OILED vs DRY FILTERS w/ PLOT TWIST: IAT

[WildHorse]

but on a MAF car, I run dry, my other cars are MAF, so I run dry filters. isn't worth risking the sensor from too much oil

Well if one follows the instructions for re oiling, it's not a problem.

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[FreePenguin]

Well if one follows the instructions for re oiling, it's not a problem.

still a worry, I do follow instructions, but im a worry wort.

 

[AZ18yote]

I realize not conical but stock box with K&N oiled drop in vs AFE dry drop in I noticed a slight increase of avg iats on the AFE. When I say slight I mean like 3-5 on avg. I had assumed it was due to material differences but it may very well have been oiled vs dry.

 

[Dave2013M3]

To be honest I don't think whether its oiled or dry will affect IATs. I for one believe the elevated IATs from the CAI is from the thin plastic that a lot of these CAIs use including the Ford Racing. That sucker is right in front of the driver side exhaust manifold and that plastic gets heated. The OEM box is a very thick plastic and insulates the intake better. I am going to try a self adhesive heat wrap on the rear of my CAI to shield it from the header.

 

[GregO]

The OEM box is a very thick plastic and insulates the intake better.

Something that never gets mentioned is the design of the OEM lower box and what appears to most as internal reinforcement plastic molded gussets.
The labyrinth of raised gussets isn’t just for strength, they serve a bigger purpose.
1- They assist to break the surface tension of the incoming air and help it turn from horizontal flow to vertical flow.
2- The dead space between each gusset provides a thermal break. This is very similar to the same principle of dual pane windows or anything where insulating values are of importance.

 

[WildHorse]

To be honest I don't think whether its oiled or dry will affect IATs.

See pic in post #10. 1 degree difference in IAT vs Ambient. Repeatable.

 

[Dave2013M3]

See pic in post #10. 1 degree difference in IAT vs Ambient. Repeatable.

To be honest bro at that difference if I already had a dry filter I wouldn't sweat it. I have an oiled Air Raid filter in my Ford Performance intake.

 

[WildHorse]

To be honest bro at that difference if I already had a dry filter I wouldn't sweat it. I have an oiled Air Raid filter in my Ford Performance intake.

Not sweating. I just find it interesting that a medium like filter oil can have such an effect.

https://en.wikipedia.org/wiki/Oil_cooling#:~:text=Oil cooling is the use,known as an oil cooler.

 

[markmurfie]

ugh... This is not how heat works. The filter is not cooling the air charge, Its the opposite.

Sitting in your engine bay, your intake air filter is at a higher temperature than the incoming air just arriving into your engine bay. Heat moves from higher temperature to lower temperature, its just a matter of how fast. Things like the objects relative states and surface area have an effect on the heat transfer rate. This means the filter is always soaking up heat from the engine bay and increasing the temperature of the air, its just a matter of how much. A liquid like oil would increase this heat transfer rate. At a some point the incoming air charge will be great enough pulling heat away from the filter and the filter will cool enough where its temperature differential will be minimal from incoming air and its effect on the air charge temperature will also be minimal.

 

[WildHorse]

ugh... This is not how heat works.

Thermal conductivity for common materials and products @ 25c :

light oil 0.15
cotton 0.23
Water 0.606

So the oil acts like an insulating layer, preventing excessive heat build up, and accelerates cooling.

 

[markmurfie]

Cotton is much lower than oil, more like 0.023 W/m*K. Its really good at not allowing heat transfer and why it makes good clothing or insulation, as long as it is dry. Once wet/oiled it is not a good insulator. Heat will transfer to it quicker, but also away from it quicker.

 

[Dave2013M3]

Not sweating. I just find it interesting that a medium like filter oil can have such an effect.

https://en.wikipedia.org/wiki/Oil_cooling#:~:text=Oil cooling is the use,known as an oil cooler.

That is interesting..I have been using this oiled JLT in my FR intake.

 

[Red65]

I keep mine dry, but I also run a thin outer cover. I believe oiling is necessary in HIGH dust environments, but not needed on the average street car.

Uhhh... If the filter is designed to be oiled, it's not just a recommendation for dirty/dusty areas. It NEEDS the oil to filter properly. Dry filters filter the air via a paper medium that has tiny tiny tiny microscopic holes that are small enough to let air through but are able to stop airborne particles to the point that the auto industry can guarantee the safe operation of the engine. Cotton-woven oiled filters have MUCH larger openings (in the microscopic sense) in the cotton weave which allows more air in but when filter oil is applied to the weave, it gives it a tackiness that allows it to "wick" dirt out of the air and hold onto it as the air passes through. Without the oil, a supposed-to-be oiled filter is just a really, really bad dry filter.

 

[FreePenguin]

Uhhh... If the filter is designed to be oiled, it's not just a recommendation for dirty/dusty areas. It NEEDS the oil to filter properly. Dry filters filter the air via a paper medium that has tiny tiny tiny microscopic holes that are small enough to let air through but are able to stop airborne particles to the point that the auto industry can guarantee the safe operation of the engine. Cotton-woven oiled filters have MUCH larger openings (in the microscopic sense) in the cotton weave which allows more air in but when filter oil is applied to the weave, it gives it a tackiness that allows it to "wick" dirt out of the air and hold onto it as the air passes through. Without the oil, a supposed-to-be oiled filter is just a really, really bad dry filter.

have to agree on this, that's why afe filters are 3 thicker more dense filters for dry, and 5 thinner filters for wet.

 

[Schwerin]

I keep mine dry, but I also run a thin outer cover. I believe oiling is necessary in HIGH dust environments, but not needed on the average street car.

You may wanna take of you intake tube and see how dirty it is inside.

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