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Discussion Starter #1
I thought I better start a new thread for this, since my last got away from the VCM topic I started it for. This one is absolutly all about oil and MPG!

From a Honda publication I didnt realize I had, dated April 21st, 2009 by Jeff Jetter of Honda R&D. This explains why I'm not seeing any real world decrease in MPG. Per Honda 1.0L test bench engine, 0w-20 is only 1.5% more efficient than 5w-30 in high efficiency, low friction engines.


So over 100,000 miles (or lets say 6 years as short average), 1.5% = 1500 miles.
1500 miles @ 20mpg and $4 per gallon gas = $300 savings

That's $50 per year savings over 6 years @ 20mpg, as a HIGH end savings estimate.

I'm not saying do not run 0w-20, actually the contrary in most cases. What I am pointing out, is the savings and increased efficiency isnt as high as people assume.

It also becomes obvious most engines are not "dragged down" by running Xw-30 or Xw-40 oils.


 

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Well, since you asked, its a 1.0L on a test stand, not a V6 in a 4k lbs truck. Do you think the 1.0 has VCM? HA HA. I could go for an extra $300...
 

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Maybe you could find the mpg difference between 5W20 that Honda recommended before it changed to the 0W20 recommendation for newer series engines.
 

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As you mention, I think your estimate is "high end" and real-world savings vs. steady-state running on a test stand would be less. $50 a year, in the world of incremental fuel savings, seems pretty significant to me and likely discourages owners from using heavier-weight oils, which is exactly what Honda wants.

Honda was one of the pioneers in the push to lighter-weight oils for fuel economy reasons and had to jump through a lot of regulatory humps to get it approved - in a negotiated deal, they had to agree to be very adamant in their service literature to essentially require, rather than given owners choices based on climate (see below), the lighter-weight oil in order to be able to use it during the EPA mileage tests. (This doesn't prevent many dealers from routinely using cheaper 5W-30 bulk oil for oil changes, BTW.) At the time of the push, around 2000 if I recall correctly, Honda was trying to drive their CAFE number higher to be seen as a leader by the government in the push towards higher efficiency.

I think some engine protection probably got sacrificed in the push and my belief is that if you want the maximum possible engine life, especially if you live in a hot climate or drive the car hard, you probably are better off with 5W-30. But I have no hard data to back up this claim, just observations of how regulatory processes sometimes drive engineering. There is certainly nothing "wrong" with using the recommended oil. But I use 5W-30 in my 2006, partly because I live in a pretty temperate climate; if I lived in Duluth, I'd run 5W-20 or 0W-20 and if I lived in Corpus Christi, I'd probably run 10W-30.

There is no technical reason we shouldn't still be given oil choices based on climate similar to the charts below (the first from a 2013 Elantra GT, the second from a 2012 Yamaha motorcycle.) From a steady-state, minimize engine wear standpoint, generally you want the narrowest range of viscosity with the heaviest-weight oil that meet the temp range you expect to operate the car in. Conversely, for best fuel economy, you want the lightest-weight oil that meets the temperature range of operation. The reason we're not given much choice anymore is regulatory, not technical.





- Mark
 

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Discussion Starter #5
As you mention, I think your estimate is "high end" and real-world savings vs. steady-state running on a test stand would be less. $50 a year, in the world of incremental fuel savings, seems pretty significant to me and likely discourages owners from using heavier-weight oils, which is exactly what Honda wants.

Honda was one of the pioneers in the push to lighter-weight oils for fuel economy reasons and had to jump through a lot of regulatory humps to get it approved - in a negotiated deal, they had to agree to be very adamant in their service literature to essentially require, rather than given owners choices based on climate (see below), the lighter-weight oil in order to be able to use it during the EPA mileage tests. (This doesn't prevent many dealers from routinely using 5W-30 bulk oil for oil changes, BTW.) At the time of the push, around 2000 if I recall correctly, Honda was trying to drive their CAFE number down to be seen as a leader by the government in the push towards higher efficiency.

I think some engine protection probably got sacrificed in the push and my belief is that if you want the maximum possible engine life, especially if you live in a hot climate or drive the car hard, you probably are better off with 5W-30. But I have no hard data to back up this claim, just observations of how regulatory processes sometimes drive engineering. There is certainly nothing "wrong" with using the recommended oil. But I use 5W-30 in my 2006.

There is no technical reason we shouldn't still be given oil choices based on climate similar to the charts below (the first from a 2013 Elantra GT, the second from a 2012 Yamaha motorcycle.) The reason we're not is regulatory, not technical.





- Mark

I couldnt agree more.

To the question above, there is no comparison between 0w-20 and 5w-20 at operating temp. They are equals in that respect. Remember w=Winter (32f) = not weight.

To throw in more technical info, by actual measured vaules, some 0w's are actually within 5w's range. Some refer to them as "heavy zero's". But this is truely meaningless in the real world.
 

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Temperature charts don't mater much in a well designed engine with sufficient cooling capability, since the internal temperatures are stable and not significantly affected by ambient temperature.
 

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Discussion Starter #7
Temperature charts don't mater much in a well designed engine with sufficient cooling capability, since the internal temperatures are stable and not significantly affected by ambient temperature.
True. But read his post more carefully. He was only making a point that from a technical standpoint, there are many other options. You find more options when you leave the automotive world because there arent so many politics involved...for now.
 

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Temperature charts don't mater much in a well designed engine with sufficient cooling capability, since the internal temperatures are stable and not significantly affected by ambient temperature.
They sure as heck matter at cold startup.

And even in steady-state running, underhood temps are much higher in high ambient temperature conditions. The entire engine isn't uniformly at the temperature of its water cooling system; the temperature of a cam lobe, for example, in steady-state hot conditions is much higher than in cool conditions. The water jacket of a car engine is designed to keep critical internal parts of an engine at a steady temp, but the rest of the engine will rise/fall in temp with different ambient temps; in a sense, a water-cooled engine is only partially water-cooled - the rest is air-cooled with no thermostat. Finally, most modern cooling systems, for reasons of fuel economy and drag reduction, are not sized large enough to keep an engine at a uniform temperature under worst-case conditions - they allow a considerable excursion to higher overall temps in high-load/hot-temp conditions.

BTW, because consumer don't like to see temp gauges creeping up, many are designed to stop rising when they hit mid-scale unless the engine overheats. This hides the normal rise in coolant temps that occurs in heavy-load/high-temp conditions. This essentially turns the temp gauge into an idiot light at the upper end. (I don't specifically know if the Pilot is this way.)

- Mark
 

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Yes, I agree about cold start up, but the internal temps (even on the top side), while they do follow load don't follow ambient near as much as in bygone days.

Add a independent temp gauge to a modern Honda and you will see just how stable these engines are.

They also have more reserve cooling as can be shown by the fact that no one even worries about shutting off the AC on long up hill stretches any more.
 

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Interesting thread. I'm wondering why on earth I have 0W20 in the crankcase here in Florida as summer approaches.
 

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Discussion Starter #11
Interesting thread. I'm wondering why on earth I have 0W20 in the crankcase here in Florida as summer approaches.
Well, the main point is, you have choices. While 0w-20 is recommended, its not required and the savings is very slim. That said, why not run it?
<O:p</O:p
0w-20, which are all synthetics, is approved for use in all temp ranges by every major manufacture. And I haven’t seen any UOA's or other data that says 0w-20 isnt protecting engines recommended to run it. (Its been out for a long time now, we'd find reports out there if something was happening.)

So, for normal driving, its worth the possible savings and cold start up benifit, unless you find reason (or personal feelings) not to run 0w-20.
<O:p</O:p

For me, my "feeling" is that I prefer slightly higher viscosity oil in the Pilot. I "feel" better towing with it, my perception/feel of VCM activation is better and I havent realized any MPG decrease at all. In my Accord, well thats another story. I have no reason not to run 0w-20 or 5w-20.
 

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I'm running 0W-30 and may go to 0W-40 next change for the SoCal summer.

FWIW, the now-vintage recommendation was to find the thinnest oil you could find that would let you maintain hot idle oil pressure. Thicker means more initial cold-start wear, plus thicker doesn't cool as well. That's still the 0W- or 5W- or 10W- part. The other number is for --equivalent-- film strength at 100ºC oil temp. So a -20 has the same film strength as a single-grade straight 20-weight would at 100ºC. Going to a -30 or even a -40 does not give you a thicker oil as the temperaure increases, it just gives you the higher film strength at temperature. It's still 0W- or 5W- viscosity or whatever.

----

To the OP's savings estimate: Your calcs are great --IF-- oil-related engine friction is the only drag factor to consider. It's really just a fraction of total friction loss that includes aero drag and all the other friction/drag losses in the driveline. In the end, IMHO anyway, the potential savings seen by using 0W-20 vs. 0W-30 or 40, or even 5W- or 10W lubricants is way less than $300 in fuel savings. I don't recommend that anybody go out and change to something that's way different than what Honda suggests just on a whim or some "expert" advice from me or any other self-proclaimed internet oil gurus (who may also use the name "Bob"...). I get to make my own decisions based on the normal use pattern for my own car though. YMMV and all that.
 

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Discussion Starter #13
FWIW, the now-vintage recommendation was to find the thinnest oil you could find that would let you maintain hot idle oil pressure. Thicker means more initial cold-start wear, plus thicker doesn't cool as well. That's still the 0W- or 5W- or 10W- part. The other number is for --equivalent-- film strength at 100ºC oil temp. So a -20 has the same film strength as a single-grade straight 20-weight would at 100ºC. Going to a -30 or even a -40 does not give you a thicker oil as the temperaure increases, it just gives you the higher film strength at temperature. It's still 0W- or 5W- viscosity or whatever.



.

You bring up some debatable points here, and one ill fact.

Between 0w and 5w (again W being winter @ 32f or 0c) many other these oils cross over in actual cst measure viscosity, so the cold start comparison is splitting hairs. Over 32f, the that W number means less and less.

Now the ill facts highlighted above is that at 212f/100c, the second number is absolutely a viscosity rating. The numbers are derived from straight weight oils at temperature as you say, but your continuation is wrong.

Examples:

SAE30 straight weight at 212f will be within the same viscosity range as an Xw-30 at 212f.

At 32f, a 5w-XX motor oil will be only as thick as an SAE5 straight weight.

And with the thicker oil, often comes higher film strength. You dont get higher film strength for free, it typically comes with higher viscosity oils.


Anyone with an air cooled motorcycle engine will tell you thicker oils are better than thin, and cooling is a huge part of that debate. 5w-40 is very common, 15w-50, and 20w-50 are also common in V-twins. And because gear cases (other than HD's) often run in the same oil the engine does, oils are most often in the Xw-40 range to hold up to the severe oil shear.
 

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Perhaps I 'splained it poorly. A 5W-50 is not thicker at 100ºC than it is at 0ºC.
 

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Anyone with an air cooled motorcycle engine will tell you thicker oils are better than thin, and cooling is a huge part of that debate. 5w-40 is very common, 15w-50, and 20w-50 are also common in V-twins. And because gear cases (other than HD's) often run in the same oil the engine does, oils are most often in the Xw-40 range to hold up to the severe oil shear.
Thicker oils don't flow as well as thinner oils, so they don't cool as well.
Poorer cooling ⇒ higher temperatures ⇒ the need for thicker oil ⇒ poorer cooling.

Conversely, thinner oil cools better which reduces the need for thicker oil.

Another issue, with using thinner oils in those motorcycles where the engine and transmission share a common oil supply, is that the friction modifiers, more commonly found in thinner oils, can result in clutch slippage.
 

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Discussion Starter #17
Thicker oils don't flow as well as thinner oils, so they don't cool as well.
Poorer cooling ⇒ higher temperatures ⇒ the need for thicker oil ⇒ poorer cooling.

Conversely, thinner oil cools better which reduces the need for thicker oil.

Another issue, with using thinner oils in those motorcycles where the engine and transmission share a common oil supply, is that the friction modifiers, more commonly found in thinner oils, can result in clutch slippage.
I did say "cooling was a huge part of that debate". And yes, JASO MA/MA2, or at least non "energy conserving" oils for use with with wet clutches.

Yes, by definition thin fluids cool better than thick. But try selling that to many HD owners. HDC doesn't offer any oils thinner than 10w-40, and they go up to SAE60. Most common is 20w-50. These engines need very high film strength and strong boundary layers well ahead of "thin oil" cooling. AIR is their primary cooling system. Oil is secondary, and sometimes a close second when an oil cooler is included...but never primary.

Some who enter the debate claim the high viscosity oils run cooler. And that may very well be because they do not transfer heat as fast, but we're splitting hairs in most cases in that regards. They see lower oil temps and believe it wont break down as fast during severe duty, like parades for example. Some engines will shut down shut down one cylinder, or shut off all together when engine heat is excessive, but the thicker oils generally hold up.

Well, we're off topic as I brought up motorcycles. My bad. It's in my blood, and even my name "RinconVTR". Cant help it... :18:
 

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most people will probably find this very interesting, I certainly wish I had found it sooner.


your oil's weight is nothing more than its resistance to flow, whether that's pouring it down a slide and letting gravity bring it down to the ground OR having a gear pump force it through channels and bearings throughout an engine.

the real protection of an oil comes down to one thing... the additive package that is blended with the base stock. that is what actually helps protect the metal to metal contact from friction
 

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