Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!





VW Jetta TDI

1133134136138139155

Comments

  • eliaselias Posts: 1,936
    fwiw, I get my 44 -> 49 mpg with a neutronium-foot - heavier than leadfoot.
    "Drive it like you stole it."
    "Drive the torque".
    I saw that ruking posted on freds forum recently; I bet he'll be back here with some crucial summaries & TDI info.
    my TDI has been parked for weeks; I've only been driving 05 GTO with its new suspension, and the same mpg as a stage 2 EVO .
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 45,272
    edited July 2010
    EPA estimates for the new 2011 TDI are 30 city / 41 hwy, for a combined MPG of about 36. This is probably what people should expect. It does not seem logical that a car would exceed optimum EPA estimates by 25%, although it certainly could in optimal conditions (obviously, "how you drive" is very important).

    It's also a bit lop-sided to say that all VW owner anecdotal reports are accurate and all auto magazine data-logged reports aren't (or vice-versa). This suggests our human tendency to cherry-pick the data as we would like to see it. We need to look at the *best* and the *worst*.

    I personally try to avoid either extreme and just point to EPA data, which, since revisions, has proven to be pretty darn good as a rule.

    If I buy a TDI wagon (and I just might) I would go in expecting no more than 36 MPG average. So the worst that could happen is that I'd get 36, and if I exceeded that, I'd be more than satisifed.

    If I bought the car expecting the 47 mpg reported by Mr. X's blog, as true as it might be for him, I'd probably be disappointed.

    Here are some results I found:

    Motor Trend Longterm ---- 34.9 MPG
    ----------------------------------------------------
    Edmunds Longterm ---

    Best Fuel Economy: 43.0 mpg
    Worst Fuel Economy: 28.0 mpg
    Average Fuel Economy: 34.4 mpg
    -------------------------------------------------------

    Car @ Driver Longterm (39,000 miles) ---- 38 mpg

    ------------------------------------------------------

    Popular Mechanics ---- best ever MPG 45 mpg
    worst ever MPG 25 mpg

    (this averages to 35 mpg)

    -----------------------------------------------------

    Consumer Guide (23,500 miles) 38. 4 MPG

    -----------------------------------------------------

    MODERATOR --Need help with anything? Click on my name!

  • cosmocosmo Posts: 203
    Keep in mind that comparing Jetta TDI models is an apples-oranges exercise. The pre-2005.5 Jetta was a much smaller and lighter vehicle. In 2005.5 the 1.9L engine was upgraded to PD and put out more power to move a larger, roomier, heavier vehicle with a resulting decline in MPG. The current model has a 2.0L engine with common rail that delivers even better performance.
  • eliaselias Posts: 1,936
    Before the EPA changed their "formula", I found their TDI mpg highway numbers to be *exactly correct*.
    49 mpg for my 2003 jetta TDI, for example.
    And exactly 37 mpg for my 2005 passat TDI.
    EPA numbers were *spot on*.

    So it stands to reason that since EPA "lowered" their formula for all vehicles, they would now be substantially under-rating the TDIs which had no problem matching the "old formula" EPA numbers.
  • kyfdxkyfdx Posts: 29,850
    Umm... You are still just one data point...

    You see how that doesn't really, "stands to reason" ?

    MODERATOR
    Prices Paid, Lease Questions, SUVs

  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 45,272
    If that were true, you would have to defend the position that the EPA and all the auto magazines are always wrong, whereas all TDI owners who report an *average* well over 40 mpg, often without presentable evidence, are always correct.

    This sounds more like cherry-picking of data than comprehensive data. One cannot wipe away the auto mag data just because it might not agree with a certain conclusion.

    The longterm tests were for 2009 TDIs by the way---but good point you made.

    You may recall a similar situation occurred when the Prius came out---everyone expected 50+ MPG and most people ended up with 41 MPG.

    Why? Because they did not drive the Prius in conditions that were highly responsive to the best possible MPG. (that is, slow city driving).

    Perhaps those TDI drivers who stay in the torque zone, do not over-rev, use cruise control, live at sea level, etc., will consistently beat EPA while the less skillful or geographically challenged (with weather or traffic) will never even meeet EPA.

    MODERATOR --Need help with anything? Click on my name!

  • moparbadmoparbad Posts: 3,842
    Add me to the list of obtaining the mpg or exceeding it by a small margin with the old formula (and older TDI models) and right now with a 09 Jetta TDI DSG I obtain 40 mpg average in suburban driving and on highway for a trip 48 to 50 mpg is my typical result.

    Exceeding mpg for the new EPA formula is more the rule and not the exception for TDI.

    For those struggling with mpg, short trips in the TDI decrease average mpg significantly.
  • bpeeblesbpeebles Posts: 4,085
    edited July 2010
    You said "For those struggling with mpg, short trips in the TDI decrease average mpg significantly."

    Very good point! A cold engine gets poor MPG and the TDI takes about 3x longer than a gasser to get up to operating temp. (Engine computer will inject xtra fuel until engine comes up to operating temp.)

    Reciently, I was getting less than 700 miles per tank of fuel.... It turned out the ETS (Engine Temparture Sensor) had gone bad and was reporting to the engine-computer that the engine was always 'cold'. Hence, the computer was injecting too much fuel all the time.

    BTW: I have ALWAYS been able to beat the EPA estamates on EVERY vehicle I have ever owned! (even motorcycles) I look at the EPA estamates as the very LOW end of what I should expect for MPG.
  • m6userm6user Posts: 3,017
    And you can read in just about every forum of people not being able to even get the EPA numbers. What does that tell you? Maybe you're not an average driver. Maybe you really, really mind your MPGs so to speak. I think the EPA and most of the auto mags try to give an ESTIMATE of what the average driver can expect. The people that post here regularly and keep track of every gallon of fuel they use over years of ownership could hardly be called average. Who does that?
  • sebring95sebring95 Posts: 3,233
    I think it's clear there are certain models that clearly manipulate the EPA testing data. Usually it's with the EPA process overestimating mileage on hybrid and multi-cylinder engines (my '05 Odyssey has a EPA sticker laughingly stating 28mpg....). They seem to have improved on this as the 2010 Odyssey is rated 25mpg...which I still have never hit but I digress.

    Considering the efficiency of the TDI at straight-on highway speeds it's easy to understand in my mind how beating an EPA number wouldn't be hard. In most every gas vehicle I've owned I tend to hit or beat the EPA highway number (the Odyssey being the exception) even running 70-75mph. The EPA tests for highway is at a lower speed for a shorter distance but also includes some non-typical long highway attributes like several bursts of WOT and 80mph legs with an overall average speed of 48mph. I had no trouble beating EPA numbers on my Jetta and I drove the snot out of it.
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 45,272
    Keep in mind that EPA numbers were revised *downward* last year---you might remember the great distress this caused automakers.

    Once again, the auto mags logged their averages over many tens of thousands of miles, and *average* means that you clip off the edges of the bell curve in the data points---so those of you getting 25 mpg or 45 mpg are thrown out of the *average*.

    Also EPA does various testing cycles, some of which are not under ideal conditions for economy.

    I only bring this up so that some TDI future buyers are not disappointed by getting "only" 36 MPG. That's what you're supposed to get. If you get more, well, good on ya'.

    MODERATOR --Need help with anything? Click on my name!

  • eliaselias Posts: 1,936
    stands to reason , yes. My one data point is replicated tens of thousands of times by other TDI owners. Believe what you like! Or step up and drive a TDI and discover the truth yourself. You too will be just one more datapoint getting better mpg than EPA tests indicate.
  • 104wb104wb Posts: 38
    I looked into the new ratings a little bit when they came out, 2008MY I think? Previously, EPA fuel economy numbers were based on two fundamental test cycles which hadn't changed in many years (although adjustments had been made to the raw results, hence EPA 'adjusted' mileage). The new ratings were devised to include tests that represented more aggressive driving behavior / conditions. These three extra tests were adopted from the emissions side of the business. One of these added tests was a 'cold start / operating condition' test which diesel powered vehicles had never had to participate in on the emissions side, and so that data was perhaps not readily available to calculate the new EPA rating for 2008MY, maybe 2009MY Diesels. Transitionally, the EPA allowed any car to have the new rating based on the two original, traditional test cycles, modified by a new EPA formula that was based on empirical data from about 100 different cars, all but a couple of which were gasoline powered. Since there are some fundamental differences between how gasoline engines operate (normally stoichiometric, but 'extra' fuel added near full load or high speed or cold start - aggressive situations) and how diesel engines operate (always globally lean), it is quite possible that diesels opting to use the EPA formula instead of running all five tests might end up with a lower rating. I think by now, 2011MY, that the transition period would be over, but I'm not sure about that. It would be in the manufacturers best interest to post the best numbers possible, which would mean using all 5 tests, not the EPA formula based on a fleet of gasoline powered vehicles.

    My observation, based on 'estimates of drivers like you' on the EPA website, is that the average mpg for all diesel powered cars - VW, BMW, MB, Jeep - run closer to the 'hwy' rating than the 'avg' rating. Averages for gasoline powered cars are usually pretty close to the advertised 'average'.
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 45,272
    edited July 2010
    I'm more inclined to believe the longterm auto magazine testing as more representative of real world averages. So many reports from all over the world can't be all wrong. That makes no sense. I can post from Canada, Australia and Europe but I'm not inclined to belabor the point.

    If it matters, a VW JSW forum seems to verify the 35-42 range as average.

    http://forums.tdiclub.com/showthread.php?t=260851

    The mags also verify that their averages are closer to EPA hwy than EPA city, so really, both sides of the argument have their points.

    MODERATOR --Need help with anything? Click on my name!

  • eliaselias Posts: 1,936
    fwiw all my personal data/experience with ~500k miles on 4 TDIs is with 2006 & prior TDI models. two were manual, one was slushbox, one was DSG.

    It's pretty clear both from the EPA as well as anecdotal reports that the 2009/2010 models get slightly lower mpg then the 06s & earlier - maybe because so few are broken-in yet.
    Or maybe because the newer models will never get as great EPA-highway-matching mpg as do the 2006 & prior models...
    best regards...
  • gagricegagrice San DiegoPosts: 29,052
    Don't forget the 2009 Jetta TDI is the mileage champ according to the Guiness Book of World records. So far no challenges including the Prius.

    Mr. Taylor and his wife, Helen, had completed a 48-state drive averaging 67.9 miles a gallon: 9,505 miles in 19 days, filling up only 13 times and spending a total of $371.03 for diesel fuel. That beat the Guinness record of 58.8 miles a gallon they set a year ago on nearly the same route in an almost identical 2009 Jetta TDI.

    One difference this time was the tires. The Jetta was fitted with Goodyear Assurance Fuel Max tires, low-rolling-resistance models that will be standard equipment on the 2011 Chevrolet Volt.


    http://www.nytimes.com/2009/09/13/automobiles/13MILEAGE.html

    They doubled the EPA estimate. Has any other vehicle come even close?
  • m6userm6user Posts: 3,017
    edited July 2010
    I saw a test of the new Hyundai Sonata that was done by a bunch of press types out in CA when the new model just came out. They were challenged to drive a certain route and get the best mpg they could. Excerpt follows:

    First place went to the team of Donald Buffamanti of AutoSpies and Jaime Florez of Ruedas ESPN with a 52.8 mpg rating that would even impress a Prius.

    The gold medal winners got more than just praise, however, as Hyundai Motor America CEO John Krafcik offered to treat anyone who could beat his personal time of 47.8 mpg to a private dinner.


    This is on a car that has an EPA average of 28mpg I think. They almost doubled the EPA average of 28mpg. However, when you consider that D2 is about 5-10%(my area is at 8% higher right now) higher price than reg. gas it is pretty much a wash in performance and cost.

    However, nobody drives anything close to like any of these people did on a normal basis so, while it's it's interesting, it doesn't mean a whole hell of a lot.
  • altair4altair4 Posts: 1,469
    I've been following this thread because of my interest in possibly purchasing a JSW TDI in the future. But I felt compelled to post a reply about the EPA mileage numbers. Currently, I'm driving a VW Paswsat, 1.8T, with the 5 speed tiptronic slushbox.

    The original EPA sticker gave the figures as 21 City, 25 Combined, and 30 Highway. The new formula gives the results as 19 City, 22 Combined, 28 Highway.

    I keep obsessive compulsive track of my mileage: over 75,000 miles, I've averaged 22.94, so I'm right on the new combined average. Highway trips, ranging anywhere from 200 to 425 miles, usually exceed 30 mpg. My record is 34.9 mpg across northern Ohio. This is all without any hypermiling techniques, and I'm usually 5 over the posted speed limit, and with the a/c running. So I see the EPA results for Highway as underestimated. City driving all depends on time of day, and traffic. Off-peak (non rush hour) is around 20. But stop and go in heavy traffic really kills the mileage with the turbo - I can easily dip to 17 mpg.
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 45,272
    These are obviously hypermilers. This has little relation to 99% of all drivers. I could coast, short-shift, over-inflate tires, pick my routes, etc. and easily break EPA for my car, every time.

    MODERATOR --Need help with anything? Click on my name!

  • dwpcdwpc Posts: 159
    I'm a moderate driver. I don't leadfoot it, but neither do I lag traffic or baby the throttle. I'm getting 35-37 MPG on So Cal freeways and around 30 running to the mall and local driving. On long trips at 70-75 mph, I can get the avg close to 40. For anything more, I'd have to change my pretty normal driving habits radically. The only way I can get above 50 mpg for any period is to drive under 50 mph on a dead flat road. Even with cruise control, the slightest grade will cause the real-time mileage readout to plummet. Idling at stops lights has devastating effect on it. I can't drive that way. I know mileage will improve as the engine wears in over the first year, but its not 20%.

    Hypermilers show the economy potential for the TDI, but I think the way the TDI forums throw 50 mpg around is misleading and raises expectations of buyers unreasonably. The best thing about my JSW is that it get near or better than 40 mpg while giving sports car performance and pretty close to luxury sedan comfort.
  • asaasa Posts: 359
    edited July 2010
    I think one distinction with the '09+ TDIs that often gets lost in MPG discussions is that the car delivers excellent fuel ecomomy even with spirited driving. Other cars require driver compulsivity to achieve high fuel economy, but a driver can put the spurs to the new TDIs (with 140 HP and 236 LB/FT) and still be pleased at the pump. That's a rare and welcome combination.

    My wife and I are most ofen conservative drivers and our new (4000 Miles) '10 JSW 6M delivers 30 to 32 MPG in city driving and 43 to 47 MPG on the Interstate at 70 MPH. We are very pleased at the economy, appearance and sportiness of the car.
  • m6userm6user Posts: 3,017
    Uh, I thought I pretty much explained that this was a challenge to a bunch of auto writers to see who could get the best mpg over a certain course. Yeah, most of them went about about 30--35 mph. That's why I said nobody drives like that, it doesn't mean a whole hell of a lot but it's kind of interesting.

    Did my post sound like I was trying to say the Sonata gets that kind of MPG on average or something? I think it was pretty clear that I was not. I was just responding to the post about the couple that takes a TDI across country and got about double the EPA avg. 99% of people don't drive like that either. I was just trying to point out that by using all those tricks there are other cars out there capable of hitting some big mpg numbers besides the TDI if driven really, really conservatively.

    And yes, the TDI would probably still beat any car out there on an average mpg basis if driven correctly but just not by as much as some people would like to think.
  • bpeeblesbpeebles Posts: 4,085
    Mr Shiftright.... "coasting" actually REDUCES MPG.... let me try to explain it to you.

    First, you need to understand that all modern fuel-injected engines actually CUT OFF the injection of fuel anytime the engine is in overrun.

    Knowing this...If you were to go down a long hill (several miles)

    1) Allowing the engine to idle (coasting)...then the engine would be consuming fuel keeping itself idling

    2) Same hill, leave engine in high gear - foot off throttle, The engine-computer will cut all fuel-injection thus consuming NO FUEL AT ALL!

    Having an understanding of how the fuel-injection works helps alot. Hence, I keep my engine in gear AS LONG AS POSSIBLE as I approach a stop... pressing the clutch at the very last moment. This consumes the least amount of fuel.

    --------------------
    Also, you seem to use the term "hypermilers" in a derogatory way. Instead, I feel the techniques should be taught in driving schools. Many of the techniques which increase MPG also add SAFETY... Like always looking forward to anticipate a stop and get off the throttle early.

    I keep 40 PSI in my tires and short-shift as much as possible, think-thru my route to minimize road-time. (in your nomenclature - "Pick my routes")

    I do not consider this "hyper mile" driving. Instead, I have trained myself to drive as efficently as possible. It is second-nature to me (and my wife...since she drives the TDI more than I do so I cannot take credit for the high MPG)
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 45,272
    Actually coasting probably does increase mileage because most people don't leave a car in gear without touching the gas going down slight grades---you'd slow down too much for the traffic behind you, so probably in the 'real world' the choice is between coasting vs. light pedal pressure in gear. You can go faster coasting downhill than you can by staying in gear with no gas pedal.

    I don't regard "hypermilers" as a derogatory term, but rather as an experimental exercise that isn't very practical in the real world. I often play with this myself just to "see how much I can get".

    Sounds like you are referring to common sense driving, which I'm totally in agreement with.

    MODERATOR --Need help with anything? Click on my name!

  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 45,272
    edited July 2010
    Your theory is right, but actually, in real life, coasting probably does increase mileage because most people don't leave a car in gear without touching the gas going down slight grades---you'd slow down too much for the traffic behind you, so probably in the 'real world' the choice is between coasting vs. light pedal pressure in gear. You can go faster coasting downhill than you can by staying in gear with no gas pedal.

    I don't regard "hypermilers" as a derogatory term, but rather as an experimental exercise that isn't very practical in the real world. I often play with this myself just to "see how much I can get".

    Sounds like you are referring to common sense driving, which I'm totally in agreement with.

    MODERATOR --Need help with anything? Click on my name!

  • ggeeooggeeoo Posts: 94
    You are so right what a difference at 60 years old I have owned many cars this VW
    TDI Sportswagon is great. Tight parking space no problem even when the guy behind
    you left six inches to spare. MPG 50 easily 3/4 of a tank from Newport Beach CA to
    Phoenix AZ. AC cold and forceful back and front seats.
  • asaasa Posts: 359
    edited July 2010
    Tight parking space no problem even when the guy behind you left six inches to spare.

    When we shopped for our new car, I carefully studied cargo capacity and exterior dimensions because we too dislike large vehicles. I was amazed at the number of SUVs and crossovers that are significantly larger in exterior dimension than the Jetta Sportwagen, yet offered significantly less cargo space behind the rear seat! In my analysis, it seemed that only Subaru and Volkswagen knew how to design an efficient interior and not bloat the exterior.
  • cosmocosmo Posts: 203
    Check your state laws. In most states, coasting out of gear is illegal because the driver is not in full control of the vehicle. If coasting was legal, safe, and increased fuel mileage, don't you think the manufacturers would have re-introduced the freewheeling overdrives of the 50's and early 60's? Maybe you should research Car Talk and learn what the real experts, the Tappet Brothers, think of coasting. ;)
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 45,272
    I would hardly call the Tappet Brothers "experts" at much besides laughing at their own jokes :P

    All I said was that you can coast faster downhill in neutral than you can coast in gear with no gas applied----this is undoubtedly true, but I'm not RECOMMENDING it for gosh sakes! :shades:

    If you're like me, you don't have time to play hypermiler games. I need to get where I'm going, to drive "normally" like I always do, and hopefully, to get the best possible MPG while doing it.

    MODERATOR --Need help with anything? Click on my name!

  • bpeeblesbpeebles Posts: 4,085
    edited July 2010
    Have you even driven a diesel engine? ..... Since there is no throttle-plate, there is extremely little decelleration when foot is off the throttle. (almost none at all) A diesel engine is always allowed to breathe as much air as it wants.... hence, the only decelleration forces are the friction of the bearings, cams against the valvesprings, and rings scraping the cylinder-walls.

    With a diesel engine, it is very easy to have the engine in 'overrun' while going down a long hill. This is one of the many reasons that a diesel engine is inherently efficent.

    Contrary to what some folks will tell you, it is NOT the compression-ratio of an engine which causes decelleration forces. Technically, the force it takes to compress during piston upstroke is nearly identical to the force returned when the piston is on the downstroke. This cancells out the compression-ratio altogether. (Newtons laws in action)

    Instead, It is mostly the closed throttle-plate causing engine to pull a very high vacuum against it. (Gasoline engine has this inherent defect which reduces MPG)
Sign In or Register to comment.