Having just purchased an 02 BA XR6T I have been looking around at engine oils available to match the Ford spec of SJ/CF SAE grade of 15w-40.
I have come to the conclusion after finding an article called Oils Against Oils that Ford R1-340 is the oil to use, owing to damage still being able to happen at start up caused by the oil being to thin when cold. EG, 0w-40 or 5w-40 grade.
The testing of oils was carried out on a dyno supplied by COME Racing Engines here in Melbourne.
So have a look at the site there are some surprise's as to which is the best Synthetic Oil.
Final results are,
2. BP Visco 5000
3&4 Both Mobil 1 grades tested.
5. Hi-Tech HTO
6. Shell Hellix Ultra
7. Royal Purple
8. Castrol R
9. Castrol SLX
By the way its good to have an XR6T that someone else has taken the depreciation on.
xrhp6 now with a T on the end.