If one was to use new oil to make bio diesel which one would be the best ie;canola,sunflower etc?

regards andy

1. The cheapest.

2. The one with the highest gel point.

IMHO anyway.

Depending on your location, the Melting point of the oil may limit your use of the biodiesel, unless heating of the fuel is available.
In other locations this may not be an issue.

If in high termperature locations, where the minimum temperature rarely drops below 20°C, palm oil, coconut oil or beef fat may be used as the conversion to biodiesel drops the melting point of these below 20°C. these oils have a higher specific energy than the liquid oils and the biodiesel from them also has a higher specific energy (more power per litre)
Where the climate precludes the use of these high melting point oils, the use of oils which have a low melting point is required to get a biodiesel which had a lower melting point also.
While it is possible to make biodiesel from linseed oil or fish oils, these are not recommended as biodiesel feedstock as the polymerisation propensity of the oils is transferred to the biodiesel. This may make the biodiesel unsuitable in some cases.

Thus, biodiesel use is generally limited to climates where the fuel does not drop below -10°C. By blending the biodiesel with petrol, kerosine or diesel, the lower usable temperature can be extended a little.

Regards,
Tony