Whos running Mobil 1 0w-40?

[W///]

Originally Posted by SenorFunkyPants

Here we are dealing with two similar oils...unless it takes significantly more heat to raise the temp of the 10W60 from ambient to 210F (very unlikely) than the Mobil 1 then the porridge water analogy doesn't really help.
To me its simple conservation of energy. You have a fixed amount of energy provided by the fuel. Some goes to heat up (amongst other things) the oil and some goes to accelerate the car. You can't have more heat going to heating up the oil AND more energy going to accelerate the car.
If the oil is heating up quicker then the car is accelerating slower.
Far more likely is the other way around (but likely not noticeable in a blind test).

I don't think anyone here is saying that lighter oil makes more power. And if it does, we are talking such a minuscule amount that it's probably not detectable on a street car. Maybe the fact that it's revvier means that the oil heats up quicker to a certain point, I don't know.

But this is not an 1+1=2 equation. You can't just say an combustion engine is energy of fuel in = heat + power. It's just not that simple of a model.

If you want to try to shoot holes into why people shouldn't use lighter oil, then by all means. You can question what long term effects it has on this and that, or how BMW AG doesn't approve it. Just can't use "it doesn't heat up any faster than 10W60" because that's false.

[Z K]

Originally Posted by W///

If you want to try to shoot holes into why people shouldn't use lighter oil, then by all means. You can question what long term effects it has on this and that, or how BMW AG doesn't approve it. Just can't use "it doesn't heat up any faster than 10W60" because that's false.

Exactly! The argument of whether 10w60 or 0w40 is "better" is debatable... but 0w40 faster warm up and easier revs is not questionable.

[apecush]

Originally Posted by e92zero

Oil pressure also runs lower so does that mean the oil is flowing through the system easier?

As pressure is essentially resistance to flow, that is correct.

[kawasaki00]

Originally Posted by e92zero

I know the theory of conservation of energy in an enclosed system. However, like the other poster has pointed out, an engine is much more complicated and I do not know all of it. I am just reporting what I am seeing. I was skeptical about it all also before hand. But the oil temp needle starts moving a good mile or so earlier than before on the same route. Oil pressure also runs lower so does that mean the oil is flowing through the system easier?

Flow goes up naturally because it is thinner, pressure only drops by a few lbs at idle because the pump is not on the bypass at 600 rpm. The thinner oil heats up faster, that's just the way it works. The water is up to temp long before the oil is in a wet sump motor, always has been always will be. How much faster is always going to be up for debate without testing but it will get up to temp faster if it is thinner.

[kawasaki00]

Originally Posted by apecush

As pressure is essentially resistance to flow, that is correct.

Only at idle though, once the rpms come up above 2k the pressure is the same when hot.

[e92zero]

Originally Posted by kawasaki00

Flow goes up naturally because it is thinner, pressure only drops by a few lbs at idle because the pump is not on the bypass at 600 rpm. The thinner oil heats up faster, that's just the way it works. The water is up to temp long before the oil is in a wet sump motor, always has been always will be. How much faster is always going to be up for debate without testing but it will get up to temp faster if it is thinner.

Yup, that's what I am seeing so far. Comparing to fresh tws, oil pressure is lower by about 4 lbs at idle. Cruising at 70 mph, oil pressure is lower by about 2 lbs. Engine feels smoother overall on the 0w-40. I have also noticed that oil pressure on used tws (at 7k miles) was lower by 2 lbs overall compare to when the tws was fresh. Will see how the 0w-40 does at the same change interval but don't think I will go back to tws.

I am noticing a few other things also but want to watch it for a bit longer before reporting to make sure I am not making things up or 'wishful' thinking.

[kenwelch]

Originally Posted by kawasaki00

Flow goes up naturally because it is thinner, pressure only drops by a few lbs at idle because the pump is not on the bypass at 600 rpm.

Not trying side track the discussion, but there have been several comments about pressures, flow, and oil pressure regulation.

The S65 M3 engine does not use a typical by-pass valve to regulate main engine oil pressure. Oil pressure is regulated by changing the volume output of the oil pump. There is a by-pass valve for the oil filter on the chance that the filter gets clogged or there is too much pressure drop across the filter surface.

From the technical manual:
“Two oil pumps are installed in the S65 engine; the oil return pump, which is driven via a gearwheel by a crankshaft, and the volume flow-controlled main oil pump, driven via
chain drive by the oil return pump. ………

As in the S85, the volume flow-controlled main oil pump is a hinged-valve oil pump with a feed capacity adjusted to suit the VANOS low pressure system.”


The E60 M5 manual has nice color pictures of the pump system including the “hinged-valve oil pump and description of it operation.
http://www.midia.nl/diversen/bmw/E60...te_Vehicle.pdf

More information about why this type pump is used in engine and automatic transmissions:
http://www.mahle.com/mahle/en/news-a...r-oil-pump.jsp

[SenorFunkyPants]

Originally Posted by kawasaki00

Flow goes up naturally because it is thinner, pressure only drops by a few lbs at idle because the pump is not on the bypass at 600 rpm. The thinner oil heats up faster, that's just the way it works. The water is up to temp long before the oil is in a wet sump motor, always has been always will be. How much faster is always going to be up for debate without testing but it will get up to temp faster if it is thinner.

Which is fine except "just the way it works" doesn't explain anything.
I don't mind if it warms up quicker or slower, if the engine loses more or less power by using a slightly more viscous oil. What I want to know is why - what are the physics that is directing the change. And it would have to be a sizable effect to be casually observable.

[Petros]

It may be related to flow. The less viscous oil flows better so it has more even heat distribution. The thicker oil doesn't flow as well, so there is a small volume of oil in the tiny spaces in the engine taking all the heat, while the bulk of the oil in the crankcase remains colder. That's just my hypothesis.

[StealYourFace]

Originally Posted by SenorFunkyPants

Which is fine except "just the way it works" doesn't explain anything.
I don't mind if it warms up quicker or slower, if the engine loses more or less power by using a slightly more viscous oil. What I want to know is why - what are the physics that is directing the change. And it would have to be a sizable effect to be casually observable.

The sun is yellow and the sky is blue. Just the way it works.

Don't get hung up on the why aspect.

Facts are always facts.

[chris719]

Originally Posted by SenorFunkyPants

Which is fine except "just the way it works" doesn't explain anything.
I don't mind if it warms up quicker or slower, if the engine loses more or less power by using a slightly more viscous oil. What I want to know is why - what are the physics that is directing the change. And it would have to be a sizable effect to be casually observable.

I think it's overall a little complicated. The oils may have different thermal conductivity to start with due to base stock formulation. You would actually think the heavier oil would warm first due to the additional energy required to pump it.

That might not be the case because the oil pump will be in bypass mode longer for the thicker oil. Also, there will be a different thermal gradient generated with the thinner oil that flows better as Petros said, it might be more "even".

[SenorFunkyPants]

Originally Posted by chris719

I think it's overall a little complicated. The oils may have different thermal conductivity to start with due to base stock formulation. You would actually think the heavier oil would warm first due to the additional energy required to pump it.

That might not be the case because the oil pump will be in bypass mode longer for the thicker oil. Also, there will be a different thermal gradient generated with the thinner oil that flows better as Petros said, it might be more "even".

As I understand it the M3's oil pump produces a volume controlled oil flow. So regardless of whether the oil is hot, cold, thick or thin it will strive to produce the same flow rate. Obviously this means the pump will consume more energy when the oil is thicker. Thicker oil also gives more drag between parts that have an oil film and there are extra frictional losses in the oil galleries as the oil is pumped through them. These losses cost a certain amount of horsepower, I'm hesitant to guess but for the sake of argument lets say they cost 5bhp. This 5bhp has to go somewhere and it pretty much all ends up being converted into heat.
So there is the quandary...the use of thicker oil generates more heat in the engine so logically it should heat that environment quicker than using a thinner oil. If there is physics that can explain how a system with less heat input (using a thinner oil) can heat up quicker then I would interested to know. Saying it just is, doesn't really help - at one time some owners thought air scoops gave more bhp and that a 20% under-drive pulley could give you 16bhp.
If I am going to be wrong I would like to know why...then I will know better for next time.

[W///]

Originally Posted by SenorFunkyPants

As I understand it the M3's oil pump produces a volume controlled oil flow. So regardless of whether the oil is hot, cold, thick or thin it will strive to produce the same flow rate. Obviously this means the pump will consume more energy when the oil is thicker. Thicker oil also gives more drag between parts that have an oil film and there are extra frictional losses in the oil galleries as the oil is pumped through them. These losses cost a certain amount of horsepower, I'm hesitant to guess but for the sake of argument lets say they cost 5bhp. This 5bhp has to go somewhere and it pretty much all ends up being converted into heat.
So there is the quandary...the use of thicker oil generates more heat in the engine so logically it should heat that environment quicker than using a thinner oil. If there is physics that can explain how a system with less heat input (using a thinner oil) can heat up quicker then I would interested to know. Saying it just is, doesn't really help - at one time some owners thought air scoops gave more bhp and that a 20% under-drive pulley could give you 16bhp.
If I am going to be wrong I would like to know why...then I will know better for next time.

But this is completely different than the air scoops and pulley. We are comparing butt dyno vs looking at an oil gauge right in front of you. Everyone in this thread that has switched to M1 has commented that car revs faster and oil heats up faster. I pointed out that it only heated up faster to 1/3 mark, then it acts similar to what TWS did, taking a while to reach 1/2 mark.

You argue that the heat is coming from the pump. I will state again that I'm not expert at this, but that doesn't make sense to me. That pump alone is not what brings oil up to 210F. That's a drop in the bucket compared to how much heat the engine itself produces. If that's the case, and we do agree that it is more free revving with lighter oil, then can't we say that the fact that there's freer revving = more movement = more heat?

Again, I think it's absolutely ridiculous to try to quantify how and why and where the heat is coming from because it's just not that simple. And frankly, who cares? It's multiple people (respected members at that) confirming that this is the case. IMHO, that was downfall of the bearing thread. Started off good, then turned into an 80 page thread just going back and forth. For once, we have facts, and not what ifs.

[Petros]

Regarding the oil pump being flow-driven, that is only true to a certain extent. There is a limit on the maximum pressure the pump can force the oil with. If the pump reaches that max pressure and the oil is still not reaching the ideal flow rate, the pump will not be able to compensate and keep the oil moving. I think I remember some members here who did install aftermarket oil pressure gauges found that the oil pressure during a cold start with TWS reaches the max allowable pressure before the bypass opens up.

[SenorFunkyPants]

Originally Posted by W///

Again, I think it's absolutely ridiculous to try to quantify how and why and where the heat is coming from because it's just not that simple. And frankly, who cares? It's multiple people (respected members at that) confirming that this is the case. IMHO, that was downfall of the bearing thread. Started off good, then turned into an 80 page thread just going back and forth. For once, we have facts, and not what ifs.

What facts? there are no facts. A bunch of people saying that they think their car warms up faster isn't facts its just speculation.
Human perception of events is incredibly unreliable. You are relying on your memory of how long the car took to warm up with TWS to compare with how long it takes to warm up with Mobil 1 without recollection or consideration for the numerous factors that affect the warm up rate at that time.
As regards the bearing thread, if enough people hadn't stood up and questioned the assertion that the bearing clearance was a cause of rod bearing failure then it would have been taken as fact...even now despite having now reached a conclusion that the clearance is almost certainly not too tight there is still a general feeling amongst the less informed that it is. If enough people say something enough times its starts to become accepted as fact. I know it annoys you and others that I'm arguing but IMO the physics say you are most likely wrong.
I'll tell you what....I'll ring Castrol tech support on Monday and ask them the question and I'll abide with what they say either way.
I meant to ring them today but have run out of time.

[SenorFunkyPants]

Originally Posted by Petros

Regarding the oil pump being flow-driven, that is only true to a certain extent. There is a limit on the maximum pressure the pump can force the oil with. If the pump reaches that max pressure and the oil is still not reaching the ideal flow rate, the pump will not be able to compensate and keep the oil moving. I think I remember some members here who did install aftermarket oil pressure gauges found that the oil pressure during a cold start with TWS reaches the max allowable pressure before the bypass opens up.

Isn't there a pressure relief valve only for the filter and not for overall oil pressure?

[apecush]

I think the physics supports a quicker warm up for the 0w40...

Lower viscosity = lower density = lower heat capacity = faster temperature increase for a given unit of heat input. Furthermore, lower viscosity means a thinner boundary layer on oil wetted parts, increasing the rate of heat transfer.

[W///]

Originally Posted by SenorFunkyPants

What facts? there are no facts. A bunch of people saying that they think their car warms up faster isn't facts its just speculation.
Human perception of events is incredibly unreliable. You are relying on your memory of how long the car took to warm up with TWS to compare with how long it takes to warm up with Mobil 1 without recollection or consideration for the numerous factors that affect the warm up rate at that time.
As regards the bearing thread, if enough people hadn't stood up and questioned the assertion that the bearing clearance was a cause of rod bearing failure then it would have been taken as fact...even now despite having now reached a conclusion that the clearance is almost certainly not too tight there is still a general feeling amongst the less informed that it is. If enough people say something enough times its starts to become accepted as fact. I know it annoys you and others that I'm arguing but IMO the physics say you are most likely wrong.

I drive the same commute to work everyday, so yes I know how my car is supposed to react. You'd be surprised how consistent it was with both oil. Note, I keep it under 3500 rpm's pretty much all the way to operating temp. As a mechanical engineer, if I can't read a oil temp gauge over the 23k miles I've put on this car, then I probably shouldn't be doing my job.

Secondly, I keep mentioning the rod bearings. There is a ton of speculation on that because it's inside the engine, so in this case I agree with you. Who the heck knows what's really going on? You can't "see" or "feel" the rod bearings. Oil temp is oil temp. It's not rocket science. Note, I never said it made more power or the car is faster, that's all feel with nothing to back it up. Oil temp is completely visual!

Your idea of physics is flawed and your experiment would look like this:
Cup of oil at room temp --> oil pump --> measure temp of oil that comes out of pump, then maybe 10W60 vs 0W40 comes out warmer. I don't know.

But an internal combustion engine is obviously not that crude of an equation is it? How can you argue that: "You are relying on your memory of how long the car took to warm up with TWS to compare with how long it takes to warm up with Mobil 1 without recollection or consideration for the numerous factors that affect the warm up rate at that time."
- but not consider that there are so many factors as to how oil initially heats up in the engine (outside the energy an oil pump takes to pump different oils)?

Anyway, I'm not going to carry further on. The only way you'll be truly satisfied with an answer is if you do an actual test yourself, which we all know you won't. And even if we did test and show what the rest of us that has run both oils already know (aka M1 heats up quicker), you'd still run TWS for other reasons anyway.

[kenwelch]

Originally Posted by Petros

I think I remember some members here who did install aftermarket oil pressure gauges found that the oil pressure during a cold start with TWS reaches the max allowable pressure before the bypass opens up.

This can't happen because there is no bypass valve to open up. See the documentation I provided in #249 above. The S65 engine uses a variable flow pump to control the oil pressure. There is not a bypass or dump style pressure regulator like many of the old days engine oil systems.

With increased pressure the S65 main oil pump reduces the flow rate to keep it within the approx. 5 bar max setting. There are pictures in the S85 document to help with the volume changes in the pump taking place.

[Billj747]

Thinner oil heats up quicker because it has a higher thermal conductivity than thicker oils. And water has a much higher thermal conductivity than oil which is why your water gets up to temp quicker than your oil.

[track_warrior]

im using 5w-40 in the winter but i switch back to 10w-60 tws or lubromoly in the summer.

[Petros]

Originally Posted by kenwelch

This can't happen because there is no bypass valve to open up. See the documentation I provided in #249 above. The S65 engine uses a variable flow pump to control the oil pressure. There is not a bypass or dump style pressure regulator like many of the old days engine oil systems.

With increased pressure the S65 main oil pump reduces the flow rate to keep it within the approx. 5 bar max setting. There are pictures in the S85 document to help with the volume changes in the pump taking place.

Perhaps so. I'll look into it. But the gist of what you say seems to agree with what I said, which is that there is a reduction in oil flow rate to avoid exceeding the maximum allowable pressure when the oil is cold and viscous.