CAFE has Little to do with Motor Oil Viscosity Use

[TFB1]

Originally Posted By: CATERHAM

Install an oil pressure gauge and you'll learn first hand just how "unscary" running a 7cSt oil is in a 20wt application and even a 30wt app'. It's more difficult than you realize to actually run an oil that is "too light".

No thanks I'll pass on that one...

I have real oil pressure gauges in my hard runners, but I'm never going to believe pressure alone puts one in that safe zone, especially in a case of a boosted application that can produce fairly high HP numbers at low RPM...

 

[Bluestream]

Originally Posted By: Garak
Originally Posted By: Shannow
Hands up every country that has a CAFE ?

Hands up every country where xW-20s are common ?


Don't forget Canada.

We don't have CAFE, but our oil recommendations are almost always the same for the same vehicle sold in the U.S.


Actually we do use CAFE. The government here tries to keep Canadian automotive standards and requirements as close as possible to the US laws due to the highly integrated nature of the NA automobile industry. THe US CAFE standars are acculable to Canada, so there is no need to make another law.

 

[Bluestream]

Double post

 

[Nickdfresh]

Originally Posted By: aquariuscsm
.

So do you run a 0W2 oil in your car? If thinner is better,than thinnest must be best,right? DON`T START YOUR CAR!!!!!!! YOU`LL DESTROY IT!!!!!!!!!!!!


Why don't you make a few more ad hominem, strawman arguments?

Though, Honda is looking at a 0W-10 IIRC...

 

[A_Harman]

Originally Posted By: sciphi
GM hasn't gone to 20 weight oils since they're trying to simplify the job the lube tech needs to do at their dealers, among other things. Say a Sonic rolls in with a 1.8, a Equinox with the 3.0 DI V6 follows, a Silverado comes in with a 5.3, then a Cruze comes in with a turbo 1.4. Having 1 oil that will cover those disparate engines and their lubrication requirements lessens the chance of a $9/hour lube tech making a mistake, and an irate customer coming back.

GM needs a 30 weight to cover their turbo engines and their DI engines, both of which are hard on the oil. Getting 0.025 mpg better by going to a 20 weight when they might have to replace 1000 turbos is definitely not in their interests, or in the customer's interests.

Ehh, there are far more ways to skin a cat for CAFE than oil viscosity.


Just await a year or two, GM will be using 20-weights.

 

[SteveSRT8]

EVERYONE will be using 20w or even lighter.

And it will have everything to do with increasingly tough CAFE regulations and outrageous fines.

Note that CAFE is calculated by sales volume, thus higher volume cars will have the thinnest lubricants.

Also note that I am not a 20w hater, I actually regard it as a step forward in oil technology.

 

[Klutch9]

I think that people tend to WAY over complicate this whole thin/thick CAFE issue. Most cars now are specced to a 20-grade oil. Will that work fine with no adverse effects for 99.9% of people who buy those cars? Yep.

Now obviously, if you race/track your car, a thicker oil of some sort makes sense in order to maintain a proper operating temperature viscosity (amongst other things). Using a thicker oil to accomplish this usually makes the most sense, since it is an easier and cheaper alternative to adding an oil cooler and/or creating a bigger oil sump to reach the same end result.

The thing is, the target demographic who buys the vast majority of the vehicles sold does not drive their cars hard enough to merit 'thicker' oil. Because of this, 20-grade oils make perfect sense. A car will be specced for whatever oil will suit its INTENDED use.

 

[SwampSurvivor]

My cherokee has an oil pressure gauge. The engine has around 120k on it.

I'm tempted to swap in some 5w20 for my next oil change and see what the pressure is. Anyone else with an oil pressure gauge on an older engine want to give it a shot.

 

[A_Harman]

Originally Posted By: gpshumway
You're a smart man, Dr. Haas, but on this you're completely wrong. I've been told so directly by powertrain engineers within major auto makers. I obviously won't jeopardize my relationship with them to prove it to you in an open forum, so I will simply do a bit of math for you.

For every 0.1 MPG an auto maker misses their CAFE target, they owe the government $5 for every car they sell in a year. So an auto maker who sells two million cars and who's fleet is 0.2 MPG under the requirement owes the government $20 Million. This financial cost happens after the fact. Auto makers can also sell and trade their CAFE credits if they come in above their required average, meaning beating the CAFE target often translates directly to the bottom line.

It takes years to develop a new model and consumer preferences for one model or another are not predictable. Say Ford does a bang up job designing the new Taurus and takes lots of market share from GM and Toyota in this model cycle. Now also say they mess up on the Focus, and loose share to the Civic, Corolla and Cruze in the same cycle. They get nailed with a giant CAFE fine due to their product mix being different than they predicted, primarily due to factors outside of their control and decisions they made 3-5 years ago. Not exactly a corporate bean counter's dream come true.

20wt oil will save ~2% on fuel economy. For an auto maker selling two million cars which has a required CAFE average of 24 MPG, using 20wt oil could potentially be worth $50 Millon per year. Given the financial health of many auto makers and the extent to which they wring every nickel of production cost out of their designs, do you really think they're going to leave $50M on the table?

In normal usage 20wt oils work well, their downside is not wear, it's a smaller thermal safety margin against failure of the hydrodynamic film in the bearings. You need only look at the oil requirements of street cars which are expected to see high oil temperatures on a racetrack to know that. These models are generally very low volume, and therefore have little impact on CAFE. But then you already know all this.


This is one of the best posts I have read on BITOG.

 

[AEHaas]

Somehow I doubt that the automotive manufacturers missed the CAFE requirement by 0.2 MPG. They tripled the fuel economy of there fleet using all the other advancements. It just makes no sense to me that they minimized research in all other areas and concentrated money and efforts to get 0.2 more MPG based on motor oil.

I believe that the use of thinner oils is a natural evolution and that as additive components progress so will the use of thinner and thinner oils. Greater flow, better cooling, easier starting and less wear will be some of the benefits for the basic passenger car.

I also think that the notion was in part brought to the foreground by the automotive racing sport. Many advancements in passenger cars have come directly out of racing car developments. In Formula 1 the engines were used only once. Now they are required to be used 2 or 3 times and still be just as able to win a race as a new engine. There are no fuel stops in Formula 1. You race on the one tank of gas you started with. Fuel economy actually plays a role now in racing. We are planning on going to the Formula 1 race in Texas later this year with Ferrari. Maybe I can pick up a few tips.

aehaas

 

[SteveSRT8]

Originally Posted By: A_Harman
Originally Posted By: gpshumway
You're a smart man, Dr. Haas, but on this you're completely wrong... These models are generally very low volume, and therefore have little impact on CAFE. But then you already know all this.


This is one of the best posts I have read on BITOG.


And it is absolutely correct. As I have stated before in other threads, the CAFE fines are huge, and thus high volume cars will get EVERY tweak they can for every drop of fuel savings.

 

[AEHaas]

Why do you think Chevy and others are still using 30 grade oils and possibly ? giving up millions in CAFE fees? I do not understand.

Also, Honda and Toyota have a much higher MPG average as their cars are smaller on the average (compared to Ford or Chevy). Yet they are working on a 10 grade oil? Is Honda paying huge fees that a 0.2 percent increase in MPG is needed. I do not understand.

aehaas

 

[doitmyself]

Originally Posted By: AEHaas
Somehow I doubt that the automotive manufacturers missed the CAFE requirement by 0.2 MPG. They tripled the fuel economy of there fleet using all the other advancements. It just makes no sense to me that they minimized research in all other areas and concentrated money and efforts to get 0.2 more MPG based on motor oil. aehaas

Nobody here said that they minimized research in other areas. 20wt. was one of the easy, additional ways (along with the other improvements) to initially meet CAFE.

RE: CAFE credit trading (for being above the CAFE standards)
"Calculations using official CAFE data, ....... Toyota can use the provision to avoid or reduce compliance on average by 0.69 mpg per year through 2020,

* Hyundai (1.01 mpg),
* Nissan (0.65),
* Honda (0.83 mpg),
* Mitsubishi (0.13 mpg),
* Subaru (0.08),
* Chrysler (0.14 mpg),
* GM (0.09 mpg), and
* Ford (0.18 mpg) also benefit.

The estimated value of the CAFE exemption gained by Toyota is $2.5 billion; Honda’s benefit is worth $0.8 billion, and Nissan’s benefit is valued at $0.9 billion in reduced CAFE compliance costs. Foreign companies gained $5.5 billion in benefits compared with the $1.8 billion that went to the Detroit Three." Source: Wikipedia (ya, I know, don't flame me)

So, yea it appears there are $ to be save from tiny increases.

Dr. AEHaas, you seem to indicate that the move to 20W was for engine benefits/longevity, NOT CAFE. Yet, the overwhelming evidence presented here is that the INITIAL move to 20W WAS due to CAFE regulations:

Originally Posted By: GMorg
I thought that oil viscosity labels on the the oil cap was ORIGINALLY required by the Feds because the manufactures negotiated this label as a way to help ensure that customers were generally using the same oil viscosity that was used to establish CAFE parameters. My understanding was that the Feds were concerned that the manufacturers were using an oil that customers did would not use and that the manufacturers' data would not be applicable to the real world. Fractions matter given the volume of vehicles sold.

and:
Originally Posted By: Bluestream
According to Ford the 5W20 Is for MPG:

Answer from Ford:
Ford Motor Company has an obligation to the EPA to ensure all of our customers have access to this new oil


Note that Ford did not say they are developing this oil for increased engine performance and longevity. The EPA oversees CAFE, not engine wear.

Why are you arguing against what the some auto companies are saying?

Originally Posted By: AEHaas
Why do you think Chevy and others are still using 30 grade oils and possibly ? giving up millions in CAFE fees? I do not understand.aehaas


Good question. Why WOULD they choose not to save many millions of dollars.

 

[gpshumway]

Originally Posted By: Bluestream
Originally Posted By: gpshumway
20wt oil will save ~2% on fuel economy.

Can you quote a source for this, or did you make it up?


It's straight from the ILSAC specification for resource conserving oil. You can download the spec HERE .

The testing procedure is ASTM D7589. The actual spec for virgin xW-20 is 2.6% minimum.

I realize we all come off a bit abrupt in prose on the internet, but you could have done a little searching before accusing me of making it up.

 

[JOD]

Originally Posted By: AEHaas


Also, Honda and Toyota have a much higher MPG average as their cars are smaller on the average (compared to Ford or Chevy). Yet they are working on a 10 grade oil? Is Honda paying huge fees that a 0.2 percent increase in MPG is needed. I do not understand.

aehaas


Maybe this will help you understand: http://www.youtube.com/watch?v=OAYkigNbzgs

Honda's principle chemist makes it very clear that the push to a 10 grade oil is because they recognize there are FE gains to be made with even thinner oils.

As pointed out in the post above mine, ALL gains end up being a net benefit for the OEM's, and it's all additive. Just because cars have lower CdA, more efficient drive trains etc, doesn't mean that you can ignore gains from different lubrication strategies. It also doesn't necessarily mean that these lubrication strategies equate to more wear.

 

[buster]

Fact:

1. A move to low viscosity oils is primarily due to greater fuel economy. CAFE.

2. Low viscosity oils do not necessarily sacrifice protection. Advancements in technology and formulating have helped create robust 20 grade oils.

3. Engines that call for 20 grade oils do not have premature wear issues.


I don't see what all the fuss is about? Engines can run on multiple viscosities.

 

[Oil Changer]

Originally Posted By: buster
Engines can run on multiple viscosities.


Technically, don't they always?

 

[gpshumway]

Originally Posted By: AEHaas
Why do you think Chevy and others are still using 30 grade oils and possibly ? giving up millions in CAFE fees? I do not understand.


Because it's a trade off between safety margin, logistics cost, warranty cost, and financial benefits, just like most engineering decisions made within a for-profit corporation. Each auto maker is free to balance the trade offs as they see fit. The 1.4l turbo in the Cruze takes 5w30 probably because its harder on oil than the 1.8l in the Civic which uses 5w20. The Cruze achieves it's fuel economy through different means.

Originally Posted By: AEHaas
Also, Honda and Toyota have a much higher MPG average as their cars are smaller on the average (compared to Ford or Chevy). Yet they are working on a 10 grade oil? Is Honda paying huge fees that a 0.2 percent increase in MPG is needed. I do not understand.

aehaas


It's not 0.2% it's 2%, which equates to ~0.5 MPG for a given maker's fleet.

As I and others mentioned before, CAFE credits can be banked, traded or sold. The Wikipedia link indicates Toyota benefits to the tune of $ Billions from their CAFE performance.

 

[CATERHAM]

Originally Posted By: TFB1
Originally Posted By: CATERHAM

Install an oil pressure gauge and you'll learn first hand just how "unscary" running a 7cSt oil is in a 20wt application and even a 30wt app'. It's more difficult than you realize to actually run an oil that is "too light".

No thanks I'll pass on that one...

I have real oil pressure gauges in my hard runners, but I'm never going to believe pressure alone puts one in that safe zone, especially in a case of a boosted application that can produce fairly high HP numbers at low RPM...

As Shannow alluded, it's not the "oil pressure" that provides the protection. You just need enough oil pressure to deliver oil to every part of the engine in a timely manner. It is the oil's viscosity that provides the protection.
What an OP gauge actually measures is the back pressure or resistence to the oil flow through the bearings et al. The higher the reading on the gauge the higher the oil's viscosity, that's why an OP gauge is an effective viscometer.
For example, if 60 psi at elevated rev's corresponds with the optimum minimum operational viscosity in an engine then that can be acheived with all available oil grades but at different oil temperatures.
With a 30wt oil you may need an oil temp' of 120C to register 60 psi on your OP gauge. Below that temp' the OP will be progressively higher.
With a 40wt oil it may take 135C temp's to get 60 psi and perhaps 150C with a 50wt oil.
With a 20wt oil it may only take 105C to get 60psi but if your bulk oil temp's rarely gets above 95C you may never see OP below 70psi.
A 10wt oil may give you 60 psi at 95C and in this hypothetical example that could be the optimum oil grade to use.
A 5wt oil may give you 60 psi at only 85C and that would still be fine, even ideal if the operating conditions where such that the oil temp's were unable to get any higher; i.e., short trip winter use or in a race car as a qualifying oil.

So in the above example, even if you rarely see an OP reading below 70psi (again at elevated rev's) you may not want to run anything lighter than a 20wt oil even if it was available. The extra viscosity that the higher OP reading is a proxy for could be considered a safety margin to deal with the unexpected, such as oil shear, fuel dilution and higher than normal oil temp's.
Since most vehicles don't have an OP gauge it's best to rely on the OEM's oil grade recommendation as they have already factored in the viscosity safety margin.

 

[friendly_jacek]

Originally Posted By: buster
Fact:

1. A move to low viscosity oils is primarily due to greater fuel economy. CAFE.
[...]
I don't see what all the fuss is about? Engines can run on multiple viscosities.


The fuss is about OP authoritatively stating "CAFE has Little to do with Motor Oil Viscosity Use" and provided no facts to back it up.