dnewton3
Staff member
One thing people so very often don't understand about "heat" when it comes to turbos is the concept of thermal transfer. People typically are concerned about coking of the oil; I can understand that.
But "heat" (as in "gosh it's got two turbos; it must get really "hot") really isn't descriptive enough for the situation.
Thermal transfer is a much more descriptive way to look at this. And that comes down to design criteria of not only the lube, but also the lube system itself.
On needs to start with this ....
what does the oil do in the turbo? There are different designs. While all typically us oil to lube the bearings, some use the oil also to cool the turbo, while others actually can use coolant for cooling. So that's the first consideration.
If the turbo does indeed use oil for cooling in addition to lubing, then there's a question of proper or improper design. I'm not going to say one is "better" than another, in design. What I'm stating is that success or failure can be simply judged by results, not debate on theory. If the system does not coke the oil, and the turbo lasts a nice long time, then that specific design must be satisfactory for the intent of longevity.
And that brings me to the concept of thermal transfer. As long as the design has enough volumetric flow to:
a) do the job requested
b) not be harmed in the process
then the lube system (viewed as the lube itself and the mechanical pump and circuits) is succeeding.
I've used this example before, but it's time to bring it out again. Think of a candle and your fingers.
If you quickly pass your fingers over a candle, you'd likely feel little if any heat. As the thermal energy rises, some of it is absorbed into your fingers, but certainly not enough to harm your skin, and not enough to really greatly alter the total BTUs that physically move the air in it's upward path.
Now if you were to slow your hand down a bit, more BTUs go into your fingers; you might feel some pain and get perhaps a first-degree burn (redness but no blisters). Because some energy went into your fingers, the total BTU energy that heated the air to make is rise was lessened by that amount.
If you would hold your hand steady over the flame tip, it would not be long before the flesh suffered third degree burns (destroyed flesh; significant dermal damage). Also, very little heat energy would be in the air because most went into your fingers!
In those three examples, the flame tip energy never changed; it continued to produce the same amount of BTUs. But the transfer went into a different area, and the surrounding environment saw a significant shift in the thermal transfer.
And so it goes with oil in a turbo, especially with oil-cooled turbos. As long as the engineers designed the "system" to have a lube that can survive the thermal transfer rate, and the lube flows are great enough (truly measured in volumetric flow), then the lube will never be scorched because it can carry away "heat" with no issues whatsoever. Rather than a small amount of lube taking away all the heat, you want a large amount of oil taking away just a bit of heat, but the cumulative effect satisfies the safe operation of the engine.
So when folks get all excited about "turbo" heat, I just cannot fall into that band-wagon. In my opinion, it is MUCH more dependent upon the system design, rather than if some lube is one-tenth under-rated for the HT-06 criteria.
It's clear to me that engines like the Dmax have a VERY good lube system design; UOAs show the engine does not care about lube selection and they almost never come back coked/cooked.
Time will tell if the EcoBoost has a "good" design for the two turbos. But what I see in this UOA (and others) is that the oil really isn't taking a heat beating; it's getting a fuel soaking. And as long as you OCI frequently enough, keeping the fuel at 5% or less, the UOA wear results are telling us the engine can live with the fuel (at least in the short term). So that is why I say that dino lubes that meet Ford spec (such as the ones I listed previously) are probably every bit as capable as any syn in these circumstances. Moderate OCIs are showing us that the turbos don't seem to hurt the oil in the Ecoboost, and the wear is in control, even with 5% fuel.
So again, I see that under these conditions (short-to-moderate OCIs) I don't think the EB engine is that hard on oil, despite the fuel. The results (and you know how I love results more than inputs) are showing us that the conditions are not as "tough" on the oil as many would profess them to be. And I suspect a dino oil under these circumstances would do just as well, because the fuel isn't hurting wear and the heat isn't great enough to heavily shift into coking.
As I said before, the 1+ year is a good start, but several years of data will be more conclusive. But these preliminary UOAs over this last year are showing my points to be valid.
But "heat" (as in "gosh it's got two turbos; it must get really "hot") really isn't descriptive enough for the situation.
Thermal transfer is a much more descriptive way to look at this. And that comes down to design criteria of not only the lube, but also the lube system itself.
On needs to start with this ....
what does the oil do in the turbo? There are different designs. While all typically us oil to lube the bearings, some use the oil also to cool the turbo, while others actually can use coolant for cooling. So that's the first consideration.
If the turbo does indeed use oil for cooling in addition to lubing, then there's a question of proper or improper design. I'm not going to say one is "better" than another, in design. What I'm stating is that success or failure can be simply judged by results, not debate on theory. If the system does not coke the oil, and the turbo lasts a nice long time, then that specific design must be satisfactory for the intent of longevity.
And that brings me to the concept of thermal transfer. As long as the design has enough volumetric flow to:
a) do the job requested
b) not be harmed in the process
then the lube system (viewed as the lube itself and the mechanical pump and circuits) is succeeding.
I've used this example before, but it's time to bring it out again. Think of a candle and your fingers.
If you quickly pass your fingers over a candle, you'd likely feel little if any heat. As the thermal energy rises, some of it is absorbed into your fingers, but certainly not enough to harm your skin, and not enough to really greatly alter the total BTUs that physically move the air in it's upward path.
Now if you were to slow your hand down a bit, more BTUs go into your fingers; you might feel some pain and get perhaps a first-degree burn (redness but no blisters). Because some energy went into your fingers, the total BTU energy that heated the air to make is rise was lessened by that amount.
If you would hold your hand steady over the flame tip, it would not be long before the flesh suffered third degree burns (destroyed flesh; significant dermal damage). Also, very little heat energy would be in the air because most went into your fingers!
In those three examples, the flame tip energy never changed; it continued to produce the same amount of BTUs. But the transfer went into a different area, and the surrounding environment saw a significant shift in the thermal transfer.
And so it goes with oil in a turbo, especially with oil-cooled turbos. As long as the engineers designed the "system" to have a lube that can survive the thermal transfer rate, and the lube flows are great enough (truly measured in volumetric flow), then the lube will never be scorched because it can carry away "heat" with no issues whatsoever. Rather than a small amount of lube taking away all the heat, you want a large amount of oil taking away just a bit of heat, but the cumulative effect satisfies the safe operation of the engine.
So when folks get all excited about "turbo" heat, I just cannot fall into that band-wagon. In my opinion, it is MUCH more dependent upon the system design, rather than if some lube is one-tenth under-rated for the HT-06 criteria.
It's clear to me that engines like the Dmax have a VERY good lube system design; UOAs show the engine does not care about lube selection and they almost never come back coked/cooked.
Time will tell if the EcoBoost has a "good" design for the two turbos. But what I see in this UOA (and others) is that the oil really isn't taking a heat beating; it's getting a fuel soaking. And as long as you OCI frequently enough, keeping the fuel at 5% or less, the UOA wear results are telling us the engine can live with the fuel (at least in the short term). So that is why I say that dino lubes that meet Ford spec (such as the ones I listed previously) are probably every bit as capable as any syn in these circumstances. Moderate OCIs are showing us that the turbos don't seem to hurt the oil in the Ecoboost, and the wear is in control, even with 5% fuel.
So again, I see that under these conditions (short-to-moderate OCIs) I don't think the EB engine is that hard on oil, despite the fuel. The results (and you know how I love results more than inputs) are showing us that the conditions are not as "tough" on the oil as many would profess them to be. And I suspect a dino oil under these circumstances would do just as well, because the fuel isn't hurting wear and the heat isn't great enough to heavily shift into coking.
As I said before, the 1+ year is a good start, but several years of data will be more conclusive. But these preliminary UOAs over this last year are showing my points to be valid.
