Headers and the blower housing outlets Options

[rfinegan]

I have headers on my 2056 and no heat. What are people doing wit the outlets on the Fan/Blower housing at the bottom of the engine?

1) Leave them open and let them blow. NO HE or Tubes and such any more

2) Close off the blower outlets on the housing?

NOTE: this is not the aux electric blower that turns on with the heater in the engine bay


this was an older topic but I’m not finding with me search criteria

[rfinegan]

I have an old housing, it would be fun to reshape the inside to delete the outputs, but I would not have any way to measure the results? and NOT pulling it at this time to play
One would guess that it will make more flow if done correctly?


IF its better flow and better cooling? Is more flow/ faster flow better cooling?

Some one must have done this before this thread?

[Superhawk996]

Is more flow/ faster flow better cooling?

Rarely.

The problem is that airflow isn’t the dominant factor - it’s the extremely limited ability of air to cool vs a liquid like water. The dominant factor in air cooling is the temperature differential between the ambient air and the engine.

Here’s a chart of the heat transfer coefficient of air (Hc) vs air velocity



You’ll notice it (Hc) gets flatter as air velocity increases. You can do the thought experiment that if you were able to achieve a sky high velocity; the cooling would diminish because the cooling air would be moving so fast, it wouldn’t even have time to pick up heat from the head because of the short time the air is exposed to the head, and the poor thermal conductivity of the air itself.

So unless you’re starting low on the curve with very slow airflow, the gains diminish as velocity increases due in part to the compressibility of air. Meaning it’s taking a bigger and bigger fan to increase air velocity with more HP being required to drive the bigger fan.

I don’t have the airflow velocity numbers for the T4 engine (could be measured) but I’d be willing to bet that Porsche engineers optimized the airflow vs HP consumption. As a result, trying to move the operating point by increasing air velocity will only net you diminishing returns.