GC 0W30

[smbrm]

Originally Posted by rice_classic

Good points about the anticipation of the oil degrading down to a lower viscosity. Just one thing though, I thought the SAE standard for an SAE 30 oil is a cSt range of 9.3-12.5 at 212 Degrees F, 100C.

Mobile 1 lists their 0w-20 at 8.7 cSt at 100C.
Mobile 1 lists their 0w-30 at 10.9 cSt at 100C.

The difference is only 2.2 cSt which is a pretty small difference and a dyno may only register a 1 hp loss.

I don't buy into the 0w-20... yet. I think most of it has to do with CAFE standards. However, I do know the NASCAR teams are racing on straight 0 weight oil and I know that thin doesn't mean less protection. On the race car I run a oil pressure and temp gauge and an oil cooler and I race on the thinnest oil I can for the temps I anticipate the oil will see for any given weekend.

If the 86 can make 10 psi of pressure for every 1000 rpms at 212F with 0w-20 oil then I will probably just stick with that. I theorize most new engines with a factory standard of running a thinner oil have probably increased their oil pressure to compensate. I have no tangible evidence of this, just hypothesizing.

Interesting, your comment about 0W-20 and CAFE. I would agree, however similar concerns were raised when the industry moved from 10W-30 to 5W-30 and then 5W-30 to 5W-20.

I am sure that the engine designers have figured out a way to make it work. Warranty costs and reputation maintenance are still an influence, competing with CAFE requirements.

Notice that the 0W-20 at 8.7 is near the top of the grade range(5.6-9.3), while the 10.9 is in the middle of the grade range(9.3-12.5). These differences can be significant, otherwise there would be no reason for grades at all.
As it relates to the concern over viscosity that is too low, there are other visocometric properties that need to be considered more so than Vk100.
I would suggest that you may wish to consider HTHS(High Temperature High Shear Viscosity: SAE xW-20 = 2.6 mPas min & SAE xW-30 = 2.9 mPas min) and HTHS stability as this relates more to oil performance in connecting rod big end bearings where highest hydrodynamic shear loads and higher temperatures than 100C are experienced.
Pressure also isn't everything. Higher oil pressures can negate the benefiit of lower viscosity as power is required to generate pressure. The real issue is hydrodynamic film thickness/load carrying capacity which is impacted by the design of load carrying capacity of the bearings relative to the viscosity characteristics and load carrying capacity of the oil under the temperature and shear conditions experienced in the bearings. Oil flow quantity can also be more important than pressure in ensuring maintenance of hydrodynamic wedge.

Also lower "designed" viscosity is better than lower viscosity due to viscosity shear loss as sheared viscosity loss generates broken moelcules that can contribute to other cleanliness related issues.

Viscosity loss due to excessive fuel dilution is also not good as the quantitative impact on viscosity is often not predictable(since the amount of fuel dilution can be unpredictable) and it can contribute to other oil degradation.

cheers

[rice_classic]

All good points. I don't think we disagree, just elaborating.

Like you're stating about pressure and flow characteristics. There is reason we talk about cSt as opposed to just pressure. Also the 100C takes into account the temp/pressure seen in other parts of the engine. The engineers aren't so daft that they would base the measured loads of various bearings solely on the reading from the oil temperature gauge measuring point, wherever that point may be. Remember that an oil at 10 cSt is NOT twice as thick as an oil at 5 cSt, some folks will make this mistake. A 2 cSt difference (like the difference between a 20 vs a 30weight at 100C/212F) is almost negligible but if it's the difference between 60 psi at 6krm and 50psi at 6k rpm, I'd rather have the 60psi. But if the 20 weight oil is 60psi at 6krpm and the 30weight puts me at 70 psi at 6krpm then I'd rather have the 20.

Pressure isn't everything but it is key. Running pushrod V8's at 9200 RPMS for 5 hours on SAE 5 weight oil @ 250-300 degrees F doesn't seem like it would protect much but Joe Gibbs would argue otherwise.

Here's a couple approaches that would solve any internet pontification merry-go-round.

1: What is the constant oil temp the engine is designed to run at with its recommended oil? One could then extrapolate the intended cSt and even HTHS point for safe or optimal operation.

2: There is a possibility that like most engines this engine was also designed around a 10 cSt measurement at 212F oil temp (which isn't achieved with a xW-20) but the engineers decided that 1-2 cSt lower rating (as provided by xW-20) would fall within safe operating parameters under normal driving conditions and not increase wear.

I remember when the Integra Type R was release and there were several interviews with the chief engineer about it's performance on the track and recommended a thicker oil for tracking purposes due to heat. Ferrari, Porsche, Lambo... all the same. Higher temps demand a thicker oil to maintain proper flow and pressure at high rpms.


People should visit this site. It's quick it's easy and has tons of good info:

http://www.bobistheoilguy.com/motor-oil-101/

Here's a good quote

As we increase the heat from 212°F to 302°F the most commonly recommended oil thins from 10 cS to 3 cS. The thicker oil drops from 20 cS to 4 cS. Note that in a very hot engine the difference between the two oils is now only 1 – 2 cS. In other words they have about the same thickness. There is little advantage to a thicker based oil as a 20W-50 at very high temperatures. No, the 4 cS oil is not twice as thick as the 2 or 3 cS oil. This difference is almost insignificant.

[mattles]

Since GC 0w30 is so thick I will only be running it as my summer oil -- since it gets to almost 120F here in the summer, and I tend to run the car pretty hard during the summer months. I'll likely switch to 0w25 or 0w20 once I find something I like that is easily available without ordering online.

[NeedsmoreCowbell]

How do y'all feel about motul 5w40 for track? Too much? Or just right?

[smbrm]

In the spirit of elaboration/clarification and not wanting to create an internet merry go round, I can only reiterate that part of the reason that low viscosity engine oils can work in applications that previously had not been considered possible is that the relationship between lubricant characteristics and operating conditions of an engine are better understood. Simple kinematic viscosity tests only measure under shear rates that gravity can generate. Understanding big end bearing operating condition requirements(as well as others) has been shown to be important to extracting fuel economy and power benefits while ensuring adequate film thickness for protection.

That is one of the reasons why the HTHS dynamic viscosity tests were developed to better reflect high shear areas such as connecting rod bearings. Kinematic viscosity did not provide adequate correlation to their operating conditions.

cheers

[rice_classic]

Originally Posted by smbrm

That is one of the reasons why the HTHS dynamic viscosity tests were developed to better reflect high shear areas such as connecting rod bearings. Kinematic viscosity did not provide adequate correlation to their operating conditions.

Help me wrap this up then for oil nerd in all of us. Please elaborate on the place oil pressure has in this whole equation.


Some easy definitions for the folks at home when comparing Synthetic oils for use in your new car:

CentiStoke (cSt): Measurement of viscosity (at Cold 40C and Hot 100C), "tendency to flow" at a given temperature. "pouring a cup of honey"
CentiPoises (cP): Measurment of Absolute (Dynamic) viscosity, "ability of something to flow through the oil", the internal resistance to flow. Excellent for measuring shear. "stirring a cup of honey"


How about some comparisons of popular Syn brands:

Examples:

Mobile 1 0w-20
Viscosity, @ 100ºC, cSt 8.7
HTHS Viscosity, mPa•s @ 150ºC 2.7

Moblie 1 5w-30
Viscosity @ 100ºC, cSt 11.0
HTHS Viscosity, mPa•s @ 150ºC 3.1

Amsoil Signature Series 0w-20

Kinematic Viscosity @ 100°C, cSt 8.3

HTHS Viscosity, cP 2.8

Amsoil Signature Series 0w-30
Kinematic Viscosity @ 100°C, cSt 10.5
HTHS Viscosity, cP 3.1

Castrol Edge with Syn 0w-20
Kinematic Viscosity @ 100°C, cSt 8.65
HTHS Viscosity, cP 2.6

Castrol Edge with Syn 5w-20
Kinematic Viscosity @ 100°C, cSt 8.88
HTHS Viscosity, cP 2.6

Castrol Edge with Syn 5w-30
Kinematic Viscosity @ 100°C, cSt 10.7
HTHS Viscosity, cP 2.9


These comparisons tell me that Amsoil 0w-20 has excellent Kinematic viscosity (flow) and excellent level of shear protection (no pun intended).


To Mr Cowbell. I will need smbrm to elaborate here because...
I would say the cSt of the 0w-20 under track temps will be too low and the pressure of the oil between the bearings will be too low thus putting the HTHS rating to the test unnecessarily. This is why I'm asking smbrm to now add his take on pressure.

[rice_classic]

Originally Posted by NeedsmoreCowbell

How do y'all feel about motul 5w40 for track? Too much? Or just right?

Just for reference

Motul 300V Power 5W-40 @100C 13.8 cSt HTHS 4.51

[Fly Guy]

Red Line 0w-20
Kinematic Viscosity @ 100°C, cSt 8.2
HTHS Viscosity, cP 2.7

[smbrm]

Hopefully helping to wrap up and not make this as complicated as it could get!


First let me say that my intent on weighing into this discussion was to comment on some of the oil properties(viscosity related) that in my experience in the industry were deemed to be critical when considering the use of low viscosity engine oils in high temperature applications. I believe the discussion has more relevance when HTHS viscosity is also considered. I would very much expect that HTHS viscosity performance, along with the other oil viscosity properties, is an important consideration in modern engine design. And it can be even way more complicated than even this!



The acceptability for use of any of the products mentioned is a discussion more appropriately debated between the user, the engine manufacturer and the respective lubricant suppliers.


However,those with higher HTHS viscosity should have higher viscosity(assuming all other operational aspects & fluid properties being the same) in connecting rod bearings and therefore should be able to carry more load(keep the journal and the bearing apart){the impact of any viscosity thinning not-with-standing}.


Those with lower HTHS should theoretically be able to deliver better fuel consumption(in comparison) and have the potential for more power as viscous drag will be lower, up to the point where conditions will not allow the oil film to be thick enough to keep the bearing and journal apart.


You also cannot forget that we are dealing with a passenger car, sorry sports car, albeit one that some people will take to the track and will on those occasions most likely be subjected to running under full throttle and higher rpm for longer sustained periods, loads and temperatures than when used on the road.


So consideration of the owners tolerance for risk/reward relating to how they feel about balancing durability vs. performance is also important.

The BRZ owners manual supports this with(see pages 410-413):


"...Oil viscosity (0W-20 is explained here as an example):
• The 0W in 0W-20 indicates the characteristic of the oil which allows
cold startability. Oils with a lower value before the W allow for easier
starting of the engine in cold weather.
• The 20 in 0W-20 indicates the viscosity characteristic of the oil when
the oil is at high temperature. An oil with a higher viscosity (one with a
higher value) may be better suited if the vehicle is operated at high
speeds, or under extreme load conditions...."


We know how thin of an oil is apparently acceptable based on the recommendation.
It makes sense that under more severe conditions a thicker oil may contribute to additional durability while compromising fuel consumption.


An important question for the engine manufacturer is whether there is an oil viscosity grade(within the range of available grades in the viscosity grading system) that is inappropriately too thick(over the engines expected operating temperature range) for an engine designed for a 0W-20 as its primary recommendation?

************************************************** ************************************************** ***************
For those who want to really get into it, some additional reading demonstrating how far from simple this topic really is:

http://www.substech.com/dokuwiki/dok...ournal_bearing :also look at the related internal links
http://www.vandervell.co.uk/images/s...gPerforman.pdf
http://www.ricardo.com/Documents/Dow...k_oil_film.pdf
http://202.228.55.2/technology/revie...91/e391016.pdf
http://www.ricardo.com/documents/dow..._predicted.pdf
http://books.google.ca/books?id=XjTa...ckness&f=false

And if you think 0W-20 is thin then how about this:
Shell Announces 0W-10 "Concept" Oil that Improves Fuel Economy 6.5 Percent! Motor oils classified as "fuel saving" typically improve fuel economy on the order of 0.5 percent or less over an ordinary motor oil. Shell's new "Concept" oil takes fuel economy improvements to a whole new level, provided the oil can be developed for widespread use.
The new experimental super thin 0W-10 oil was developed by research teams at Shell Global Solutions and Gordon Murray Design (GMD). The oil was tested in GMD's new T.25 city car using the new European driving cycle combined with urban driving cycles. The combined cycle driving yielded a fuel economy improvement of 4.6% compared to a 10W-30 motor oil, and a 6.5% fuel economy improvement in urban driving.
For more information about the GMD T.25 city car, visit www.gordonmurraydesign.com
No word yet from Shell as to when their new 0W-10 concept motor oil will be available to consumers, or if engine modifications will be necessary to use it (such as tighter bearing clearances to maintain adequate oil pressure). But the auto makers are certainly interested in any oil that could boost fuel economy significantly. Auto makers will have to meet tougher corporate average fuel economy standards by 2016 (37.8 mpg for cars and 28.8 mpg for light trucks)
http://www.shell.com/home/content/lu...lubricant.html

[brillo]

what oil is GC?

[Fly Guy]

German Castrol

[gmookher]

Originally Posted by rice_classic

Help me wrap this up then for oil nerd in all of us. Please elaborate on the place oil pressure has in this whole equation.


Some easy definitions for the folks at home when comparing Synthetic oils for use in your new car:

CentiStoke (cSt): Measurement of viscosity (at Cold 40C and Hot 100C), "tendency to flow" at a given temperature. "pouring a cup of honey"
CentiPoises (cP): Measurment of Absolute (Dynamic) viscosity, "ability of something to flow through the oil", the internal resistance to flow. Excellent for measuring shear. "stirring a cup of honey"


How about some comparisons of popular Syn brands:

Examples:

Mobile 1 0w-20
Viscosity, @ 100ºC, cSt 8.7
HTHS Viscosity, mPa•s @ 150ºC 2.7

Moblie 1 5w-30
Viscosity @ 100ºC, cSt 11.0
HTHS Viscosity, mPa•s @ 150ºC 3.1

Amsoil Signature Series 0w-20

Kinematic Viscosity @ 100°C, cSt 8.3

HTHS Viscosity, cP 2.8

Amsoil Signature Series 0w-30
Kinematic Viscosity @ 100°C, cSt 10.5
HTHS Viscosity, cP 3.1

Castrol Edge with Syn 0w-20
Kinematic Viscosity @ 100°C, cSt 8.65
HTHS Viscosity, cP 2.6

Castrol Edge with Syn 5w-20
Kinematic Viscosity @ 100°C, cSt 8.88
HTHS Viscosity, cP 2.6

Castrol Edge with Syn 5w-30
Kinematic Viscosity @ 100°C, cSt 10.7
HTHS Viscosity, cP 2.9


These comparisons tell me that Amsoil 0w-20 has excellent Kinematic viscosity (flow) and excellent level of shear protection (no pun intended).


To Mr Cowbell. I will need smbrm to elaborate here because...
I would say the cSt of the 0w-20 under track temps will be too low and the pressure of the oil between the bearings will be too low thus putting the HTHS rating to the test unnecessarily. This is why I'm asking smbrm to now add his take on pressure.

you forgot to put VI in perspective
subaru oe oil is 200ish
for when its over 100F out and I'm pushing it hard, see this stuff.
look at the cst @100c in post #6
still the VI of the oe subaru SM, and old toyota SM are hard to beat! Sorry, I'm an old fart, and know my oils

[bluesubie]

Originally Posted by gmookher

subaru oe oil is 200ish

Where did you get the VI of the Subaru oil? Was there a VOA showing the kinematic viscosity at 40C and 100C, or do you have a Product Data Sheet? Or are you going based on the Toyota 0W-20?

-Dennis

[rice_classic]

Originally Posted by gmookher

you forgot to put VI in perspective

Please then, put VI into perspective. I'm seeing a lubrication trend with you gm, that you like slippery stuff from Germany.


Edit:

smbrm already put VI into perspective to some degree right here:

However,those with higher HTHS viscosity should have higher viscosity(assuming all other operational aspects & fluid properties being the same) in connecting rod bearings and therefore should be able to carry more load(keep the journal and the bearing apart){the impact of any viscosity thinning not-with-standing}