Hi all,
I read through all that material available on the link below. While it didnt overly enthuase me, I have to compliment them on the realistic analysis of the subject - they are not sugarcoating it for potential customers.
What I took from the info (mostly from the Elsbett site - the firm who make the conversion kits and the most "technical" analysis) was:
1. The sites seem to deal with Pure Plant Oil "PPO" (what Great Gas would sell you on the forecourt) - also seems to be described as "SVO" meaning straight vegetable oil. I gather this is different from "Bio-Diesel" or RME which Heinblood describes below. Is "bio fuel" a word at all, & if it is what does it describe?? I wish they could standardise the names a bit - me get confused.
2. A conversion kit is necessary for running on 100% Pure Plant Oil (I gather that most modern diesels - especially German manufactured - should be able to run unconverted on, say, a 5% biofuel mix.) Kit costs about €850 to €1,200 per the German site, before delivery. Irish sites say factor in about €1,650 + VAT for, I think, fitted conversion.
You can still run a converted car on 100% petro diesel all the time if you want - could be relevant re resale. - I wonder is there any hoping of taking the kit with you to your new model???
3. The problems seem to be a) fuel has higher viscosity - less "runny" - means that if not treated then could clog glow plugs etc, b) may not burn completely if engine not at full temperature or not at "full load" - I'm not quite sure what "full load" means but I expect it means where the car is only ticking over and only a small fuel charge is injected into the combustion chamber, c) fuel storage could be problematic in cold weather, d) various acids may be produced as a by-product - this is why German diesels may be more suitable since this acid issue already arises to some extent due to the fuel mix on sale in Germany, e) there can be possible contamination of the engine lubricant oil.
4. There are some solutions to the above problems but it isnt exactly clear how well they fix the problem. The solutions deal mainly with a) heating the biofuel and adjusting the injector timing - the conversion kits deal with the heating etc, b) operating a 2 tank system where you start on petro diesel, then switch over to PPO once you are heated up, and before you shut down for the night you swap over to petrodiesel to "clean out" the system again, c) add "winter diesel" to your storage tank (which you will almost certainly need) to stop the cold from affecting it, d) using vegetable based engine lubricant oil or just changing the oil more regularly.
5. It seems increased engine wear can be a problem (despite the engine running at lower temperature). The "paper" produced for Shanghai conference (also on Elsbett site) talks about increased engine wear after 10 hours. It isnt clear if recent modifications have overcome this - and unless you are an international trucker I guess you're never going to drive 10 hours straight - & I presume thats against trucker regulations as well.
6. Before going for a conversion it says your car must be in very good nick - & interestingly it says one of the ways in which you car mightnt be in suitable condition is where it has run on biodiesel before ..... (in fairness I presume the conversion kit should/does take away most or all of the negative wear implications).
7. Apart from the 2 tank system mentioned above, you can have a 1 tank system where, I gather, you are 100% PPO all the way. When I checked for my car it was recommending a 2 tank system.
8. The major drawback seems to me to be the requirement in many cases for a 2 tank system, & it recommends 20 miles before switch to biodiesel. So you would want to be doing fairly serious miles every day to make it worthwhile. Maybe this leads us back to the old wisdom that you needed to be doing serious miles anyway to make diesel worthwhile - but diesel now has a slightly more "environmentally friendly" tag and some people just like 'em (like myself).
9.The other drawback, and again its not clear how well this has been solved by the conversion kit is that the PPO car doesnt seem to do too well when not at "full load" - which I take to mean idling or at low rev. Doesnt this rule out a lot of our urbanites ??
10. As an interesting aside the Elsbett engine, which is specifically designed for PPO, doesnt require any coolant system because it runs at lower heat.
So in summary I'm a wee bit deflated that the news is either a bit mixed or just not clear, and that a recommended 2 tank system for my car doesnt seem to make sense for me as not doing the requisite miles. I'm hoping someone will convince me otherwise !!
I'd say its when the major manufacturers start making PPO engines that the revolution will really take off - you can expect most of the above problems to get sorted more satisfactorily. Other things to consider is what "age" of car to convert - presumably you wouldnt modify a new car as more than likely would negate the warrunty, and once modified would you feel you had to run the car into the ground due to your extra investment (though not much) and maybe, more worryingly, re-sale problems.
Re what I was told at the Vokswagen garage, apparently it had been discussed in Dublin (which I took to mean "at the top levels") only days previously and this was the edict. I wonder is that VW's official PR line though - I'm sure they're "supportive" and "developing new technologies" and being "socially and environmentally responsible". In fairness, maybe the heading for this thread should say "Post '02 VW's not for Pure Plant Oil conversion" - I fairly sure thats what we both had in mind when we had our 40 second conversation.