Comma Motorsport 5w50 vs Motul Sport Ester 5w50

n0v0s

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By comparing the requirements for that spec and the data sheet or a voa for the oil.
I have been disregarding the recommendation by manufacturer. Just look at the approved list. I thought this to mean it's been run through the OEM test procedure for various parameters to be measured and passed.

I thought the recommendation meant it meets stuff like min Hths, tbn etc values but not necessarily run through tests to measure how the Hths changes over use etc.
 
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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..?
There is no way to tell. Here, again, is the value in an approval. You may know or can find out what the approval requires.
 
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I have been disregarding the recommendation by manufacturer. Just look at the approved list. I thought this to mean it's been run through the OEM test procedure for various parameters to be measured and passed.

I thought the recommendation meant it meets stuff like min Hths, tbn etc values but not necessarily run through tests to measure how the Hths changes over use etc.
You can’t make an assumption based on a data sheet that an oil meets or exceeds a certification.

You can, however, make an assumption based on a certification that an oil with that approval will have characteristics and performance that is statistically similar to other oils with that same certification.
 

n0v0s

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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.
Nothing quantitative, no oil analysis has been done, but will begin to from now on.

Main bearing failure, oil pumps looking like I showed and chain snap seems to be becoming more common. How much of that is neglect accumulation from following BMW's ridiculous oci recommendations versus mechanical shear issue, I don't know.

The amount of peak cyclinder pressure being produce is enough to lift head with m12 headbolts when in compound turbo configuration with some builds. Thus again, I repeat, this posed question of finding more robust oil that superceedes LL04 for peace of mind incase it is an issue, considering how far away from original LL04 engine brief things are

Edited to add, this was BEFORE having this discussion on this thread. I now appreciate LL04 is actually very stringent.


But also there have been some interesting other discussion points raised and allowed me to appreciate there are other oils that in theory are more robust and what I was after.

I also feel I understand a bit more, about why they are better.


.
 
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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).
Shell Rimula is a capable alternative to Delvac. In Egypt, driving conditions are not easy on engines; extreme day temperatures north of 38 celcius, sometimes crossing 40 for several days in a hot wave, dusty roads, "stop 'n go" traffic, "5000 ppm" Sulphur in diesel, you can fill-in the rest. Yet, Delvac and Rimula are praised by truckers for holding up in even worse cases as with dump trucks easily hitting 1m kilometers on the odometer for many. I'm in the agro-business, and truckers experience are a lot better on-ground benchmark than UOAs, and marketing claims. So we can take that as a donut of trust not printed on the jug.

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?
Rubia 8900 10W-30 has stringent approvals such as Mack EO-O PP, MB 228.51 and VDS-4. Actually, I have little idea about its performance, we have it on the shelves, however, it's very rare to find people even talking about it.
For almost the same price, Delvac 1300 Super 10W-30 is very stout and is well praised. Both should be fine.

Usually, there is less VIIs in 10W-30 than 15W-40 because of less spread between cold rating and operating temperature grade. In case of temporary or permanent shear, 10W-30 will be more shear-stable (loss of less HT/HS viscosity) than 15W-40, but 15W-40 will retain slightly higher viscosity because it was formulated from a higher viscosity base oil even though it sheared more. Think of it this way: 10W-30 HT/HS started fresh at 3.5, for instance, and ended up to 2.8, and 15W-40 started at 4.1 and ended up to 3.1, so even though it has less shear stability, it still has higher HT/FS than 10W-30.
So a higher winter rating is a good indicator of HT/FS (base oil HT/HS without VIIs contribution to viscosity).
Both will offer solid film at the end as long it's higher than HT/HS of 2.6 after temporary or permanent shear takes place with higher base oil viscosity of 15W-40 and the thicker 20W-50 offering the necessary cushion for higher temperature applications. Let the ambient and oil temperatures on the dashboard decide which one will go in the sump. Not the OEM committed to CAFE. Going below 2.6 for HT/FS (HT/HS after shear) and things will go exponential for the worse.
Don't worry much about cold start, even 20W-50 will be good in your climate.
 

n0v0s

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Shell Rimula is a capable alternative to Delvac. In Egypt, driving conditions are not easy on engines; extreme day temperatures north of 38 celcius, sometimes crossing 40 for several days in a hot wave, dusty roads, "stop 'n go" traffic, "5000 ppm" Sulphur in diesel, you can fill-in the rest. Yet, Delvac and Rimula are praised by truckers for holding up in even worse cases as with dump trucks easily hitting 1m kilometers on the odometer for many. I'm in the agro-business, and truckers experience are a lot better on-ground benchmark than UOAs, and marketing claims. So we can take that as a donut of trust not printed on the jug.


Rubia 8900 10W-30 has stringent approvals such as Mack EO-O PP, MB 228.51 and VDS-4. Actually, I have little idea about its performance, we have it on the shelves, however, it's very rare to find people even talking about it.
For almost the same price, Delvac 1300 Super 10W-30 is very stout and is well praised. Both should be fine.

Usually, there is less VIIs in 10W-30 than 15W-40 because of less spread between cold rating and operating temperature grade. In case of temporary or permanent shear, 10W-30 will be more shear-stable (loss of less HT/HS viscosity) than 15W-40, but 15W-40 will retain slightly higher viscosity because it was formulated from a higher viscosity base oil even though it sheared more. Think of it this way: 10W-30 HT/HS started fresh at 3.5, for instance, and ended up to 2.8, and 15W-40 started at 4.1 and ended up to 3.1, so even though it has less shear stability, it still has higher HT/FS than 10W-30.
So a higher winter rating is a good indicator of HT/FS (base oil HT/HS without VIIs contribution to viscosity).
Both will offer solid film at the end as long it's higher than HT/HS of 2.6 after temporary or permanent shear takes place with higher base oil viscosity of 15W-40 and the thicker 20W-50 offering the necessary cushion for higher temperature applications. Let the ambient and oil temperatures on the dashboard decide which one will go in the sump. Not the OEM committed to CAFE. Going below 2.6 for HT/FS (HT/HS after shear) and things will go exponential for the worse.
Don't worry much about cold start, even 20W-50 will be good in your climate.
You're a star, thanks for helping me to understand better. I feel a lot better informed now :D

Regarding the Rubia, I have about 20L of it currently and can get more 10w30 for almost give away price compared to buying other 15w-40 HDEO at £40-45 typical price for 7.5L. Thus if I use the Rubia, I can afford to keep oci to very short intervals (Mann oil filters are also inexpensive). So I could change the 10w30 3x over by 6000miles and still cost way less than single change of 15w-40. (Effort to change doesn't bother me, I'm always tinkering).

Reason for mentioning this, is the bit where you explain about 10w30 being more shear stable - despite the lower starting Hths to begin with of fresh 10w-30. If both 15w-40 and 10w-30 are ran for the same interval (e.g. 6000miles), then from what you explained, the 10w30 will of course end up with lower Hths.

But if the 10w30 is changed at say, shorter 2000-3000 mile intervals, the end hths could still remain closer to 3.5 as the oil resisted shearing better, and in theory be better idea than leaving 15w-40 in for a full 6000mile interval where it will shear quicker and for longer and end with even lower Hths than the 10w-30 after 3000miles. Is this reasonable to assume?

The cost saving just further strengthens idea. But from what I can tell, the 10w-30 meets stringent standards, is still considered a "stout" HDEO. And more shear stable than 15w-40 as long as oci not too long to allow it to shear down much less than 3.5 hths.

And finally, it seems even though the 10w-30 has lower fresh Hths, to provide less "cushion" to bearings than 15w-40... That the 10w-30 will resist (temporary) shearing down better during hard use because it has less VI improvers. Is this negligible? I.e. higher fresh Hths is more significant benefit over having less VI improvers added with regards to shear and loss of oil film

Sorry for the many questions, I find this stuff really interesting. Lots to learn
 
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Reason for mentioning this, is the bit where you explain about 10w30 being more shear stable. Despite the lower starting Hths to begin with of fresh 10w-30, if both 15w-40 and 10w-30 are ran for the same interval (e.g. 6000miles). From what you explained, the 10w30 will of course end up with lower Hths.

But if the 10w30 is changed at say shorter 2000-3000 mile intervals, hths could remain closer to 3.5, and in theory be better than leaving 15w-40 in for 6000mile interval. Is this reasonable to assume?
That's true in case of permanent shear, which is not the case as in wet-clutch motorcycle engines where VIIs are meshed into tiny pieces like a spaghetti. of course, permenant shear still has a place in car engines but it is very insignificant in comparison and is not a subject of concern.
Temporary shear happens all the time, where the VIIs fully align with the flow and have no contribution to the viscosity at regions such as piston rings and valves train particularly timing chain, and regain its shape once again and contribute to the viscosity out of these regions.
A higher base oil viscosity will ensure sufficient protection for these full shear regions.

Let's assume Rubia has HT/HS at 3.6. It will be 2.8 at the valve train, no matter how fresh the oil is and start 3.6 at the bearing (because HT/HS is in effect and VIIs do experience high shear not full shear) and end up to roughly 3.2 by the end of drain interval and still 2.8 at valve train region.
 

n0v0s

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That's true in case of permanent shear, which is not the case as in wet-clutch motorcycle engines where VIIs are meshed into tiny pieces like a spaghetti. of course, permenant shear still has a place in car engines but it is very insignificant in comparison and is not a subject of concern.
Temporary shear happens all the time, where the VIIs fully align with the flow and have no contribution to the viscosity at regions such as piston rings and valves train particularly timing chain, and regain its shape once again and contribute to the viscosity out of these regions.
A higher base oil viscosity will ensure sufficient protection for these full shear regions.

Let's assume Rubia has HT/HS at 3.6. It will be 2.8 at the valve train, no matter how fresh the oil is and start 3.6 at the bearing (because HT/HS is in effect and VIIs do experience high shear not full shear) and end up to roughly 3.2 by the end of drain interval and still 2.8 at valve train region.
Ahh ok! I see the distinction now between permanent and temporary shear and how the VII play their role in this in various parts of engine.

My original main concern was that of the 10w-30 causing premature wear to bearings due to oil film maybe not being adequately maintained but there is atleast less effect here if maintaining short oci.

I recently inspected cams, not terrible but not great. Definitely had some debris in oil at some point, (stupid long oci). I've got stiffer valve springs tham stock anyway to prevent valve float so that wont help. Chains and sprockets are all renewed so that is some peace of mind. These were also recently removed and length/slack evaluated against old chains and pics, holding up great after 5000miles regular abuse at 5500rpm using 5w-30 HDEO (Rubia TIR 9900) with 3k mile oci. So maybe that is enough to go on to be content with 10w-30. And evaluate with oil analysis.

Power will soon be quite a bit higher, 550bhp+ and likely 1100nm+ and Mobil Delvac MX 15w-40 for around £50 10L and 5k mile intervals, seems widely available here. So I most likely will switch over to 15w-40. Will sleep more peacefully :D

Bit of a wildcard question/new can of worms (sorry!) - I came across a Mannol 5w60 that claims ester base and absolutely no approval specs as expected for this type of oil. It's stupidly cheap and cannot find any info anywhere.. which screams run(!). If something like this was decent pao + ester base, what considerations would this bring to table if mixing my into my 10w-30? In context of it being full synthetic base with big difference between 5 and 50winter grade and so a lot of VII added, but having high Hths... Would it then mean the Hths is worsened in valve train because of extra VII, or that the Hths is now higher regardless?
 

n0v0s

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£55 for 10L 😅😂
Screenshot_20221023-025652_Adobe Acrobat.jpg
 
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Would it then mean the Hths is worsened in valve train because of extra VII, or that the Hths is now higher regardless?
10W-60 has a lot of VIIs and thus, the high HT/HS, I also have little knowledge about how certain esters behave like a VII and how they might affect the final viscometrics of the oil.
But generally, 10W-60 HT/FS might be anywhere from 2.6 to 3.2, just a guess because Gokhan's calculator needs:
Relative density at 15.6 celcius
Viscosity at 40 celcius
Viscosity at 100 celsius
And HT/HS which is missing from TDS
These inputs are needed to estimate HT/FS at temporary full shear.
Still a good oil and chances are good it maintains an effective film due to the presence of esters in the formulation.

We need input from a more knowledgeable member.
 
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