Setting altruistic environmental-friendliness aside, does running your Fabia vRS on a biodiesel blend actually make any difference?

I decided to experiment with my

Very interesting, but a pity that wind, temperature and humidity varied during the exercise.

Now how about a back to back dyno test of Millers XFE-PD (how come that is in the engine at only 4500 miles?) against Fuchs Titan Supersyn SL PD 5W-40 - which I believe is the factory fill oil? The latter is a fully synthetic oil and should show measurable advantages over the Millers oil which is semi-synthetic.

The problems of trying to do a fair scientific test.

When I was at teacher training college I went to a talk about fair testing one weekend (yes, I was a student who was around at 9am on Saturday mornings!!!). The speaker said that if you had the hypothesis that taller children jump higher the only fair way to test it was to get a very tall child and measure how high they jumped.

Then get a saw and cut a centimetre off the legs and repeat the exercise. Then keep cutting and repeating. :eek:

I suspect that short of running the car for several hours in a large airtight but ventilated hanger (the fumes would play havoc with the results!) it would be nigh on impossible to get all the conditions to be a perfect match. Nice try though.

Perhaps the weather will be kinder during the next attempt.

Interesting experiment, though it was always going to be tough to prove a difference in such a small time.

I have been keeping one eye on biodiesel developments for some time because I have found better performance and consumption when running in France, they have had 5% over there for a few years now.

A few years ago I tried an experiment (on a private track) with my merc e320 cdi. Against advice, after it had done 10k, I filled with rapeseed oil i.e. straight vegetable oil, and used it exclusively for about 3-4 tankfuls using catering suppliers 20gal drums.

The results. It ran more quietly, slightly smellier and quite obviously down on power (felt like 20-30%) but essentially just fine. I then switched to a more sensible 60/40 diesel/svo mix (approx) with an additive to thin during the winter months. When I sold the car 40k later I had not experienced a single problem, the pump and injector problems I was told would occur didnt materialise. Whilst accruing an awful lot of track time I proved a point, just how resilient the compression ignition engine really is and how tolerant of fuel variance it is too. The pump and injector problems I was told would occur didnt materialise

I would not try this extreme with my pd engine but would have no qualms running with a blend of say 80/20 if I was forced to.