- Dec 14, 2002
- New Jersey
My 2011 135i is specified to take Castrol XO (now called long life 75w-90, different than the 75w90 LS sold at auto zone), since it has an open differential. I suppose it could also take the XJ fluid, despite being an open diff, but whats the point at only 300 hp/tq? So, if one looks at the specs of XO and XJ, at least XO to me is pretty good: 40C Vis. XO: 100cSt XJ: 177.2 cSt 100C Vis. XO: 15.2 cSt XJ: 25 cSt Brookfield at -40C XO: 42900 cP XJ: 140000 cP Viscosity Index XO:160 XJ:174 Pour Point XO: -57C XJ: -54C http://www.benquip.bz/uploads/products/files/SAF_XO_SAF_XJ_B1174_96.pdf The NZ site has a newer PDS for XO which has slightly different values. The only one really substantial is Brookfield viscosity at 50400 cP. http://msdspds.castrol.com/bpglis/FusionPDS.nsf/Files/BF4E6C4EE23364B180257C63000D68FA/$File/Syntrax%20Long%20Life%2075W-90.pdf But if you compare anything else, the values are ???? M1 is slightly lighter in the 90wt range at 14.6 cSt at 100C, but also has a much lower VI and PP at 146 and -39C respectively. https://mobiloil.com/en/gear-lubricants/mobil-1-synthetic-gear-lube-ls Amsoil SVG, a personal favorite, is a good deal heavier at 16.8 cSt at 100C, VI of 167, PP of -48C, and a Brookfield of 70400 cP at -40C. http://www.amsoil.com/shop/by-product/gear-lube/severe-gear-75w-90/?page=%2Fstorefront%2Fsvg.aspx Redline 75w-90, which Im not personally a fan of, is also heavier, at 16.2 cSt at 100C, but has a worse VI of 155 and a Brookfield viscosity of 110000 cP, so pretty bad characteristics. http://www.redlineoil.com/product.aspx?product=57904 Fuchs Titan Sintopoid 75w-90 is recommended in many places as a replacement for XO. It has a VI of 179 and a 100C viscosity of 15.3, so pretty close to XO. The Dynamic Brookfield viscosity is worse, but no worse than the other domestic stuff, at 88500. http://www.opieoils.co.uk/p-983-fuchs-titan-sintopoid-sae-75w-90-synthetic-gear-oil.aspx The thing with Fuchs is that per their brochure, they rarely carry any actual approvals. Not that Amsoil, Redline or M1 do either necessarily... http://www.fuchslubricants.com/Content/downloads/20760_Gear%20Oils%20Brochure.pdf Ive always heard good stuff about Fuchs, but never used their fluids. They aren't cheap but aren't expensive - like $14/L which is less than Amsoil and Redline, but more than M1. Im just not that impressed with any of the domestic offerings now that I've seen the XO spec. Apparently XO can be had from the dealer and from Land Rover by the quart... XJ 140wt can be had from all over the place, since it is way more common, used in a lot of AMG and other applications... But Im not convinced that I want/need a 140wt diff lube. My car makes 300hp, and provides 300 lb-ft right off idle. What would you do???? Is Fuchs actually a good lubricant supplier? I don't know much about them...