2017 Corvette / Mobil 1 ESP 0w40 / 7.1k miles

[dparm]

This is the third full interval with the Mobil 1 ESP Formula 0w40. I pushed it past my usual 20% OLM reading and let it go down to around 3% which was around 2k extra miles. But this also worked out to a lot of track time: about 15 hours! Several of those track days had ambient temps in the mid-90s but overall oil temps and pressures stayed steady. Never got oil temps above 265 F.

Blackstone said that overall it looked good, but again noted the viscosity was a bit low. I've since switched to Motul 300V 0w40 which I hope holds its viscosity a little better.

I'm still really impressed with how this thing continues to hum along without any major issues despite the hard driving. I just had it dynoed last month and it laid down 400whp, meaning it's still producing the claimed 460 crank hp (if you assume 15% drivetrain loss).



Code


OIL Mobil 1 ESP 0w40 Mobil 1 ESP 0w40 Mobil 1 ESP 0w40 Mobil 1 5w30 Mobil 1 5w30 Mobil 1 5w30

MILES IN USE 7,095 5,230 5,915 3,848 5,651 741

MILES 28,480 21,385 16,155 10,240 6,392 741

SAMPLE TAKEN 3/24/20 9/13/19 2/26/19 6/22/18 9/22/17 4/12/17



ALUMINUM 5 5 6 6 10 3

CHROMIUM 1 1 1 1 2 1

IRON 21 18 35 34 53 48

COPPER 2 3 3 5 13 28

LEAD 0 2 1 1 1 1

TIN 0 0 0 0 0 0

MOLYBDENUM 70 66 69 80 76 84

NICKEL 0 0 0 0 0 0

MANGANESE 0 0 0 1 2 2

SILVER 0 0 0 0 0 0

TITANIUM 0 0 0 0 0 0

POTASSIUM 1 2 1 2 5 10

BORON 178 175 156 66 54 106

SILICON 7 7 10 12 40 74

SODIUM 4 4 7 4 5 7

CALCIUM 1515 1441 1539 1103 956 1043

MAGNESIUM 16 30 119 779 682 624

PHOSPHORUS 744 719 769 735 627 692

ZINC 830 798 801 819 733 753

BARIUM 0 0 0 0 0 0



INSOLUBLES 0.2 0.1 0.1 0.1 0.1 -

WATER 0 0 0 0 0 0

FLASHPOINT �F 395 410 390 395 390 SHORT

SUS VIS 210�F 61.5 64.4 62.5 56.8 54.8 -

cSt @ 212�F 10.65 11.44 10.92 9.29 8.71 SHORT

TBN 2.6 3.6 2.8 4.4 4.6 6.2

TAN 4.6 4.6 3.7 2.8 4.7 1.9

 

[tcp71]

Isn't it supposed to be bad if the TAN number exceeds the TBN number?

 

[dparm]

Originally Posted by tcp71
Isn't it supposed to be bad if the TAN number exceeds the TBN number?


The answer is: it depends. Some oils will have a high starting TAN, so without knowing the virgin (brand new out of the bottle) TBN and TAN, you can't definitively say that oil must be changed when TAN > TBN. That being said, I don't think the oil I used has a naturally high TAN.

Some deeper discussion on the subject:
https://bobistheoilguy.com/forums/ubbthreads.php/topics/1970704/TBN/TAN_CrossOver_in_UOA--_Wha

 

[buster]

Looks really good, especially with 15 hours of track time. Wear control is excellent.

Regarding viscosity, Mobil has to be aware that their 0w40 drops into 30 grade territory. It always has. The HT/HS of this oil is around 3.6. In order to prevent this, one could go with Redline 0w40 which has a HT/HS of 4.2, but it's not good for LSPI issues.

Mobil did 2 years worth of testing with this oil for this car. I would absolutely stay with it.

 

[A_Harman]

Fuel dilution? I see your UOA lab doesn't provide a fuel dilution measurement. I doubt that the oil is shearing in a GM LS-type engine.
In hot trackday conditions, I wouldn't be surprised if the ECM calibration is injecting a lot of extra fuel to save the cats.

 

[dparm]

Originally Posted by A_Harman
Fuel dilution? I see your UOA lab doesn't provide a fuel dilution measurement. I doubt that the oil is shearing in a GM LS-type engine.
In hot trackday conditions, I wouldn't be surprised if the ECM calibration is injecting a lot of extra fuel to save the cats.


Forgot to include it, but yes, Blackstone provides fuel numbers. It's been <0.5% every time.

 

[spinkick]

Thanks for this! Was considering amsoil signature series or the new factory fill. I also have a 17 Grand sport. My LT1 has a supercharger added, so I am particularly interested in protecting the motor as it doesn't come stock with boost

 

[buster]

dparm, just thinking out loud here....Driven 0w40 DI would be a great choice for this engine. This oil is mPAO/POE and has a SA of .72 and has top notch, very shear stable VII's. If I ever deviated from the Mobil 1 ESP 0w40, this would be my choice.


https://www.drivenracingoil.com/di40-0w-40-synthetic-direct-injection-performance-motor-oil-1.html

 

[Gasbuggy]

Very impressive UOA. Also glad to see the new 0w40 performing well in the GM engines.

 

[spinkick]

Never have seen driven oil before. Is it new?
Originally Posted by buster
dparm, just thinking out loud here....Driven 0w40 DI would be a great choice for this engine. This oil is mPAO/POE and has a SA of .72 and has top notch, very shear stable VII's. If I ever deviated from the Mobil 1 ESP 0w40, this would be my choice.


https://www.drivenracingoil.com/di40-0w-40-synthetic-direct-injection-performance-motor-oil-1.html


I've never seen this brand. Is it new?

 

[Patman]

The wear numbers are good but something always bothers me about an oil that loses that much viscosity, I figure that in the long run that means the engine might not be as clean inside, as the thinning is the breaking down of the VII. I'm very glad I'm sticking with the 5w30 version of ESP Formula, it stuck at it's starting viscosity of 12.1 for my entire 7200 mile interval on my last UOA.