there are reasons silkolene is better than Castrol RS, oilman has explained countless times on here why, and even provided test results.

to quote from another post ;

POPEYE wrote:
so what you are saying is that castrol is shit basically bigcry.gif


No, it doesn't say that. The point is that there are better quality oils out there that are tougher and better for extreme applications. By this I mean modded cars and track days etc.

The Castrol is labelled a synthetic but in fact it is not a proper one (pao/ester based), unlike the others mentioned here which is evidenced by the shear stability which meets the minimums required by API and ACEA.

In conclusion there are better oils out there.