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Thread: VW Golf TDI and biodiesel

  1. #11
    Join Date
    Dec 2007
    Location
    Lake Macquarie (just south of Newcastle) NSW
    Posts
    1,363

    Re: VW Golf TDI and biodiesel

    Quote Originally Posted by John K View Post
    Now I am wondering if this system can be easily removed, restoring the ability to use bio?
    I suppose removing it would invalidate the warranty. Bugger.
    Cheers,
    John K
    You might find that removing the system is illegal. It may be fitted to make the engine comply with emission requirements.
    In the early 70's petrol engine vehicles in Aust started being fitted with emission control systems and it was illegal (although common) to remove, disconnect or disable them. Then in 1985 unleaded petrol was introduced to allow the use use of catalytic converters (not to reduce the lead emissions to the atmosphere) as the lead coats the catalyst and disables it resulting in increased HC and CO emissions (no effect on Nox as it is controlled by EGR).
    Since 1985 it has been illegal to a) remove the catalytic converter, b) operate a vehicle with an inoperative catalytic converter, c) use leaded petrol in a post '85 vehicle.
    I am well out of touch with the current situation as I left the industry in '98 so I may be well off regarding diesel particulate filters but I imagine that if biodiesel use can disable the particulate filter and the filter is required by law then it may be technically illegal to use bio in a vehicle so equipped.
    Of course it may be unenforceable but I would not suggest that anyone should break a law just because it is unenforceable.

    I do wonder about these new engines with electronic control of the injection.
    In petrol engines the exhaust gas composition is sensed and input to the control computer to influence the injection. If this is done on the new tech diesels then perhaps the different exhaust composition from high ratios of bio could alter the injection control. If so I imagine it would be a relatively simple matter for the right person to alter the programing of the control computer to suit bio but then it would not suit petro-diesel - problems, problems!
    Then I wonder about these same engines on SVO. Even greater difference in exhaust gas composition and with a 2 tank system the need to be able to run properly on both Veg and diesel.
    I am pleased to have a 1998 model diesel.

  2. #12
    Join Date
    Dec 2007
    Location
    Mayshill NSW.
    Posts
    26

    Re: VW Golf TDI and biodiesel

    In regards to manufacturers; I called Holden to check their policy on BIO.BUt read a few stuff on the forum before so was informed a bit. So I spoke to this person and asked whats the policy with bio. He was totally negative towards it and sayign some jive about it leaves junk in the engine(We all know why's that) and damages lines (). Anyway i asked him about the new ULSD(ultra low sulfur diesel) he didn't know what that was. I told him its the standard diesel and like bio it affects the lines too (causes swelling instead of shrinkage like bio) and that its everywhere.So if you can't use bio, why is it we can use ULSD. He said, after checking, that we shouldn't use ULSD (). Hahahahahhahahahaha thats the industry and governmental standard now and most places you go has it (since pre 2004). In short they don't know much and where down right insulting.
    alex

  3. #13
    Join Date
    Jan 2007
    Location
    Cambridge, UK
    Posts
    9

    Re: VW Golf TDI and biodiesel

    The mian issue with biodiesel in new VW's (and any other make) with DPF's is Post injection of fuel to clear the DPF. When the fuel enters the cylinder some unburnt fuel is passed through to engine lubricating oil. This happens all the time with egines burning diesel but more so with FAME/RME being denser. Petrolium diesel will evaporate over time but biodiesel does not.
    Biodiesel oxidises in the engine oil and effects metals found in bearings etc this leads to engine wear. Increasing levels of sump oil can also lead to problems.

    Regular oil changes and minimising short journeys may help to lower the effect.

    Uncle Slabs
    Vauxhall Combo 1.7d non heated filter, using HDUCOME B50-B100. Bodywork mods: Rust & dents!

  4. #14
    Join Date
    May 2006
    Location
    Adelaide Hills
    Posts
    98

    Re: VW Golf TDI and biodiesel

    Quote Originally Posted by slabster View Post
    The main issue with biodiesel in new VW's (and any other make) with DPF's is Post injection of fuel to clear the DPF. When the fuel enters the cylinder some unburnt fuel is passed through to engine lubricating oil. This happens all the time with egines burning diesel but more so with FAME/RME being denser. Petrolium diesel will evaporate over time but biodiesel does not.
    Biodiesel oxidises in the engine oil and effects metals found in bearings etc this leads to engine wear. Increasing levels of sump oil can also lead to problems.

    Regular oil changes and minimising short journeys may help to lower the effect.

    Uncle Slabs
    Slabster have you experienced this?
    Evaporation of fuel has little to do with density.
    Water is much denser than Diesel or Biodiesel but will boil out of the engine oil at 100 C.
    Diesel and Biodiesel boil over a range of temperatures.
    This is measured in a laboratory as Initial Boiling Point (IBP) and Final Boiling Point (FBP).
    The Final Boiling Point of both fuels is well above the engine oil temperature during normal operation and therefore any Diesel or Biodiesel passing into the sump will stay there.
    What about piston ring?
    Aren't they supposed to stop fuels entering the sump?
    I have never seen a rise in my engine oil and I now have done 42,000 Km on 100% Biodiesel in our VW Caddy with the 1.9L TDI engine.
    It runs like a dream on home made Biodiesel.
    Last edited by DutchAussie; 24th October 2010 at 06:46 PM. Reason: Spelling
    Regards,

    Arie (DutchAussie)
    2007 VW Caddy 1.9 L TDI with DSG

    Australian VW Caddy Website:
    http://vw-caddy.yolasite.com

    Australian VW Caddy Forum:
    http://www.getphpbb.com/phpbb/index.php?mforum=d

    Australian Biodiesel Handbook:
    http://www.biodiesel-handbook.yolasite.com

  5. #15
    Join Date
    Feb 2007
    Location
    Natone, Tasmania
    Posts
    78

    Re: VW Golf TDI and biodiesel

    My wife got sick of my old jap import diesel sedans 'always one in pieces in the shed'. Well this isn't really true, but she got herself a 05 caddy TDi (pumpeduse) when I was away which would never be any trouble. The first came as a plaintive call from Sydney, due for the 120 thousand k service.
    "VW wants $2400 to do this. Will you do it?" I reminded her that I don't usually spend that much when I buy a car.
    "F(*& right I'll do it." Anyway it went well on BD 50 for a couple weeks while I organized timing belt etc. And with the valve cover off checked out the camshaft. This turned out to have some damage still at an early stage. PD engines do that apparently. Wade Camshafts in Melbourne fixed that, ground a couple lobes, cleaned copper smeared bearing journals, Rockwell tested the ground lobes(OK) all for $190 including freight. Four black lifters, bearings, seals, single use stretch bearing cap bolts etc. (VW, I couldn't find aftermarket stuff in Australia another $500 or so). So it is going back together ok but the camshaft is stiff. If it seizes I lose all so I am having a glorified bearing scraper made - a polished shaft exactly the same size as the bearing journals with a longitudinal slot machined down the length and one corner ground away, slightly to begin with to just touch the high points on the bearings until the cam turns freely. You can't torque the new bolts all the way by the way until you are happy.
    Anyway biofuel was another potential problem and it has to do with the DPF which I find works like this: it catches soot and if you are running longish hot runs it burns it out as you go. But if you are doing short runs around town it doesn't and the pressure on both sides of the DPF unit is monitored by the computer. At a certain threshold the vehicle goes into a burnout mode in which fuel is injected during the exhaust stroke and here is where you get into strife - the higher viscosity of bio means unburnt fuel tends to stick to the cylinder wall and ends up in your sump where it dilutes your oil and destroys its properties making the pumpe duse cam with its ridiculous little thin lobes even more likely to raise hell with the lifters. Synthetic oils are not affected anywhere near the way ordinary oils are.
    My neighbouring VW enthusiast who sold my wife on these things tells me my caddy doesn't even have DPF in which case the only other variation from Euroland for bio is a more resistant rubber connector in the fuel tank inlet.
    IF I have one I would consider destroying it - pushing a rod through all that ceramic and platinum group metal crap and getting rid of it so there will never BE any monitored back pressure differential - this so and so owes me too much not to run on biodiesel. However do your own research rather than doing anything stupid on my say so.

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