2010 Golf TDI blog and observations

Discussion in 'Diesel powered automobiles' started by seftonm, May 5, 2010.

  1. seftonm

    seftonm Veteran Staff Member

    I figured I'd make a blog of what I'm learning and discovering with my new car.

    -Fuel economy at 60+ mph on cruise is very close to that of my old TDI. When this one breaks in, it may beat the old one in certain cases. Haven't been able to get city fuel economy close yet. While my old one would easily break into the mid 3 L/100km range, it's been hard to get this one below 4 L/100km so far. Granted, I haven't done much city driving so it may improve a little.

    -I'm starting to detect some of the engine's transitions in operating modes to do regenerations and so on. It's not as seamless as in the Sportwagen we drove, possibly because there's less weight to smooth things out? The best analogy I can think of is that it feels a little like when the engine fires up when accelerating in a 2nd generation Prius, which means most passengers will probably never notice.

    -I miss my Euro spec headlights! These ones aren't too bad, the low beams could maybe use adjusting up just a little. High beams are pretty good, especially for halogens.

    -Cabin isolation is very good. It's a very quiet car at highway speeds.

    -Great gearing. Every gear seems to have a purpose, unlike some close ratio boxes. 5th is taller than my old 5th, and 6th is even beyond that. 60mph is about 1600rpm in top gear now, compared to about 2000 before.

    -MFD average so far says 45mpg for this tank. No clue how accurate it is yet. Jettas are usually pretty close to accurate. I'm hoping my car is too.

    -Scangauge is useless. Can't display coolant temp or boost, and fuel economy seems way off. Seems like the LOD number is messed up and that's throwing fuel economy off.

    More to come as I learn more.
  2. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Super Moderator Staff Member

    Nice. (1800rpm - 1900rpm in our Civic)
  3. WriConsult

    WriConsult Super Moderator

    :eek: Wow! Even the 2000-ish rpm of our older Mk4 TDIs are lower than any other MT I've driven in many years.
  4. bestmapman

    bestmapman Fighting untruth and misinformation

    Hey Mike, you may still be able to swap out the 5th gear for a taller one. I seriously considered that for my former Jetta.
  5. PaleMelanesian

    PaleMelanesian Beat the System Staff Member

    Wow again on the gears! I'm running 2500 at 60, and I know some are even worse. Honda Fit, I believe, is pushing 3000 rpm.
  6. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    That's better than my ridiculously geared Insight. :)
  7. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Mike:

    ___Have you made it through your first tank yet?

    ___Good Luck

  8. seftonm

    seftonm Veteran Staff Member

    Hi Wayne, I think I still have 2/3 of a tank left. Turns out I'm carpooling most days so it only gets driven once or twice a week.
  9. seftonm

    seftonm Veteran Staff Member

    Just passed 1000km on the odometer. Still have about 1/4 tank left, will probably end up burning through the rest of it this week.

    Got the ScanGauge cable routed and installed today. There's not much useful information that I can pull up with it yet, right now I'm limited to water temperature, volts, and that's about it. I'm afraid this car is going to become a black hole for my money. The list of things I want to do with it keeps growing. Next weekend, I'm installing a trailer hitch so that I can carry pedal bikes and / or tow the motorcycle. Windows could probably use tinting, too.

    Other random observations:
    • MFD still says about 45 mpg. Fuel economy on more recent trips seems to have improved a little.
    • Interior space is good overall for a car this size. I just wish there were a few more storage compartments.
    • Being the early adopter for an uncommon model makes finding parts and how-tos hard to find. Haven't been able to find a source for oil filters or oil yet other than the dealer. Americans get free maintenance on their VWs but we do not.
    • Nice seats. Better side bolstering than what I remember from the Jetta. The seats seem to be somewhere between the regular Jetta's seats and the sportier GTI ones. The rear seats are also reasonably comfortable.
  10. seftonm

    seftonm Veteran Staff Member

    First fill. 958.1km on 48.52L for 5.1L/100km or 46.4mpg. MFD said 5.2L/100km. Windows have been tinted and hitch is now installed, but something's up with the trailer wiring harness and I can't figure out what :mad: Brake lights aren't working correctly for some unknown reason. I've rechecked wiring multiple times so I think either the controller is defective or it's not the right one for my car. The tint seems to make a significant difference in cabin temperature when in the sun.

    Been watching the Scangauge more often recently and it looks like it'll be impossible to get an accurate mpg reading out of it. MPG seems to be derived from LOD somehow, and LOD simply isn't an accurate representation of the fuel flow rate in this car. I don't know how LOD is calculated, but it just loves to hover around 60-70 regardless of what I'm doing. Then I noticed today that the car was going through a DPF regen on the highway and LOD dropped to around 40 for that period. I'm wondering if the EGR rates somehow affect LOD calculation. The engine runs a lot of EGR whenever possible to keep NOx down, but drops it significantly when doing a regen to bump up combustion temperatures. If that's what's really going on then I'm honestly amazed at how much that system is being used. Accelerating or steady state, LOD is always in the 60-70 range except for that regen. It's as if the ECU's primary concern at all times is keeping emissions in check, which I guess makes sense. But it makes me wonder how many more MPG a Euro spec engine would be worth with less concern about the NOx.
  11. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Interesting. That tank average isn't far off of what you averaged in your other Golf... think you can bring it up substantially? How long does it take for a diesel to "break in" anyway?
  12. seftonm

    seftonm Veteran Staff Member

    Hi Sean, most of the break in is done after 10k miles. After that, things keep slowly improving for another 50k or so but the difference during that period is much less significant than the first 10k.

    Above 50 or so mph, this car will go toe to toe with my old one unless advanced techniques are used. I'm thinking the gearing may even give it an advantage at high (75+ mph) speeds. This car seems like it will just eat up high speed highways miles. Around the city is where it gets killed. Idle fuel consumption is about 50% higher than my old car, and it's a total pig for the first mile or two of most trips where it's probably burning extra fuel to bring the DOC and DPF up to temperature.

    I'm sure the average will be improving and beating my old car's average as time progresses. I'm a little restricted in what techniques I try to apply during the daily commute because the car's often filled with 2-3 co workers who want to get to work and back home at their usual times, and I try to keep cabin temperatures more reasonable for them. The flip side is that I only need to drive 1-2 times a week though so I'm quite content with that arrangement.
  13. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    50% higher idle consumption?!? :eek:
  14. seftonm

    seftonm Veteran Staff Member

    Yup. My old car was around 0.4L/h. The new one's 0.6-0.7L/h. I'm wondering if that will come down as it breaks in, I recall it being even higher a few weeks ago.
  15. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Wow. How are you measuring this if the ScanGauge is hopelessly off? NICE-ON coasting monitoring of built-in FCD?
  16. seftonm

    seftonm Veteran Staff Member

    Yeah, I can calculate it back from the NICE-on coasting. Also, if I'm idling below about 3 km/h the iFCD will switch to L/h instead of L/100km.
  17. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    That's a neat feature!
  18. seftonm

    seftonm Veteran Staff Member

    A couple pictures with the newly done tint and hitch.

  19. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Very nice! That's a slick vehicle, Mike. :flag:
  20. msantos

    msantos Eco Accelerometrist

    Hi Mike;

    I wholeheartedly second what Sean said! VEEERY nice :D

    BTW: 0.5 to .07 resembles the idling consumption rates for a gasoline engine. I agree, that is not typical of the frugal idling rates diesels are known for, but then again, there must be a good reason for that. Could it be another emissions related attribute?



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