This is a mucho discussed subject. Here's my 2 penneth.
Always use a full synthetic oil with a turbocharged car. The temperatures the turbo reach are much higher than a conventional non-forced induction engine. Normal mineral oils breakdown at much lower temperatures than syntheitc oils
leaving carbon deposits in vital oilways , such as the turbo oil feed, causing bearing starvation and turbo failure.
Next, is what weight/viscosity to use. I use 15W-50 Mobil1 for the protection it gives the engine at higher temperatures ( Castrol RS10W-60 is good one also ). Some use lower w numbers and or semi-synthetics,
because there is an argument that the hydraulic tappets suffer from use of the heavier oils.
As I understand it, the W number is related to the viscosity and how well the oil flows at low temperatures,
and the second number is how well the oil protects at high temperatures.
My reasoning is that it is better to have a top end rebuild than a bottom end one so I use the heavier oil.
Having said that, my e6 engine has covered 47k miles and although the tappets do rattle sometimes when cold,
I feel that my engine is in good shape, that is, it still pulls like an express train http://www.ltregister.f9.co.uk/graphics/biggrin1.gif border|EQU| 0 align|EQU| absmiddle >
Some on here have tried Magnatec since it was recommended by Coordsport/Ralliart and have found it to give Tappet
rattle, others have had success.
Magnatec is significantly cheaper than Mobil1 or Castrol RS, but it is based on a different synthetic technology
it may be even semi-synthetic.
My recommendation (there are no kickbacks from Mobil for me [img]http://www.ltregister.f9.co.uk/graphics/wink1.gif border|EQU| 0 align|EQU| absmiddle >) is Mobil1 Motorsport 15W-50
