0w20 for heavy driving?

My whole premise is that car makers will spec a thin oil for fuel economy and then they'll have an addendum saying to use a thicker oil for extended high speed driving and racing.
 
Originally Posted by aquariuscsm
My whole premise is that car makers will spec a thin oil for fuel economy and then they'll have an addendum saying to use a thicker oil for extended high speed driving and racing.




What constitutes high speed? Most would say freeways and todays modern engines turn at 2000rpm or less at those speeds.

Racing is specific.
 
Originally Posted by aquariuscsm
My whole premise is that car makers will spec a thin oil for fuel economy and then they'll have an addendum saying to use a thicker oil for extended high speed driving and racing.



Car makers do not spec thin oils in Europe and Australia
grin2.gif
 
Originally Posted by PowerSurge
Originally Posted by ZeeOSix
Just asking for some proof of the claim. As long as you don't do something crazy like use 20W-50 in -25F start-ups, and there's adequate oil flow - ie, the PD oil pump can effectively pump the oil, meaning the correct/appropriate viscosity is used for the ambient temperature - then start-up wear will not be a strong function (if any) of the viscosity.

So if you (or anyone else) can dig up an official study that shows more start-up wear occurs between xW-20, xW-30, xW-40 and xW-50 as a sole function of those different viscosities when appropriately used for their rated ambient temperature, then I'm all ears.


For starters, give this a read: https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3539152/1


Pretty much goes along with what I said above. Can you detect the truth from the fiction in that thread?
 
Originally Posted by LotI
fwiw, Mazda says 5w-30 outside the US and Canada.

It means you should run a 30 grade if you want to reduce wear.

It means you should run a 20 grade if you want 0.5mpg better.


No, Mazda says 0w20 in America and Canada and 5w30 OR 0w20 elsewhere.

In all the ROW charts I've seen, 0w20 is listed as a suitable oil grade for Skyactiv engines.

When it comes to OP's question, unless you're actually racing, just run what the manual recommends and you'll be fine.
 
Last edited:
Originally Posted by jeff78
Originally Posted by Gokhan
0W-20 is the recommended oil for most new BMWs and Audis driven on the autobahns at 140 mph now.
But the manual would recommend a thicker oil if these cars were driven on the track, no?

Genuine question for anyone who's actually driven one of these cars on the autobahn at those speeds - how hard is the engine working to cruise at 140mph? Obviously it depends on the particular model, but some of these cars are putting out 600+ hp.

My 100hp unfaired motorcycle will do 140mph, but it would be a proper Eyetalian tuneup. I reckon a high end German luxury car would have a far easier time of it.

Racing models, such as BMW M, Audi R8, etc. spec thicker oil, not 0W-20.

At 140 mph most street-legal cars would be in the high end of their rpm range, increasing the oil temperature.

You can see the 2020 Audi oil recommendations in the Audi maintenance schedule below. Now, it's down to two oils -- VW 508.00, which is a 0W-20 based on ACEA C5, and VW 504.00, which is a mid-SAPS oil based on ACEA C3, typically a thick 5W-30 with an HTHS = 3.5 cP.

https://www.audiusa.com/content/dam...Maintenance-Schedule-Model-Year-2020.pdf
 
So why is 0W-20 specified for US and Canada only - and 5W-30 for everywhere else in the world?
 
Originally Posted by dubber09
page 6-27

https://cdn.mazda.ca/common/en/pdf/...32050342.1583610575-294194473.1583610575

Except U.S.A., Canada
SKYACTIV-G 2.0, SKYACTIV-G 2.5
Use SAE 5W-30 engine oil.

page 6-28

SKYACTIV-G 2.0, SKYACTIV-G 2.5
Use SAE 5W-30 engine oil. If SAE 5W-30
engine oil is not available, use SAE 5W-20
engine oil.
The quality designation SM or SN, or
ILSAC must be on the label.
SKYACTIV-G 2.5T
Use SAE 5W-30 engine oil. If SAE 5W-30
engine oil is not available, use SAE 0W-30
or SAE 10W-30 engine oil.
The quality designation SM or SN, or
ILSAC must be on the label.


What countries would we be talking about in an English language manual other than the USA or Canada?
 
Originally Posted by ZeeOSix
Originally Posted by PowerSurge
If I see data proving that it does in fact cause higher wear I'll even stop running 0w-20 in my Tundra.


There have been lots of thread discussions in this forum with links to engine wear studies showing that higher viscosity can lower wear. You can find all kinds of technical studies with a Google search.

And obviously, if an engine isn't pushed hard then a lower viscosity will still do it's job. It's when the oil temperature gets higher than "normal" is when thinner oil loses film thickness, and more wear can occur. Seems to be a bigger wear increase when gettig down into the xW-16 viscosity range. xW-20 will work for most, but going xW-30 adds some insurance to maintain an adequate oil film thickness between parts for increased temperature, fuel dillution and shearing.


Which ones where? And when? Were they using Group III, II+, iV, and V oils?
 
Originally Posted by Jackson_Slugger
What countries would we be talking about in an English language manual other than the USA or Canada?

Mexico 🇲🇽 according to the manual.

Probably the reason is the high cost of synthetic oil there. Therefore, they recommend conventional oil (5W-30).
 
Originally Posted by ZeeOSix
Originally Posted by PowerSurge
Originally Posted by ZeeOSix
Just asking for some proof of the claim. As long as you don't do something crazy like use 20W-50 in -25F start-ups, and there's adequate oil flow - ie, the PD oil pump can effectively pump the oil, meaning the correct/appropriate viscosity is used for the ambient temperature - then start-up wear will not be a strong function (if any) of the viscosity.

So if you (or anyone else) can dig up an official study that shows more start-up wear occurs between xW-20, xW-30, xW-40 and xW-50 as a sole function of those different viscosities when appropriately used for their rated ambient temperature, then I'm all ears.


For starters, give this a read: https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3539152/1


Pretty much goes along with what I said above. Can you detect the truth from the fiction in that thread?


You totally ignored Gokhan's posts. That's called cherry picking.
 
Originally Posted by Gokhan
Originally Posted by Jackson_Slugger
What countries would we be talking about in an English language manual other than the USA or Canada?

Mexico 🇲🇽 according to the manual.

Probably the reason is the high cost of synthetic oil there. Therefore, they recommend conventional oil (5W-30).


This is what I've been told in the past by a contact of mine. Economical reasons and availability in many other countries. It's just not PC for corporations to come out and say.
 
Originally Posted by PowerSurge
Originally Posted by ZeeOSix
Originally Posted by PowerSurge
Originally Posted by ZeeOSix
Just asking for some proof of the claim. As long as you don't do something crazy like use 20W-50 in -25F start-ups, and there's adequate oil flow - ie, the PD oil pump can effectively pump the oil, meaning the correct/appropriate viscosity is used for the ambient temperature - then start-up wear will not be a strong function (if any) of the viscosity.

So if you (or anyone else) can dig up an official study that shows more start-up wear occurs between xW-20, xW-30, xW-40 and xW-50 as a sole function of those different viscosities when appropriately used for their rated ambient temperature, then I'm all ears.


For starters, give this a read: https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3539152/1


Pretty much goes along with what I said above. Can you detect the truth from the fiction in that thread?


You totally ignored Gokhan's posts. That's called cherry picking.


I read his posts, and I'm sure he agrees that there is no real difference in start-up wear due solely to the viscosity factor between 5W-20, 5W-30, 5W-40 and 5W-50 if they are all used in ambient temperatures that they are specified for. There won't be a lack of lubrication (which is what causes wear) due to the fact that they will still flow well and be supplied to moving parts by the positive displacement oil pump. That's my point ... the "5W" is the important spec for cold start-up, not the 20, 30, 40 or 50.
 
I'm not going to attempt to speak for him. I value his opinion so hopefully he will chime in soon. As far as "no real difference", even if the difference is small it matters to me, one way or the other.

Edit: I see you keep going back and editing your posts so I'll add that there's more to it than just saying because of the positive displacement pump there is no difference in startup wear. I'll wait for him to expound on the points he made in the other thread that you're ignoring. He will know what I'm referring to.
 
Originally Posted by PowerSurge
I'm not going to attempt to speak for him. I value his opinion so hopefully he will chime in soon. As far as "no real difference", even if the difference is small it matters to me, one way or the other.


I'm sure it makes a big difference in Atlanta ...
wink.gif
. Well, I guess my choice to use 5W-30 over 5W-20 falls into the same reason category. I really don't care what other people use, but there's really no scientific test data that I've seen that says using 5W-30 instead of 0W-20 or 5W-20 in ambient temperatures they are designed for is going to give any difference in start-up wear.
 
Originally Posted by PowerSurge
I'll add that there's more to it than just saying because of the positive displacement pump there is no difference in startup wear. I'll wait for him to expound on the points he made in the other thread that you're ignoring. He will know what I'm referring to.


Such as? If the same volume of oil is being delivered to engine parts by the PD oil pump, then where's the lack of lubrication?
 
Originally Posted by ZeeOSix
Originally Posted by PowerSurge
I'll add that there's more to it than just saying because of the positive displacement pump there is no difference in startup wear. I'll wait for him to expound on the points he made in the other thread that you're ignoring. He will know what I'm referring to.


Such as? If the same volume of oil is being delivered to engine parts by the PD oil pump, then where's the lack of lubrication?


Such as the engine speed. Lower engine speed during startup due to higher viscosity oils can cause slightly more wear during startup. It's covered in one of the links he posted. It also covers why engines wear more during idle, if I remember correctly.
 
Originally Posted by PowerSurge
Originally Posted by ZeeOSix
Originally Posted by PowerSurge
I'll add that there's more to it than just saying because of the positive displacement pump there is no difference in startup wear. I'll wait for him to expound on the points he made in the other thread that you're ignoring. He will know what I'm referring to.


Such as? If the same volume of oil is being delivered to engine parts by the PD oil pump, then where's the lack of lubrication?


Such as the engine speed. Lower engine speed during startup due to higher viscosity oils can cause slightly more wear during startup. It's covered in one of the links he posted. It also covers why engines wear more during idle, if I remember correctly.


A computer controlled engine doesn't idle at cold start-up any differently with xW-20 through xW-50.
 
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