Which Oil for tracking?

[IamFODI]

BMW M didn't base their oil partnership decisions on any science lol. Well modern $cience maybe. BMW M oil was castrol for years, then a brief stint with Shell, now back to Castrol.

There have been various posts on BITOG and on the old M3Forum with info from Doug Hillary, a lubricant engineer with with direct and indirect knowledge of TWS and BMW's various engine developers, describing how Castrol collaborated with BMW's engineers and third parties. Castrol made special formulations for BMW (including a version of TWS for M engines), BMW's engine development involved input from Castrol. E.g.:

https://bobistheoilguy.com/forums/threads/bmw-and-the-10w60-thing.204781/page-3#post-3148080

https://web.archive.org/web/20200222162902/http://m3forum.net/m3forum/showthread.php?t=295656

Leaving all that aside, I find it highly unlikely that a company can develop and mass-produce reliable 8k+ RPM engines with >100 hp/L NA but then when it comes to lubricants just be like "eh, whatever, this oil is fine; just use it because the manufacturer is hooking us up." The more I learn about this stuff, the more the reality seems like the exact polar opposite of that. Guess I can't speak for everyone...

[bigjae46]

Every modern full synthetic oil can.

Is Mobil 1 a full synthetic? That does not meet BMW's LLF requirements.

[Tbonem3]

The only science involved was could the oil maintain the 15,000 mile oil change interval fiction.

Every modern full synthetic oil can.

[bigjae46]

BMW M didn't base their oil partnership decisions on any science lol. Well modern $cience maybe. BMW M oil was castrol for years, then a brief stint with Shell, now back to Castrol.

The only science involved was could the oil maintain the 15,000 mile oil change interval fiction.

[Tbonem3]

BMW M didn't base their oil partnership decisions on any science lol. Well modern $cience maybe. BMW M oil was castrol for years, then a brief stint with Shell, now back to Castrol.

[bigjae46]

For our engines, there's only one party that has done that testing, and that's BMW M. That means the only oil backed by that level of knowledge is BMW's own 10W-60. Everything else is a guess (varying levels of educated).

Agreed. I've seen too many S54s run a long time on OE oil. Its a known quantity. Although I think I could lower peak temps with another oil, I still run the OE10w-60.

[trackjunky]

HTHS, you mean?

I tend to agree, but AFAIK the reality is more complex. The more I learn about this stuff, the less I feel I know...



Generally, yeah. Very hard to tell what the base stocks are, though.

Can even be hard to tell shear, because viscosity loss could also be due to fuel dilution, which not all UOAs reliably catch (including the ones that have it as a line item).


If we want to talk about what really matters, it isn't any one spec, performance metric, or collection thereof; it's the performance of the formulation as a whole – how long engines live with it, on average. We can make a low-quality guess about this from looking at specs. We can make a slightly better guess from used oil analysis. But if we want to know, that takes real engine testing – the kind of thing no one outside of OEMs and a tiny fraction of engine builders (e.g. Cosworth) can afford to even contemplate.

For our engines, there's only one party that has done that testing, and that's BMW M. That means the only oil backed by that level of knowledge is BMW's own 10W-60. Everything else is a guess (varying levels of educated).

100% agree ^

I always run Castrol 10w60 with BMW OE filters. avg of 20 track days a year, for the past 12 years. Oil analysis on every oil change. Oil changed every other event.

[IamFODI]

And that's what matters.

HTHS, you mean?

I tend to agree, but AFAIK the reality is more complex. The more I learn about this stuff, the less I feel I know...

Oil with high quality stock will shear less no?

Generally, yeah. Very hard to tell what the base stocks are, though.

Can even be hard to tell shear, because viscosity loss could also be due to fuel dilution, which not all UOAs reliably catch (including the ones that have it as a line item).


If we want to talk about what really matters, it isn't any one spec, performance metric, or collection thereof; it's the performance of the formulation as a whole – how long engines live with it, on average. We can make a low-quality guess about this from looking at specs. We can make a slightly better guess from used oil analysis. But if we want to know, that takes real engine testing – the kind of thing no one outside of OEMs and a tiny fraction of engine builders (e.g. Cosworth) can afford to even contemplate.

For our engines, there's only one party that has done that testing, and that's BMW M. That means the only oil backed by that level of knowledge is BMW's own 10W-60. Everything else is a guess (varying levels of educated).

[Tbonem3]

And that's what matters. I don't care much about a VOA, more a UOA since oil is never new except for that first fill up. Oil with high quality stock will shear less no?

[IamFODI]

Make sure to look at the actual viscosity numbers because there are 5w50s that are heavier than some 10w60s just like there are 265/35/18 tires that are wider than other brands' 275.

Liquimoly 10w60 is quite heavy (something like 26 cst @100) where as castrol is more like a 40 weight.

For kinematic viscosity at 100º C, a.k.a. KV100 – the thing that determines the big number in the viscosity rating (40, 50, 60, etc.) – there's no overlap. Any xW-60's KV100 is always higher than any xW-50's, which is always higher than any xW-40's, etc.

Where you will see overlap is in other viscosity measurements, e.g. kinematic viscosity at 40º C or high temperature high shear (HTHS) viscosity. That's where you could have a "lower" viscosity grade that ends up with a higher viscosity measurement than a "higher" viscosity grade – e.g., a 5W-50 with a higher HTHS viscosity than a 10W-60.

[Tbonem3]

Well, I respect your point of view, and you are certainly free to run whatever oil you are comfortable with in your engine. I'll continue running 10w-60 in my tracked S54 until I get a clear and concise reason from BMW that a lower viscosity oil will provide the same OR BETTER protection than the 10w-60.

Make sure to look at the actual viscosity numbers because there are 5w50s that are heavier than some 10w60s just like there are 265/35/18 tires that are wider than other brands' 275.

Liquimoly 10w60 is quite heavy (something like 26 cst @100) where as castrol is more like a 40 weight.

[Slideways]

Easy answer - whatever 10-60 FCP offers

1. BMW (rebranded Castrol) 10-60
and when they stop offer that
2. Motul 10-60
and when they stop offering that
3. Liqui Moly 10-60

Other options
Porsche (probably rebranded Mobile 1) 10-60
Redline 10-60

[Feffman]

Good day all. I'm attaching the10W-60 oil spreadsheet I've put together over the past few years. All the information is from the manufacturers published information. I have it in an Excel spreadsheet as well. If you'd like a copy, e-mail Feffman@MVPTrackTime.com.

Feff

[Cronenberged]

Amsoil has a 10w60 now, but as other have stated stick with that and OE. Pennzoil would be the next best then liquid moly and Castrol if looking at shear and viscosity.

[S54330Ci]

Well, I respect your point of view, and you are certainly free to run whatever oil you are comfortable with in your engine. I'll continue running 10w-60 in my tracked S54 until I get a clear and concise reason from BMW that a lower viscosity oil will provide the same OR BETTER protection than the 10w-60.