......and a lower HTHS does what for protection?

Look, I run a 0w-40 in most of my cars because I want the fastest possible cold pressure build and yeah everything you said is correct. However an otherwise identical engine that is normally specced for a higher HTHS oil EVERYWHERE on earth but the US is only specced lower to marginally reduce pumping losses and gain some mpg.

The really confusing part comes into play that when you are using an ultra high grade oil vs a "normal" one you can actually not only maintain MPG but gain a little even you move up on weight. I have personally experienced this in 4 cars, I moved my LS460 and my dad's L405 5.0 from their spec XX-20 of generic variety (whatever was on sale) to M1 ESP 0w-30 and they each gained 1.2-1.7 mpg on a long trip and on a 5000 mile average.

The trips were done same time of the year as the comparison point as I log my results when I go somewhere so I knew what the cars did last time. They gained because that oil had a huge amount of effort put into it to have less pumping losses than any other oil on top of insanely good HTHS for a given weight. That said the 0w-20 version will outperform the XX-30/40 variants.

My 0w-40 cars all get slightly better mpg than if I used a VW504.00 rated XX-30 that isn't an oil from the same family. It's small, but 2-5% mpg across a fleet is make or break for companies on the US so if they go the other way from what I did to gain some mpg in exchange for less engine lifespan and durability on track etc they will.

Its why performance cars here say in the manuals to not use the street oils on track in many cases, the exceptions are Porsche, GM and some others who already spec the heavy/high HTHS stuff in the big dog cars as they don't care about mpg in those products.

 

Every damn time. The engineers rarely ever get what they truly want

 

I always say that if we get our way, we'll never release anything because we just want to keep on churning and making it better!

 

Yep lol!

It's also so so so obvious when a product was made by engineers who were given low/near zero restraints. It also tends to cost a massive amount up front but nearly never gives issues/has a very low total cost of ownership and maintenance.

 

"Better is the enemy of 'good enough'" is a phrase often mentioned....though I hate it!

Side note: I really do need to make the aviation thread in Clubhouse that I have long desired. That's where me and Mike will find our most common ground!

 

What is the apple and what is the orange. Please explain what you think it’s so unique with the climate , the roads and how people drive in the US that it has no overlap with anywhere else. Draw me a Venn diagram.

You’re basically saying if I drive from Canada to the US, I must immediately drain my slump and fill with 0w-16 or else I have inadequate lubrication.

Please also explain in scientific terms what engineers actually determined unique to the US? Not in fruit terms.

You do know that engines are engineered for global markets right?

you do know that EPA compliance regulations mandate that the written maintenance instructions given to the retail buyer must be consistent with the maintenance performed (ie oil viscosity) on the test vehicles during federal certification or else there is federal penalties right? You do know that this is federal law and not written by automotive engineers right?

 

I added a set of driveline fluids to my personal stock for the TVD cars and truck. I have enough diff/PS/TVD fluid for all of them to be serviced once each and they were also all done when I bought them/recently so I likely won't use this stock for 4 years.

Also brought my stock of ZF5/6/8 up to 12/12/48 quarts on standby, WS was already at 24+, ATF+4 was already at 24, and I have a little dex merc on hand

Only thing left to get to be able to turn my brain off for my own cars is some syncromesh trans fluid for the Jetta and a spare set of Redline MTL for the S4. Jetta gets changed often enough it's an actual concern

 

Yes. I also have an outside fascination with aviation.

 

Speaking of planes, any warthunder players here?

 

thinner oils are used for fuel economy in the US.

 

Clearances are the gaps between moving parts; tolerances are the allowed variation from those gaps. Mass‑produced engines typically use similar clearances regardless of the oil specified. "0W" is not a fixed weight but an SAE J300 viscosity range. The SAE defines the test temperatures and limits for cold‑cranking viscosity (CCS) and low‑temperature pumpability (MRV). To meet J300 an oil must

(1) be pumpable to the pickup at the specified low temperature and
(2) have CCS/MRV values within the SAE limits.

“0W” does not simply mean “flows faster," it means it either does or does not at the pickup tube.

The second number is high‑temperature viscosity measured at 212°F (100°C): lower numbers (e.g., 16, 20) are thinner at operating temperature; higher numbers (e.g., 40, 50) are thicker.

Very low‑viscosity oils (0W‑20, 0W‑12, 0W‑8) form thinner lubricant films. Engineers compensate by increasing bearing width to spread load, which raises friction and can slightly increase wear; manufacturers also request blenders to rely on different additives to help compensate (check out some of the stout 0w20 oils like redline that close the gap between it and select 5w30 oils) but at the end of the day you can only do so much and they have to accept this trade‑off for increased fuel‑economy and emissions gains.

There are a couple studies available by the SAE conducted by mfgs like Nissan, and some done by I believe Chevy with a Vegas taxi company. I'll get to those later. Some studies have been commissioned by oil companies.
https://www.researchgate.net/publica...erioration#pf3

The idea that 0W‑20 will inevitably ruin an engine is unfounded; likewise, 20W‑50 is not universally best. Its more of a design flaw/machining debris and using the wrong oil at the wrong temperature for the wrong duty cycle. The above studies show that 0w20 in select trials, had very minimal to nil effect on wear and the package was infact satisfactory. If we want to drill into validity of the data we can but this is already a long post.

When choosing oil, weigh your priorities versus the OEM’s: cost, local temperatures, used‑oil analysis trends, duty cycle/driving style, and required industry or manufacturer approvals (e.g.MB229.5 specs). Let those objective factors drive any decision to deviate from the factory recommendation. Plus if you drive a Toyota, they graciously have a ambient temperature chart with a wide variety of oil weight recommendations in the global manual. Avoid using the product labels that use buzzwords and confusing claims (e.g., “Advanced Fuel Economy,” “Extended Protection,” “Hybrid Motor Oil,” “Truck & SUV,” ESP x2/x3) to sell product without clearly explaining technical differences. Retail shelves are full of such claims focus instead on proven specs and approvals. Look it up on the spec sheets.

If all else fails, KISS and just follow the oil cap every 5k/6 months .......

Side Note:
For the “Thin Motor Oil Avengers”: with this whole motor oil shortage and Toyota and others releasing TSBs to the effect of being a Thickie, will or have OEMs released a magical OTA update to increase those tolerances and clearances. ECU driven electric oil pumps, and VVTI systems specs?

Will they provide another magical OTA update to bring those tolerances, clearances, ECU driven electric oil pumps, and VVTI specs again when this subsides?

 

Yeah all of the above is a "duh" info dump to anyone who knows how this works. I've said before a very high grade 20 can close the gap to a mainstream 30 for HTHS but brand to brand/type to type the higher rated oil will have a better HTHS.

As far as cold flow again no ****. A 0w-XX will outflow a 5w-XX when cold and has a lower temp where it will flow at all. Hence why it's always better to use a 0w oil if you can, the only drawbacks are lifespan of the oil but that's nullified with shorter changes so it's a total non-issue other than cost.

When the recommend oil for a given engine is the same, higher weight all across the world expect ONE place I tend to believe the reason for the lighter spec isn't for increased protection.

You added a nice summary but what exactly were you trying to prove/point out?

 

The BMW calls for 0W-20 synthetic so that's what it gets.

The F150 calls for 5W-20 synthetic blend. I run synthetic 5W-20.

 

What the BMW really wants is 20w-50.

But probably best not to spoil her like that though because she will expect it all the time.

 

Since you're tuned and running Ethanol, you really should switch that up to a 5W-40.