One Dodge running 5W20 rewrites all the engineering texts in history ?

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So, I'm asking for a friend, but if I had a DeLorean that could time travel, would you recommend 0w-20 for the increased MPGs, given I'm driving for decades versus miles? Or, 15w-50 due to the extreme air resistance and engine load? If I went back in time to the 1700s, what type of whale oil is equivalent to 0w-20? 15w-50?

But seriously, there's a reason OEs sometimes call for different viscosity oil in cars used at the track. It protects better. But, given almost nobody runs at those loads and RPMs and engine computers control everything, a typical daily driver will live forever on 0w-20 (if that's its spec). Forever being 30 years or 300k miles before needing a rebuild if taken care of.

I don't have any papers or charts to back it up, just common sense.

With that said, I also don't think it matters if you put 0w-20 to 15w40 oil in your car. Just make sure it has a decent oil and it has oil.

And that, my friends, is my opinion with no facts or data. College football is on soon. Go watch!
 
Originally Posted by Linctex
My 2008 F150 has 170,000 miles and uses no oil - not one drop.

It has had 5w-20 Pennzoil from the quicklube place for the first 110,000 miles of its life.

I don't "get" CAFE... my truck gets E X A C T L Y the same fuel economy on plain ol' 10W-40 Pennz yellow bottle (it is what's in there right now, only $8 a 5qt jug at AutoZone last year) as it gets on full synthetic Peak 0W-20 (also an AutoZone clearance item)

I have tried both - there is no change in MPG at all.


Generally, the benefits require a lab to measure. If you recall when Mobil was advertising their AFE product line the claimed fuel economy gains were within a range that started below a percentage point. It doesn't mean the gain isn't there, simply that your typical driver can't properly measure it. Despite this gain being small, when applied over a large fleet, it adds up.
 
It all depends on the engine. Most all 2-valve iron head V8's will not be happy with 20 grade. Many small displacement OHC engines will. Many, if not most BMW engines will not. Putting 20 grade in my log splitter would be foolish in the extreme, or the tractors ...
 
Overkill: I like that bearing calculator you posted the link to. I played with it and saw that when using the default numbers, then changing the viscosity by x%, the load capacity changed by x%. I found that interesting because that is in contrast to the simplified relationship of minimum oil film thickness being a function of the square root of viscosity. Shannow's last 2 images in his reply to me also showed that relationship...thanks Shannow. I should note that when all I changed in that calculator was viscosity, I held film thickness constant, but in reality changing the viscosity would also change film thickness, which would in turn also change load capacity.

Let's move on to typical valvetrains. In most of them, they only operate in boundary, mixed, and elastrohydrodynamic (EHL). Increasing viscosity is likely to have what effect on resistance to motion (friction)? How about wear rate?
 
Originally Posted by JAG
Overkill: I like that bearing calculator you posted the link to. I played with it and saw that when using the default numbers, then changing the viscosity by x%, the load capacity changed by x%. I found that interesting because that is in contrast to the simplified relationship of minimum oil film thickness being a function of the square root of viscosity. Shannow's last 2 images in his reply to me also showed that relationship...thanks Shannow. I should note that when all I changed in that calculator was viscosity, I held film thickness constant, but in reality changing the viscosity would also change film thickness, which would in turn also change load capacity.

Let's move on to typical valvetrains. In most of them, they only operate in boundary, mixed, and elastrohydrodynamic (EHL). Increasing viscosity is likely to have what effect on resistance to motion (friction)? How about wear rate?


Yeah, I thought it was pretty neat. I'd rather have a spreadsheet version; something like the A_Harman index calculator I made and shared here, but obviously more complex. I believe that this calculator may not solve for MOFT, as it seemed to be a pre-populated constant. Perhaps a limitation of whatever program they've used to provide it.
 
Originally Posted by SatinSilver
Originally Posted by 4WD

Never (in several decades) had a GM leak or consume oil … never …


How about the Ford and Dodge?

Originally Posted by 4WD
On 20's:
Tahoe,
Z71 PU,
Fusion Hybrid,
Charger Pentastar …


The Dodge is only past 50k and does lots of short trips so it's changed at 4K with whatever 5w20 is on sale (looks like tar)
The Ford is past 100k and has used Mobil & Pennzoil 5w20's … no consumption from either … run it 6k or so …
I supply oil for a hand me down 2007 300 … at around 200k it is not needing top up oil … but maybe 1/2 Q when time to change … thats on M1 10w30 HM … been a good car really …
 
Originally Posted by OVERKILL
Originally Posted by JAG
Overkill: I like that bearing calculator you posted the link to. I played with it and saw that when using the default numbers, then changing the viscosity by x%, the load capacity changed by x%. I found that interesting because that is in contrast to the simplified relationship of minimum oil film thickness being a function of the square root of viscosity. Shannow's last 2 images in his reply to me also showed that relationship...thanks Shannow. I should note that when all I changed in that calculator was viscosity, I held film thickness constant, but in reality changing the viscosity would also change film thickness, which would in turn also change load capacity

Yeah, I thought it was pretty neat. I'd rather have a spreadsheet version; something like the A_Harman index calculator I made and shared here, but obviously more complex. I believe that this calculator may not solve for MOFT, as it seemed to be a pre-populated constant. Perhaps a limitation of whatever program they've used to provide it.

MOFT is supposed to be an input, but that input and some others say you must log in to change them. I couldn't find out where to log in. Having that as an input is good for designing a bearing but obviously if one wants to solve for MOFT, it is not the right tool.
 
Originally Posted by JAG
Originally Posted by OVERKILL
Originally Posted by JAG
Overkill: I like that bearing calculator you posted the link to. I played with it and saw that when using the default numbers, then changing the viscosity by x%, the load capacity changed by x%. I found that interesting because that is in contrast to the simplified relationship of minimum oil film thickness being a function of the square root of viscosity. Shannow's last 2 images in his reply to me also showed that relationship...thanks Shannow. I should note that when all I changed in that calculator was viscosity, I held film thickness constant, but in reality changing the viscosity would also change film thickness, which would in turn also change load capacity

Yeah, I thought it was pretty neat. I'd rather have a spreadsheet version; something like the A_Harman index calculator I made and shared here, but obviously more complex. I believe that this calculator may not solve for MOFT, as it seemed to be a pre-populated constant. Perhaps a limitation of whatever program they've used to provide it.

MOFT is supposed to be an input, but that input and some others say you must log in to change them. I couldn't find out where to log in. Having that as an input is good for designing a bearing but obviously if one wants to solve for MOFT, it is not the right tool.


thumbsup2.gif
 
Originally Posted by StevieC
Here in Canada fuel economy can drop by 20-30% in the winter



And that couldn't POSSIBLY be related to the winter blend gasoline to deal with the reduced vapor pressure at extremely cold temperatures, could it? It has to deal with the increased oil pump drive HP requirements because of the cold flow pumpability of oil?? Come on...
 
It's the traffic lol... I frequently drive a stretch of 75km of highway, my average mpg can vary by 30% on that stretch, depending on how busy an interchange on my way is. It's just a few km in front of the interchange that will produce the hit. In winter it's even worse as the traffic is even slower. Fixing the interchange would dramatically fix the mpg for everybody. Instead, we're going after 0.01 mpg through "fixing" the oil. This tells me that the "ecologists" are not genuine.
 
Originally Posted by SubieRubyRoo
Originally Posted by StevieC
Here in Canada fuel economy can drop by 20-30% in the winter
... It has to deal with the increased oil pump drive HP requirements because of the cold flow pumpability of oil??
That's thoroughly insignificant, compared to the other handicaps winter imposes. Do the math, using any plausible numbers you like, and you'll see.
 
Originally Posted by Gene K
I have zero qualifications to be in this thread but it seems to me the real question is what viscosity an engine actually needs. Then the question is how we go about getting it. I fail to see how the fact that we achieve it with a 20 Grade with a cooler over a 40 Grade without would be detrimental to the engine. I would think the more consistent viscosity with the 20 Grade setup would be beneficial but what do I know.

If the manifacturer fails to provide adequate temperature control for the application that's an engineering failure not a lube failure.

I would say all of this is worth considering. The Nissan/Infiniti 3.7 and the like have always been considered hard on the oil. Thicker oil has been one solution, as have oil coolers. There are people who specifically seek out oil cooling, because of the limp mode that can be activated with excessive oil temperatures. Of course, that's not a fault of the lube itself, per se. If a certain oil temperature 5w30 is too thin, then the temperature shouldn't be allowed to get there or a different grade should be specified. Of course, just blindly going up a grade while tracking won't prevent limp mode.
 
My question is still not answered, so I will post it again:

Let's talk about typical valvetrains. In most of them, they only operate in boundary, mixed, and elastrohydrodynamic (EHL) regimes. Increasing viscosity is likely to have what effect on the resistance to motion (friction)? What effect would it likely have on wear rate?
 
Originally Posted by JAG
My question is still not answered, so I will post it again:

Let's talk about typical valvetrains. In most of them, they only operate in boundary, mixed, and elastrohydrodynamic (EHL) regimes. Increasing viscosity is likely to have what effect on the resistance to motion (friction)? What effect would it likely have on wear rate?


http://www.threebond.co.jp/en/technical/technicalnews/pdf/tech09.pdf

Friction modifiers and anti-wear additives are mainly for those components that are mostly in boundary layer lubrication, such as cam lobes.
 
Originally Posted by JAG
My question is still not answered, so I will post it again:

Let's talk about typical valvetrains. In most of them, they only operate in boundary, mixed, and elastrohydrodynamic (EHL) regimes. Increasing viscosity is likely to have what effect on the resistance to motion (friction)? What effect would it likely have on wear rate?


Those operating in mixed may move into hydrodynamic, lowering wear rates. Increasing viscosity will increase fluid friction. As ZeeOSix noted, much of the rest relies on additives.
 
ZeeOSix: good paper. Friction modifiers certainly decrease total friction in those regimes.

Shannow: that is the paper that has the surface plot that I was looking for the other day! This time I bookmarked the link to it so I don't lose it again.

Overkill: thanks for answering. You got the wear answer correct. Your answer for friction is technically correct because you specified it in terms of fluid friction only, but I meant the question to apply to total friction (fluid + asperity contact friction). That's not your fault...I should have specified that in my question. In those lubrication regimes, increasing viscosity is likely to decrease total friction because it decreases asperity contact pressure and frequency of asperity contact. Even though the thicker oil itself has more fluid friction, the increase in fluid friction is less than the decrease in friction caused by the decreased asperity contact. Think of the Stribeck curve and where those regimes are. There, increasing viscosity will move the regime to the right and down on the friction curve. This is why there has been research into making engines have split oil sumps: one for the valvetrain with a thicker oil and the sump for the rest of the engine would have our typical oil viscosities. This would reduce overall friction, improve valvetrain wear, but be a more complicated engine. One of the papers I posted within the last year in the interesting articles forum tested an experimental engine that had the split sump. It gave reasonable improvements in friction.
Here is the thread about it: http://www.bobistheoilguy.com/forum...to-enhance-engine-efficiency#Post4837797
 
CR94, I was pointing out the ludicrous appearance of a claim that thick oils caused a 20-30% decrease in winter mileage in Canada, that was all. I get all the "real" mechanical losses that contribute to actual mileage losses in winter, in addition to the reduced energy of winter gasoline blends.
 
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