Thermal Fans Running For Short Time After Engine S

[THEMESHMAN260]

Has any one notice in their BFII that they only have one thermal fan now the BA and MKI and II and XR8 HAVE 2 not the early BFII but the ones now and have you noticed any different in cooling

[Iconic Bionic]

Has any one notice in their BFII that they only have one thermal fan now  the BA  and  MKI and II and XR8 HAVE 2  not the early BFII but the ones now and have you noticed any different in cooling

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Yeah me BFI has 2 fans.

[Iconic Bionic]

...or thermosyphon

I believe the process is called convection.

The heat from the turbo heats the surrounding coolant causing it to expand which forces it through the system. This process will slow and eventually stop as the turbo cools.

I believe the use of a turbo timer isn't solely for cooling.

If you shut an engine down straight away after a hard blast the turbo is still spinning at incredible speeds but there is no oil flow or pressure to keep the turbo properly lubricated and the turbine shaft floated so damage can quickly occur. If you leave the engine running you are cooling the turbo but you are also slowing the turbo down while still providing oil to lubricate it.

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Wow. What an answer. Thanks.

[tab]

...or thermosyphon

I believe the process is called convection.

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That's something that happens in your oven

[Kimberley Scott]

If I can remeber my Year 10 science properly

Convection is the transfer of heat from a solid to a gas, ie turbo to air.

Conduction is the transfer of heat from a solid to another solid or a liquid, ie Turbo to oil.

There are at least a couple more ways of heat transfer, but for the life of me the names escape me.

Scotty

[Kimberley Scott]

If I can remeber my Year 10 science properly

Convection is the transfer of heat from a solid to a gas, ie turbo to air.

Conduction is the transfer of heat from a solid to another solid or a  liquid, ie Turbo to oil.

There are at least a couple more ways of heat transfer, but for the life of me the names escape me.

Scotty

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Nope my memeory stinks

So here is the DS answer

Heat transfer mechanisms can be grouped into 3 broad categories:

Conduction: Regions with greater molecular kinetic energy will pass their thermal energy to regions with less molecular energy through direct molecular collisions, a process known as conduction. In metals, a significant portion of the transported thermal energy is also carried by conduction-band electrons.

Convection: When heat conducts into a static fluid it leads to a local volumetric expansion. As a result of gravity-induced pressure gradients, the expanded fluid parcel becomes buoyant and displaces, thereby transporting heat by fluid motion (I.e. convection) in addition to conduction. Such heat-induced fluid motion in initially static fluids is known as free convection.

For cases where the fluid is already in motion, heat conducted into the fluid will be transported away chiefly by fluid convection. These cases, known as forced convection, require a pressure gradient to drive the fluid motion, as opposed to a gravity gradient to induce motion through buoyancy.

Radiation: All materials radiate thermal energy in amounts determined by their temperature, where the energy is carried by photons of light in the infrared and visible portions of the electromagnetic spectrum. When temperatures are uniform, the radiative flux between objects is in equilibrium and no net thermal energy is exchanged. The balance is upset when temperatures are not uniform, and thermal energy is transported from surfaces of higher to surfaces of lower temperature.

This was taken from this webpage

http://www.efunda.com/formulae/heat_transfer/home/overview.cfm

Scotty

Edited 04/12/06 07:35 AM by Kimberley Scott

[Adam]

The three methods of heat transfer are conduction, convection and radiation.

Convection is the movement of currents within fluids. It cannot occur in solids due to the particles not being able to flow freely.

[Kimberley Scott]

Correct.

Scotty

[XR68UZ]

good stuff guys. a pat on the back for all you you's.

now back to the original question, can this be done? the vw have this feature as well. sometimes when I turn on the car, the cooling fan comes on after a few seconds.

[Evil F6]

good stuff guys. a pat on the back for all you you's.

now back to the original question, can this be done? the vw have this feature as well. sometimes when I turn on the car, the cooling fan comes on after a few seconds.

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Heck even my VT LS1 had this feature.