Oh. My. God. Custom mixed oil blends? Seriously?

 

The attached are from "the 996 essential companion".
Have at it.

 

Yep, seriously. At least with Mobil 1. The LN Engineering article I linked in my original post goes into the gory details, but the short version is that the Mobil 1 formulation available today meets only API SM spec, which has lower amounts of certain key inorganic anti-wear additives than the API SH spec Mobil 1 that was "off the shelf" when the 996s were developed and sold new by Porsche. The change in API spec was done to prolong catalytic converter life (should any oil leak past the piston rings, the inorganic wear additives accumulate on the cats, slowly deactivating them), but at the expense of high-temperature film stability and wear prevention.

The blend I use takes advantage of the fact that the Mobil 1 4-stroke motorcycle racing oil has very high levels of the inorganic wear additives essential for high-temperature, high shear part protection--even higher than the SH-spec car oil. The resulting blend is very close to a 5W-40 SH spec Mobil 1 which is the original oil specified by Porsche.

Plus...I'm a chemical engineer by training, working in the oil industry. Making custom oil blends is *fun*

 

So next time I change my oil, I should switch from my usual Mobil1 0w-40 to Mobil1 5w-40 since it has "very high levels of the inorganic wear additives essential for high-temperature, high shear part protection" ?

 

The Mobil1 5W-40 on the shelf today is also API-SM graded, which means it also has the lower levels of the anti-wear additives that all SM-graded oils do, versus the SH oils the 996 engines were designed for and tested on.

The key in the blend I'm using is the use of the Mobil1 4T 10W-40 4-stroke motorcycle racing oil...it's not SM graded and has much higher levels of the anti-wear additives. Blending the 4T with SM graded Mobil1 0W-40 gives a near 5W-40 SH graded Mobil1 (which you can no longer buy).

 

What ratio of the 2 oils are you recommending to use? Equal parts? My C4S Cab. uses 10 quarts.

 

Mobil 1 0W-40

 

50/50 is fine and is what LN engineering's article on oil suggests. I blend 5 qts 0W40 regular Mobil1 and 4 qts 10W40 of the Mobil1 4T racing since my 996 takes 9 quarts on an oil change.

My first post in this thread gives more details and link to LN's article,

 

Cool. I'll try your blend on my next oil change. Forget the Royal Purple, I'd rather stick with Mobil1, therefore you sold me on your blend of Mobil1.

 

Castrol Syntec 5W40 is SL rated. Should be better than the Turbo Diesel 5W40 Mobil 1. Right? Seems like probably the best and easiest i.e. no mixing, and you can buy it anywhere. Thoughts? Agree? Disagree strongly?

 

probably in the om

 

Oil formulas and standards change all the time. That's why all of the 0W40 guys who blindly follow the recommendations from 10 years ago may want to consider switching to a 2010 spec.

 

Mobil1 15-50 for mine...its the thickest...i like it...

I send my oil out for testing every oil change...so far excellent wear numbers

 

+1 on not blindly following anything...but, in this case, I'm not. Oil formulations have to balance a lot of performance factors. The SH to SM spec change traded decreased high-temperature wear resistance for increased cat converter life in cars with significant oil consumption. Our *friends* at the EPA in DC care about emissions, not engine reliability. Cats are cheap; engine rebuilds are not. Knowing this and the nature of current oils is what drove my decision to go the route I have.

As for the Syntec SL 5W40...that's another possibility. Read the LN article, check the numbers (particularly HTHS test results IMHO). Like I said before, I like messing about with oil blending but I fully understand that many others don't (like She Who Must Be Obeyed , when I make a mess of the garage).

 

I went for Valvoline Racing VR1 5W50 (only for Europe)

In Bob's the oil guy there's a pile of info

C. Navarro has a fantastic exposition in his web too.