Mobil One FS x2 5w50

[SpecM]

Whats the skinny on this "new" version of 5w50? I've been using Mobil 15w50 for years in my old BMW and would like something a touch thinner.

The Mobile website says it still carries Porsche A40 approval, ACEA A3/B3 A3/B4, MB 229.1/229.3, blah blah.

Its probably GTL like the new M1 0w40 FS, but is it the same formula? Same add packs? Is it just a thicker 0w40 FS? It seems to have the ZDDP content as 0w40, and just a touch less than the 15w50. And whats up with the "x2"?

 

[SpecM]

Mobil Infos

 

[SpecM]

Anyone have any info or experience on this oil?

 

[wings&wheels]

I regularly use it in my Rover 90 2.5NA diesel w/ a newly rebuilt engine (after talks with the Mobil tech folks) and my Wife's 996. I have run it in my TR6 and Rover Series III when I didn't have enough 15w-50 on hand for the change.

Observations based on my use (none really unexpected):
1) is a bit noisier on startup then w/ Redline 10w-40 996
2) pumps up a bit quicker on cool days then the 15W-50 TR6 & Series
3) hot idle pressure is pretty much the same as the 15w-50 TR6 & Series

Since 5w & 15W-50 are specced for all of these cars, I generally use 5w in those that see cooler weather, but will interchange as necessary.

 

[H_Tech]

If your looking for a good 5W-50 I've been using the Ravenol Racing Rally Synto 5W-50. Its one of their ester and PAO race oils. My urS4 loves it when compared to Shell or Mobil and it conveniently available on Amazon. Way less oil consumption on 80 plus degree days at 26psi of boost. Also I believe its used in the EKS Audi s1 rally cross car.....so it can be that bad.