Thoughts on oil type/weight for 5BW?

[Kawman]

Blackstone labs doesn't give TBN results - I guess I don't car about that, as I change the oil every 2 or 3 days.

6/3/26 test - Mobil 1 5w30
7/11/26 test - Royal Purple 5w30
8/15/26 test - Mobil 1 5w40
Next test - Motul 5w40 300V

Look how the change from 5w30 to 5w40 is bringing done my numbers. Hopefully another drop in the next analysis with Motul 300V 5w40 racing oil, followed by another drop when I start using Motul 5w50.

"It's a delicate balance between pushing machinery to its absolute limits and showing it enough kindness to hold it together" - Ken Miles

 

[blkout]

Blackstone labs doesn't give TBN results - I guess I don't car about that, as I change the oil every 2 or 3 days.

6/3/26 test - Mobil 1 5w30
7/11/26 test - Royal Purple 5w30
8/15/26 test - Mobil 1 5w40
Next test - Motul 5w40 300V

Look how the change from 5w30 to 5w40 is bringing done my numbers. Hopefully another drop in the next analysis with Motul 300V 5w40 racing oil, followed by another drop when I start using Motul 5w50.

"It's a delicate balance between pushing machinery to its absolute limits and showing it enough kindness to hold it together" - Ken Miles



View attachment 35510

Blackstone does give TBN results, you just have to pay extra for it. I have numerous samples with TBN. There should be an option box on that form that you fill out when you send in your sample. You may not have noticed it or cared about it since you change your oil so frequently. Here's one of my last samples from the Camaro ZL1 before I sold it.

 

[RDATLTE]

There has been mention of Dexos but, no mention of the possibility of the denial of a warranty claim when using a non specified / non Dexos oil.

 

[KatyTxCT5V]

If you're using any of the top oils, then changing every 2-3k is likely overkill. Have you ever done an oil analysis and looked at your TBN? If not, you might be surprised that you can probably go 5K miles without any issues. Exceptions would be if you're running high ethanol fuel in which case I would recommend oil changes no later than every 3K miles.

As everyone has their unique situation, I change my M1 0w40 SC oil annually regardless of the mileage due to the very low annual miles driven on this car. I worry about the fuel dilution due to low annual miles due to short drives. It does sit in a 75F garage protected and never has seen any inclement weather. All fluids get changed at the proper intervals on all my cars.
Currently my 22 5BW has 1857 miles. I reserve driving the 5BW for stress relief, especially when my wife is not available.

I have some others cars to drive depending on the occasion, but primarily work from home. I have a 2013 Explorer with about 31k miles, lol. Sold the 16 Z06 and it had a few thousand miles.

 

[Carguyshu]

couple of things. the 5w-50 dexosR is on the heavy end of 50 and the 0w-40 is on the low end of 40. The chemistry of each is also pretty differentt. ZL1 said 0w-40 is fine for all conditions, including track, once supercar (formerly ESP) oil was created. That oil was basically made specifically for corvette/camaro and this engine family as a joint effort project between GM and Mobile1. Previously they wanted on 1LE cars a switch for 5w-30 (the oil the engine was originally designed around and for) to 15w-50 as the tire/suspension grip led to issues with sustained high Gs since the LT4 in camaro (as well as blackwing) uses a wet sump vs the dry sump in corvette. At spring mountain they said in testing there were still times where blackwing would have oiling issues if there was extreme constant G force for lengthy time periods with no straights for oil to run back down. i have tracked my car very often in a lot of conditions (lots of times with over 100+ ambient temp) and several different tracks and have never seen any oil pressure or oil temp issues using 0w-40 supercar. I had considered 5w-50, but given that there are no issues to solve protection wise I'm struggling to justify that. I now have a precision pack car with stickier tires so we'll see if that extra grip is an issue or not. I'm doubtful it will be. Using a heavier weight oil can increase film strength and can also lessen worry about sheering down, but it can also increase engine oil temp. The engineers seemed to have done an excellent job on blackwing with everything coolant wise (especially manual cars) and the limiting factor I've also found has been tires getting too hot, not anything driveline.

The car calls for dexosR 0w-40, so if you run something besides that you could potentially run into a warranty issue. Originally only Mobile 1 supercar was certified, but that is no longer the case as there are several other options.