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New Mobil1 formulas
grant - 1 month ago
I did a little sleuthing. I will also reach out to my moles in the labs (exxonmobil and BPL).

The new Mobil1 ESP meet's Porsche's going forward C40 standard but explicitly not backward compatible with A40. I need to read the data more carefully to guess why. the simple answer is, of course, "because Porsche says so".


The replacement for the old Mobil1 0W40 is called FS. It meets Porsche A40. Note it has a higher HTHS (possibly the spec we care most about since it measures film strength when hot and under pressure). It meets ACEA A3, which was always the heart of A40 anyway.


I find it curious that they do not specify the HTHS spec, while they do for the other oil that does NOT meet A3 (3.53 which is below the magic 3.8).

The new FS 5W40 also meets A40. By starting with a 5W rather than 0W, it will have better film strength, at the expense of poorer flow at stupid-low temperatures (like -20F). Your owners manual gives the temperature ranges for 5W40 vs 0W40. Of course, track use over-rides that ( and they now say so, in the new "driving on a racing circuit" manual supplement, included with the GT cars,yea!)

So, for most of us i would suggest FS 5W40 if available. Both Edge 0W40 and 5W40 also meet A40 and ACEA A3.

Happy confusing oil changes,



Boxsterra - 1 month ago

Thanks for the info, Grant.
I leave it to the dealer to put in the right stuff, no matter 0 or 5, but after my 0W-40 top-up quart is done, I'll be looking for the 5Ws.
My 13S, now at >88k is beginning to need (more) top ups between changes. Maybe the 5W will mitigate that.
needs more explanation When the motor wore out (didn't fail per se, but zippo compression), i built, with a local shop, a 3.4L race motor with hardened liners (nickis) JE pistons, Carillo rods, etc. Its not that fast, since its an early S with the super slow feedback loop on the FI, but it torque y and supposedly durable. That said it burns a TON of oil, especially at the track. Rings and bores show essentially now wear (!?) and usage has never changed from almost new. By a ton i mean > 1 qt/1000mi on the street and and ~ 1.5qt in 4 hours of (very hard) track driving (2 days at DE). This is using M1 15w50 with a normal oil temp per my gauge of about 250-260 deg F.

So usage can be all over the map.

An increase in use however, is not a good sign. Something wore and may continue.



I do notice when I wind out the engine more often, it requires a few ounces at a time.
Castrol Edge 5w-40 looks interesting. Somewhat similar numbers to the M1 5w-40, and it has an A3/B4 rating, for what it's worth.

Edited 1 time(s). Last edit at 11/23/2021 07:58PM by Laz. (view changes)
that's way within spec and very normal. However - changes in consumption are typically not good.

yes, the edge 5w40 is supposedly very good - per specs, per the guy who formulated it, and i have used it.

Then again, both he and Audi's "tech support of last resort" both think most oils are fine - just make sure you have the right amount, right weight, and change it enough that its neither broken down, diluted with crap or out of additives (especially those that neutralize acids)


Although it might've been Marc W who once said fuel pumps can be damaged if running dry.
The new formulations have more to do with the new exhaust particulate filters than anything else.

Happy Boxstering,

Pedro Bonilla
1998 Boxster 986 - 299,000+ miles: [www.PedrosGarage.com]

PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

Racecar spelled backwards is Racecar

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