SAE Paper on Engine Wear with 20 wt. oil

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In 1964, Chevrolet recommended either SAE 20 or 20W or 10W-30 for temperatures above 32°F---with no specific upper temperature limit. "For sustained high speed driving when the temperature is above 90°F, SAE 30 or SAE 10W-30 may be used."
Yes but as noted the SAE grading system has changed several times since then. It was pre-HT/HS but likely around the 2.9 range.
 
I would have more faith in Turbo or GDi engines using the 20wts if they were with better oils than group 3 otc oils. If it were using a Amsoil or something with a bit more ooomph, I wouldn't worry so much.
 
Tens of millions of cars and trucks running 16 and 20 grade oils for billions of miles nor 2 to 3 decades of use to include many back spec'ed cars running thinner oils,
XW-16 hasn't been in use for 30 years. And its been discussed many times that engines where xW-16 is specified have special design features for that visvosity. That's why bottles of xW-16 have their own unique identifying API symbol on them. When is the Farrari getting some 16 ... why not just go for some 8?
 
Please let us know why the ultra thin crowd ignores this metric and why you feel this metric is not important.
Because the roads aren't littered with 1000s of "blown-up" engines, and cars will either get T-boned and totalled, or rust to nothing but 4 wheels before the engine fails. That's the standard response. But as said many times by many people, there is a correlation between HTHS viscosiy and engine wear in some engine components. HTHS headroom is added wear protection, so it really doesn't hurt to have it.
 
Just took this from my 2023 Amg Cla45. Amg is confident enough in 0w20 to use it as the only oil for the cla45. (Dont forget mercedes also uses 10k service intervals). Obviously the engine was designed to run this, but it is worth noting there are no other options like the 35s have. I personally dont have enough balls to run a flavor outside of what is specced here, but I will do 5k intervals with mobil 1 or liqui moly. Maybe even a 10k with ravenol ecs
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I don't think long term reliability is a concern for racecars, whatever lasts the race and performs the best is what counts. I don't think the builders would care if the engine exploded 5 seconds after being the first to pass the finish line.
Over half of the allotted engines for the season have to last and be used for two full race weekends (practice, qualifying, race). Bottom line is 20W oils are what is used in these harsh conditions. Slightly heavier oils are used for break-in, using special break in oils.
 
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Over half of the allotted engines for the season have to last and be used for two full race weekends (practice, qualifying, race). Bottom line is 20W oils are what is used in these harsh conditions. Slightly heavier oils are used for break-in, using special break in oils.
Not to nit pick, but 20W = 20 Winter, IE, the first part of 20W-50. If you mean a 20 grade it should be expressed as SAE 20 or 20 grade or similar. It's common that new folks are confused about the Winter grade/rating system, so veteran members using it incorrectly isn't going to help them understand it properly.

My understanding is that the viscosity used varies depending on the track, but I don't follow NASCAR super closely. Maybe @High Performance Lubricants has some more info.
 
If you are concerned about engine wear at engine startup, 0W-8, 0W-16, 0W-20, 0W-30, and 0W-40 all have the same thin viscosity at engine startup.
Just noticing this statement now. No they don't. They all just have to be below the viscosity limits for that Winter grade via CCS @ -35C and MRV @ -40C.

For example, let's look at the PDS for the HPL Premium Plus series and focus on the 0W-xx oils:
Screen Shot 2023-01-13 at 10.10.35 AM.jpg


Now, let's pay particular attention to the 40C visc:
0W-8: 28.33cSt
0W-12: 31.03cSt
0W-16: 40.01cSt
0W-20: 47.22cSt
0W-30: 53.44cSt
0W-40: 79.68cSt

And this continues as the temperature drops, the heavier oils are always going to be heavier, but all of them will fall within the CCS/MRV limits to maintain the 0W-xx Winter grade/rating.
 
And that's what the OEM's are counting on. As I said, it's something that won't matter to Joe Average, but the CAFE numbers matter to the OEM, so it's a win-win for them. Just because something is measurable doesn't mean it's significant, ergo, just because going thinner may accelerate wear in some areas doesn't mean that this will be of consequence to the useful life of the equipment, particularly if the tendency is for it to be taken out of service by other events/conditions.

The problem is when somebody drags out the "pile of failed engines" fallacy rather than acknowledging the nuance of the above.

Are you not familiar with the OP's inclination to run super thin oils in Super Cars that call for grades like 10W-60? If not, then I understand why you might be inclined to think that preposterous.
Excellent point but I'd also like to add the that "pile of failed engines" fallacy cuts both ways. Many proponents of thicker oils in their responses leave readers believing that their engines will seize or suffer a lubricant related repair bill as soon as the warranty period expires.
 
Excellent point but I'd also like to add the that "pile of failed engines" fallacy cuts both ways. Many proponents of thicker oils in their responses leave readers believing that their engines will seize or suffer a lubricant related repair bill as soon as the warranty period expires.
Many state that? Where?
 
Over half of the allotted engines for the season have to last and be used for two full race weekends (practice, qualifying, race). Bottom line is 20W oils are what is used in these harsh conditions. Slightly heavier oils are used for break-in, using special break in oils.
Race cars have big oil coolers to control the max oil temperature, and therefore the oil operating viscosity. Also, journal bearings create more MOFT as RPM increases, so the high engine RPM along with controlling the oil temperature to keep bearings from smoking themselves works in a race car for the planned life of the engine.
 
How about starting with numerous fuel dilution threads.
Many here bring up the point that excessive fuel dilution on top of an already thin oil isn't doing any favors for the resulting viscosity. Doesn't take a lot of fuel dilution to noticeably reduce the KV100. The thinner the oil gets, the more wear can occur.
 
Race cars have big oil coolers to control the max oil temperature, and therefore the oil operating viscosity. Also, journal bearings create more MOFT as RPM increases, so the high engine RPM along with controlling the oil temperature to keep bearings from smoking themselves works in a race car for the planned life of the engine.
Exactly. Furthermore, they don't care about lasting 100K miles.
 
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