My newly ceramic coated engine bay parts
05-03-05, 12:00 PM
#26
Originally Posted by zullo
Unfortunately I think the point Max was trying to emphasize was missed.
The temperature of your motor will not change or could technically go up since you are not transferring heat out of or through those parts as efficiently as you were before. Note the difference is academic only since 99+% of the cooling is via radiator and oil coolers...
The temperature of your motor will not change or could technically go up since you are not transferring heat out of or through those parts as efficiently as you were before. Note the difference is academic only since 99+% of the cooling is via radiator and oil coolers...
Its cooler air on the inside so it helps to keep this charge cool. If the UIM was on the hot side (eg downpipe) then yes it would hold heat in instead of allowing it to escape into the bay. Ceramic acts as a barrier, either as holding heat in or stopping heat from absorbing/penatrating.
05-04-05, 11:04 AM
#28
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Like Max said, it is unclear if the major source of heat introduced into the UIM is coming from the surrounding air or from the physical connection the the engine. Metal to metal contact is a wonderful heat transfer medium. It just might be the case where the surrounding air is cooling the UIM. If this is the case, the external coating could do more harm than good, although the internal coating would reduce the heat transfer rate to the intake charge. The benefits of ceramic coatings are clearer (at least to me) on parts such as the downpipe.
05-04-05, 11:03 PM
#30
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Originally Posted by maxcooper
Thermal barrier coatings are easy to understand. They don't like for heat to pass through them -- they slow the rate at which heat can move from one side of the coating (say, a manifold) to the other side of the coating (say, the air that surrounds the manifold). Apply that simple rule to any situation in which you may be considering their effects and that should help you figure out what happens. The harder part is figuring out the rate at which heat really flows through the boundary (the manifold / surrounding air boundary, for instance) that you are considering coating, and sometimes which side is really hotter. Heat flows -- the point of coatings and other thermal management techniques is to reduce the amount of heat that will flow from the hot stuff into the stuff you want to keep cool (or the other way around). Always think about flow when you are doing thermal management stuff -- where does heat come from, and what do you want to keep it in or out of?
With the UIM, consider that the heat of the air surrounding the UIM might be hotter than the UIM. And the cool air flow through it is pulling heat out of the UIM from the inside and taking it into the engine. And that is really the goal -- to reduce the intake temps. Keeping the manifold cool for the sake of keeping the manifold cool is pointless -- who cares what temp the manifold is? If you coat the UIM, less heat will flow from the air outside the UIM into the UIM, and then into the air that is flowing through the UIM. You reduce the amount of heat that flows from one place to another.
I had my LIM and UIM coated, too. However, I think two things make it not all that effective. One is that there just isn't a whole lot of heat flowing from the UIM into the air that is quickly rushing though it. So, even if you reduce it by half, the effect isn't very significant. The other issue is that I do think a fair amount of heat flows from the engine block to the LIM and then into the UIM, all through the gasket mating areas. It might even be that more heat flows into the manifolds this way than they absorb from the air that surounds them. The thermal barrier coating traps some heat in the manifolds if that is really the case. Note that "traps in" just means "releases at a slower rate" -- I don't mean that it literally locks the heat up in the manifold, never to escape -- remember, the coatings simply slow the rate at which heat can pass through the surface that you coated. I don't know that more heat comes from the gasket mating areas (and it might be that there isn't one answer to the question -- it could be "sometimes yes, sometimes no"), but it is food for thought.
-Max
With the UIM, consider that the heat of the air surrounding the UIM might be hotter than the UIM. And the cool air flow through it is pulling heat out of the UIM from the inside and taking it into the engine. And that is really the goal -- to reduce the intake temps. Keeping the manifold cool for the sake of keeping the manifold cool is pointless -- who cares what temp the manifold is? If you coat the UIM, less heat will flow from the air outside the UIM into the UIM, and then into the air that is flowing through the UIM. You reduce the amount of heat that flows from one place to another.
I had my LIM and UIM coated, too. However, I think two things make it not all that effective. One is that there just isn't a whole lot of heat flowing from the UIM into the air that is quickly rushing though it. So, even if you reduce it by half, the effect isn't very significant. The other issue is that I do think a fair amount of heat flows from the engine block to the LIM and then into the UIM, all through the gasket mating areas. It might even be that more heat flows into the manifolds this way than they absorb from the air that surounds them. The thermal barrier coating traps some heat in the manifolds if that is really the case. Note that "traps in" just means "releases at a slower rate" -- I don't mean that it literally locks the heat up in the manifold, never to escape -- remember, the coatings simply slow the rate at which heat can pass through the surface that you coated. I don't know that more heat comes from the gasket mating areas (and it might be that there isn't one answer to the question -- it could be "sometimes yes, sometimes no"), but it is food for thought.
-Max
Keeping the UIM cooler could be handy because the air intake temp sensor is in there and heat tranferring to the sensor (heatsoak) causes us to tune richer to prevent lean conditions. Have you noticed heatsoak takes longer or is less severe with your manifolds ceramic coated?
Here is my take on the advantages of ceremic coating the UIM...
1. Reduces intake temperatures. Small gain here at best as you point out.
2. Reduces heat soak at air temp sensor. I think it would be significant but I'm asking for your real world input
. Some would say relocate the sensor but it's some trouble and having the sensor closer to the combustion chamber is more accurate.3. Smooths the flow of air. The inside of the UIM are quite ruff and hard to reach to smooth out so adding a coating to the inside should improve power.
4. Looks better. Beauty is in the eye of the beholder
.Several small advantages added together make it start to look appealing.
05-05-05, 02:02 AM
#31
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i believe what Max and Zullo was trying to say is that, since these parts are coated, less heat or slower the heat will travel into these peices, causing the outside (engine bay) surrounding air to be hotter. Therefore creating more heat that will damage hoses, lines, etc.
05-05-05, 05:53 PM
#33
Originally Posted by c h I n e Z e~BoY
i believe what Max and Zullo was trying to say is that, since these parts are coated, less heat or slower the heat will travel into these peices, causing the outside (engine bay) surrounding air to be hotter. Therefore creating more heat that will damage hoses, lines, etc.
05-05-05, 06:05 PM
#34
Lets make this easy.....
The colder the charge entering the UIM the better, if it can be done in anyway.
First of all the uim does not produce heat, its cold from the start. there are only two ways for the UIM to get hot. Engine bay heat (absorbtion) and heat from contact with the LIM (absorbtion) wich gets hot from contact from the block.
The coating stops engine bay heat from absorbing into the metal of the UIM helping to keep the charge cooler. Ok step one done, but what about contact/absorbtion with the LIM metal?
This is why the UIM is coated on the inside also. Any heat trying to get through the UIM into the chambers of the intake is now stoped again by the inner coating. Up to 2000 degrees this will hold heat back so the charge will stay cooler.
The colder the charge entering the UIM the better, if it can be done in anyway.
First of all the uim does not produce heat, its cold from the start. there are only two ways for the UIM to get hot. Engine bay heat (absorbtion) and heat from contact with the LIM (absorbtion) wich gets hot from contact from the block.
The coating stops engine bay heat from absorbing into the metal of the UIM helping to keep the charge cooler. Ok step one done, but what about contact/absorbtion with the LIM metal?
This is why the UIM is coated on the inside also. Any heat trying to get through the UIM into the chambers of the intake is now stoped again by the inner coating. Up to 2000 degrees this will hold heat back so the charge will stay cooler.
05-05-05, 07:48 PM
#35
What I was trying to say is that it isn't clear which of these two possibilities is true:
1. The air surrounding the UIM is hotter than the UIM. In this case, coating the UIM should make your intake temps cooler (though it is very likely to be a small effect).
2. Oh crap -- the UIM is actually hotter than the air that surrounds it! I guess the heat transfer from the engine to the LIM and then to the UIM actually makes the UIM a heat source. In this case, the intake temps will be slightly higher than they would be without the coating (though it is very likely to be a small effect).
-Max
1. The air surrounding the UIM is hotter than the UIM. In this case, coating the UIM should make your intake temps cooler (though it is very likely to be a small effect).
2. Oh crap -- the UIM is actually hotter than the air that surrounds it! I guess the heat transfer from the engine to the LIM and then to the UIM actually makes the UIM a heat source. In this case, the intake temps will be slightly higher than they would be without the coating (though it is very likely to be a small effect).
-Max
05-05-05, 08:52 PM
#38
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For what it's worth, I really like the look, and I really like the fact that you are doing something different from the usual polished look. Fantastic.
The issue of heat transfer is really moot, as any difference will be pretty negligible from coating those pieces, but it does make for an interesting discussion imho...
The issue of heat transfer is really moot, as any difference will be pretty negligible from coating those pieces, but it does make for an interesting discussion imho...
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