Comma Motorsport 5w50 vs Motul Sport Ester 5w50

Car is turbo diesel, 5500rpm, getting on for 180bhp/L, and 1000-1100nm. Driven hard daily. OCI approx 5k miles (max 7K).
M1 FS 5W-50 is a solid choice if you want something stout in that flavor. But I'd definitely pick Delvac Extreme 15W-40 or MX 15W-40. An oil is more than the sum of its parts, so skip looking at base oil and giving it more weight in your decision.
You might want to look at these choices as well:
Amsoil ADP 15W-40
Mobil Delvac Modern Super Defense 15W-40
M1 15W-50 if it's available
Mannol Favorit 15W-50 is also a good performer.
I'm just concerned about ensuring there is sufficient oil film maintained on the bearings. I will do some more reading, but I was thinking to chose an oil with higher Hths and of better base stock to help achieve this under hard use.
HTHS and wear.jpeg

This figure applies for normal driving conditions. You stated that you drive hard, so pick up an HT/HS at 3.5 or higher for a cushion.
What else am I missing that makes the HDEO more suitable over the Petronas type oil?
HDEOs more often than not have less viscosity index improvers because they are formulated from higher base oil viscosity, meaning they offer better hydrodynamic and mixed lubrication and contribute to less deposits and sludge formation. HT/HS is irrelevant in full shear regions in engine and base oil viscosity has full effect. The term HT/FS is coined by @Gokhan and is discussed more thoroughly in his posts.
CAFE practise their favorite hobby to a lesser extent on diesel engines OEMs and this reflects on HDEO as well. Better protection. Less restrictions on viscosity, AW, and emissions.
And your engine is compression ignited, so pick something that serves this application. I'd use HDEO in gasoline engine, not the other way around any day.

Shear rate in engine.png
 
M1 FS 5W-50 is a solid choice if you want something stout in that flavor. But I'd definitely pick Delvac Extreme 15W-40 or MX 15W-40. An oil is more than the sum of its parts, so skip looking at base oil and giving it more weight in your decision.
You might want to look at these choices as well:
Amsoil ADP 15W-40
Mobil Delvac Modern Super Defense 15W-40
M1 15W-50 if it's available
Mannol Favorit 15W-50 is also a good performer.

View attachment 122223
This figure applies for normal driving conditions. You stated that you drive hard, so pick up an HT/HS at 3.5 or higher for a cushion.

HDEOs more often than not have less viscosity index improvers because they are formulated from higher base oil viscosity, meaning they offer better hydrodynamic and mixed lubrication and contribute to less deposits and sludge formation. HT/HS is irrelevant in full shear regions in engine and base oil viscosity has full effect. The term HT/FS is coined by @Gokhan and is discussed more thoroughly in his posts.
CAFE practise their favorite hobby to a lesser extent on diesel engines OEMs and this reflects on HDEO as well. Better protection. Less restrictions on viscosity, AW, and emissions.
And your engine is compression ignited, so pick something that serves this application. I'd use HDEO in gasoline engine, not the other way around any day.

View attachment 122232
I revised my original HTFS post yesterday.

 
Comma's oils are fine, they just don't have official approvals because for a small oil manufacturer like them it's just not worth for them to spend so much on getting official approvals.
 
But for your application ( referring to OP ) i think an excellent oil would be Shell Rimula R6M 10W-40, it's a very stout GTL based 10W-40 HDEO and the add pack is equally stout , with i think around 1200-1400ppm of Zddp, over 3000ppm of Calcium which means the TBN is close to 15.
 
Comma's oils are fine, they just don't have official approvals because for a small oil manufacturer like them it's just not worth for them to spend so much on getting official approvals.
“Fine” isn’t going to satisfy a manufacturer’s warranty lawyers when one needs an engine replacement.

The “it doesn’t make financial sense for official approval bc they’re a small manufacturer” excuse has had holes punched in it ad nauseam as well.

There’s really only two reasons for an oil manufacturer to not have certifications, especially ones that just require self-certification: either the oil is not intended to meet them because it far exceeds them (see HPL), or because it can’t meet them (see PQIA’s warning lists).
 
M1 FS 5W-50 is a solid choice if you want something stout in that flavor. But I'd definitely pick Delvac Extreme 15W-40 or MX 15W-40. An oil is more than the sum of its parts, so skip looking at base oil and giving it more weight in your decision.
You might want to look at these choices as well:
Amsoil ADP 15W-40
Mobil Delvac Modern Super Defense 15W-40
M1 15W-50 if it's available
Mannol Favorit 15W-50 is also a good performer.

View attachment 122223
This figure applies for normal driving conditions. You stated that you drive hard, so pick up an HT/HS at 3.5 or higher for a cushion.

HDEOs more often than not have less viscosity index improvers because they are formulated from higher base oil viscosity, meaning they offer better hydrodynamic and mixed lubrication and contribute to less deposits and sludge formation. HT/HS is irrelevant in full shear regions in engine and base oil viscosity has full effect. The term HT/FS is coined by @Gokhan and is discussed more thoroughly in his posts.
CAFE practise their favorite hobby to a lesser extent on diesel engines OEMs and this reflects on HDEO as well. Better protection. Less restrictions on viscosity, AW, and emissions.
And your engine is compression ignited, so pick something that serves this application. I'd use HDEO in gasoline engine, not the other way around any day.

View attachment 122232
Excellent information. Thank you very much for taking the time to post. I will read through Gokhans thread. I had a quick skim.

Regarding suggestions, I will see which of those are more readily available here in UK (delvac for e.g is a bit tricky to find from quick search).

If I'm understanding correctly, the HDEO that has thicker winter grade generally have less viscosity improvers added.

I.e.something like a 15w40 will use a use a thicker base stock to begin with and have viscosity index improver added compared to say a 5w40 (as the 5w is achieved with more VII added to base?)

And so from the charts, generally if there is thicker base stock used with less viscosity improvers used, then it will resist full shear the best which is what really matters to maintain oil film integrity under full load.

Finally, a hths of 3.5 seems to provide thick enough oil film to "cushion" and produce acceptable wear. But >4 would be ideal hths to aim for.

If I'm on right lines, how does the 10w30 Total Rubia 8900 I'm currently using compare? It's a "UHPD" blended HDEO. Likely will be hths of little bit higher than 3.5 (min for the many spec it meets that also allows 5w30 is 3.5) And probably has a bit more viscosity index improver compared to the 15w40 suggestions?

Thus doesn't seem optimal to me. I run short oci. But seems still best idea to change to 15w40 recommended above
 
Comma's oils are fine, they just don't have official approvals because for a small oil manufacturer like them it's just not worth for them to spend so much on getting official approvals.
How would you know that? The approval requirements are many and how would you know they meet them all?

People make this type of comment all the time, but the fact is you have no clue whether or not that is true.
 
“Fine” isn’t going to satisfy a manufacturer’s warranty lawyers when one needs an engine replacement.

The “it doesn’t make financial sense for official approval bc they’re a small manufacturer” excuse has had holes punched in it ad nauseam as well.

There’s really only two reasons for an oil manufacturer to not have certifications, especially ones that just require self-certification: either the oil is not intended to meet them because it far exceeds them (see HPL), or because it can’t meet them (see PQIA’s warning lists).
Comma does have pretty complete data sheets for their oils, they aren't hiding anything.
 
And so from the charts, generally if there is thicker base stock used with less viscosity improvers used, then it will resist full shear the best which is what really matters to maintain oil film integrity under full load.
Do you have a demonstrated problem with mechanical shear in this engine? Mechanical shear stability is dependent upon the specific engine and the quality of the VII being used. Not all are equal. Plus the amount of viscosity modifiers required to meet a grade designation and winter rating is also dependent on the base stock composition. All of which makes approvals more important since they provide demonstrated performance of an oil.
 
But for your application ( referring to OP ) i think an excellent oil would be Shell Rimula R6M 10W-40, it's a very stout GTL based 10W-40 HDEO and the add pack is equally stout , with i think around 1200-1400ppm of Zddp, over 3000ppm of Calcium which means the TBN is close to 15.
Thanks for your suggestions! Might be able to get hold of that here.

Please may I clarify, I always thought of the TBN to mainly give indication as to how good the oil will "buffer" acidic combustion products over its lifespan.

It seems there is more dimension to this. I.e. the additional constitutents that make up TBN value, like calcium also have a role in anti wear properties (to make up for lower zddp). So higher tbn = can assume higher amount of non zddp anti wear additives?
 
Thanks for your suggestions! Might be able to get hold of that here.

Please may I clarify, I always thought of the TBN to mainly give indication as to how good the oil will "buffer" acidic combustion products over its lifespan.

It seems there is more dimension to this. I.e. the additional constitutents that make up TBN value, like calcium also have a role in anti wear properties (to make up for lower zddp). So higher tbn = can assume higher amount of non zddp anti wear additives?
Not antiwear additives, but other additives yes.
 
How can you be sure that it meets or exceeds the requirements of the approval of the product doesn’t have the approval?
Yep. The proof is in the approval. Many oils might also say “recommended for” which in and of itself is completely useless in this regard.

People that can read the typical values on a PDS and determine the oil is an acceptable substitute for an approval are way beyond anything I can do.
 
The comma rep said (regarding the 5w50 Motorsport oil I attached data sheet for on page1);

"Please find attached our TDS for Motorsport 5W-50, the ZDDP for our Motorsport 5W-50 is about 0.10% 1000PPM regrettably we do not measure hths and noack for this product."

Don't measure, or don't want to share..?
 
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