Why Going to xw20 Oils?

Nick1994

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One thing I've wondered about is why all these car companies are going to 20 weight oils. I have no doubt a 0w20 can lubricate an engine greatly, but what's the reasoning behind it? For example, the Chevy Silverado has always been specced for a 5w30, and now they're calling for a 0w20. Is it tighter engine tolerances or CAFE standards for fuel economy? Same with Toyota Camry's, once were calling for 5w30, now they call for 20 weights. Another question I've wondered: if you got 2 cars that called for 0w20 and ran them in the same exact environments, miles, and all factors were the same for say, 300,000 miles. One of them was run on a 20 weight and another on a 30 weight, would there be any differences in engine wear? I've never had a car yet that called for a 20 weight, and with 5w40 in my TDI, I have no experience with 0w20 and have always been curious. Thanks.
 

CT8

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Originally Posted By: aquariuscsm
It's all about fuel economy.
YES it is !!!
 
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Tighter clearances allow for lighter oils. Lighter oils also provide slightly better fuel economy. They make since for people like me that have a 1 mile drive to work. Any oil...even 0w20 is thicker than necessary on start up, no need for an even thicker oil in these situations.
 
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Originally Posted By: CT8
Originally Posted By: aquariuscsm
It's all about fuel economy.
YES it is !!!
the reason numerous mfgs have back speced cars is....
 
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Originally Posted By: gregk24
Tighter clearances allow for lighter oils. Lighter oils also provide slightly better fuel economy. They make since for people like me that have a 1 mile drive to work. Any oil...even 0w20 is thicker than necessary on start up, no need for an even thicker oil in these situations.
This, pretty much. Oil should always be as thick as necessary, but as thin as possible. Modern oils can have lighter ratings while retaining good viscosity and performance in the hottest, highest-shear parts of the engine. What's not to like?
 
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Let's not forget the for years and years the 5w30 was shearing to a 'thick' 5w20. So, in reality most vehicles were running a 5w20 anyway.
 

OVERKILL

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Originally Posted By: 04SE
Let's not forget the for years and years the 5w30 was shearing to a 'thick' 5w20. So, in reality most vehicles were running a 5w20 anyway.
Considering shear is wildly application dependant I don't think we can toss out that gross generalization as readily as we like to around here. My Expedition doesn't appear to shear anything. The M5 on the other hand does. Both are OHC V8's with relatively good sized sumps. I wouldn't be surprised if an engine like a good old pushrod Ford/Mopar/Chevy in lopo trim didn't do a whole heck of a lot of shearing with the "old" 5w-30's, whilst the higher power density OHC 4-bangers and 6's probably did.
 
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I started out both of my 07 Fords with M1 5-30. After about 50K I switched to M1 0-20 because of the great performance "fsskier" got from that oil in engines calling for 5-30 oils. with nearly 100K on 0-20 there's no way I would change to a heavier oil. This is from Fsskier on 0-20 with 300K on the engines. http://www.bobistheoilguy.com/forums/ubb.../3.#Post3552369
 
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Originally Posted By: Ram01
But will using 0w20 get you 200k out of a motor now??
Are you joking or is that a serious question? I don't see any issues for engines to make it on 20 weights to 200k+ and that has been well proven.
 

Nick1994

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Originally Posted By: tig1
I started out both of my 07 Fords with M1 5-30. After about 50K I switched to M1 0-20 because of the great performance "fsskier" got from that oil in engines calling for 5-30 oils. with nearly 100K on 0-20 there's no way I would change to a heavier oil. This is from Fsskier on 0-20 with 300K on the engines. http://www.bobistheoilguy.com/forums/ubb.../3.#Post3552369
Do you have any UOA's for both oils?
 
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Originally Posted By: Nick1994
Originally Posted By: tig1
I started out both of my 07 Fords with M1 5-30. After about 50K I switched to M1 0-20 because of the great performance "fsskier" got from that oil in engines calling for 5-30 oils. with nearly 100K on 0-20 there's no way I would change to a heavier oil. This is from Fsskier on 0-20 with 300K on the engines. http://www.bobistheoilguy.com/forums/ubb.../3.#Post3552369
Do you have any UOA's for both oils?
No, I don't do UOAs. The only thing UOAs are for is the condition of the oil, fuel, coolant, dirt, etc.
 
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