or so. Says he re sets the accumulated mileage numbers from the computer before starting the trip. He is in his low 30s of age and tends to drive a tad over the posted speed limits.

    Does this sound reasonable or is he stretching the truth a bit? :confuse:

    Thanks,

    Kip
  • ahightowerahightower Member Posts: 539
    I'd say his wife's numbers are more realistic. There are literally dozens of posts in the forums about real world mpg and towing. Read up.

    I will summarize what I've read over the past few months by saying that even the most optimistic don't claim much more than 20-21 on a good day. Most are right in line with the EPA estimates of 15 city, 19 highway. That's not great, but it's not so bad. Read up in the minivan forums and you'll see most of them don't do a whole lot better.

    And if you need a tow vehicle, almost anyone would recommend a "real SUV" (truck frame) over a minivan or crossover. They may be rated for 4-5000 lbs, but that's the MAX rating which typically excludes the weight of all the passengers, cargo, even fuel. And have you seen a minivan or crossover pulling a heavy load and sagging in the rear? That's gotta really strain the motor, and can't be safe. Better to get a fullsize SUV rated at 7-9,000 lbs and be well within your limits, not approaching the maximum.
  • hsensihsensi Member Posts: 5
    I have been driving my 07 Suburban since March (3,700 miles). I am averaging about 15 mpg, my best ever is 17 mpg. I live in the country so most of my driving is highway. I am a bit disappointed to not get 19 mpg even on a long 8 hour road trip. My current MPG on the computer says 16.2. I am a conservative driver.. slow accelerations and I try to keep my highway speed at 70 mph. My tires are at 35/36 psi.

    Naturally when I purchased this vehicle gas was a little over $2/ gallon. I am a little bummed b/c this is a lease and I will be stuck for 3 years. I love this truck though, it is amazing so I guess that is the payoff.
  • talltreetalltree Member Posts: 2
    I just purchased an 01 suburban and have checked the mileage on the first two tanks. 80% highway miles, 5.3L engine, 3.73 axle, tire pressure at 31 psi: 16 mpg.
    I use regualar gas in all my vehicles with no exception on the suburban, I may be driving over the 65 mph mark more often then I think, I'll pay attention and see if the mileage picks up staying closer to 65 mph.
    My question is this; Has anyone tried switching to one grade of gas or the other to see if mileage changed? And what do most drivers here use? Reg or Super?

    Thanks,
    Tall
  • rockman59rockman59 Member Posts: 250
    Talltree said: And what do most drivers here use? Reg or Super?
    ___________________________________________________________
    Regular. No reason to use anything else.
  • kipkkipk Member Posts: 1,576
    Thanks ahightower!

    I agree a about the full frame. I also believe Rear wheel drives are better for towing.

    And yes, better to have reserve power than to be pushing the limit.

    I recon the nephew is misreading, has a faulty trip computer, or maybe stretching the truth a bit! ;)

    Kip
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