Leon's Ignition Timing

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Tue 20 Jan 2004 22:45
Leon's Ignition Timing - Leon on Derv
I have been running my motor on 100% biodiesel for some time. Excellent stuff - recommend it. Someone told me that it would be an idea to wind the igintion timing back by about 2 degrees.

Two questions -

Is there merit in doing this - I know it would need to be advanced again if I were to revert to diesel.

Can it be done / easily done on a modern engine - ie the Mk IV Golf Tdi

Leon
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Wed 21 Jan 2004 23:14
Leon's Ignition Timing - andymc {P}
There is merit in that it helps to reduce NOx emissions, improving local air quality and reducing contribution to acid rain. Don't think it's essential though. Have to admit I haven't done it myself, but I understand it's a short & easy job. No doubt someone will be along to correct me! Try doing a search for "retarding injection timing" or something similar on the biodiesel forum -
biodiesel.infopop.cc
Fred's TDi forum may also help -
forums.tdiclub.com/cgi-bin/ultimatebb.cgi
Let me know how you get on. If you do it, I'd be interested to know whether you find any difference in performance/economy.
andymc
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Thu 22 Jan 2004 19:11
Leon's Ignition Timing - dieselhead
As I understand, the Cetane value of Biodiesel is 58 compared to 47 of diesel (shorter delay period between fuel injection and ignition for Biodiesel) so in theory you should get better power and more economy if you retard the injection timing slightly.
This is only relevant if Seat optimised fuel injection timing for power/economy for diesel operation and not the control of pollution.. worth moving it a few degrees and seeing if it makes any improvement.




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Thu 22 Jan 2004 19:32
Leon's Ignition Timing - DL
You'll need VAG-COM to do this adjustment..
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