TouringBubble
11-20-2008, 04:34 PM
I just wrote this up in reply to a question on EvoM ...
----
There are a few ways to judge intercoolers ...
Material
Size
pressure drop
end tank design
bar and plate vs Tube and fin
Row Count
Fin design
Fin density
Let's start at the top ... material. this is easy. you want a material that can dissipate a lot of heat. Aluminum is the metal of choice. Some heat exchangers are steel and they don't work as well. Steel is used when you need to cool something that is corrosive to aluminum.
Size ... the bigger the better is the common mantra. The only caveat is that larger cores generally have a larger pressure drop. More pressure drop means the turbo works harder to recover the lost pressure, so you want as little pressure drop as possible.
Pressure drop depends on many things, including core size, design and end tank design. A good manufacturer can play with these and nearly eliminate pressure drop. The stock core has a pressure drop of about 1.5psi to 2psi I think. Good aftermarket cores will be about the same.
Another note on end tanks ... a good end tank will help equalize the flow across the core and therefore increase contact with the moving air. This means better cooling as you're using more of the core's surface area for heat transfer.
The stock core is a tube and fin design and most aftermarket replacements are bar and plate. In general, bar and plate is better, although a little heavier. I'm honestly not sure why, so i can only assume that the basic design allows for more surface area and therefore more heat transfer.
the row count is simply the number of rows in the core. Many people will say that more rows is better, but that is debatable. More rows generally means more pressure drop or lower fin density. but, if you can find a core with more rows and the same fin count/design and pressure drop then it should be a better core.
Fin design and density are probably the best indication of the performance of the core. The fins are what cool the air, plain and simple. the more you have and the more contact they have with the air, the better the air will cool. A split fin design (a single row contains offset fins) is the best choice as it maintains physical area while splitting the air in to smaller channels, which allows for more air:fin contact.
----
There are a few ways to judge intercoolers ...
Material
Size
pressure drop
end tank design
bar and plate vs Tube and fin
Row Count
Fin design
Fin density
Let's start at the top ... material. this is easy. you want a material that can dissipate a lot of heat. Aluminum is the metal of choice. Some heat exchangers are steel and they don't work as well. Steel is used when you need to cool something that is corrosive to aluminum.
Size ... the bigger the better is the common mantra. The only caveat is that larger cores generally have a larger pressure drop. More pressure drop means the turbo works harder to recover the lost pressure, so you want as little pressure drop as possible.
Pressure drop depends on many things, including core size, design and end tank design. A good manufacturer can play with these and nearly eliminate pressure drop. The stock core has a pressure drop of about 1.5psi to 2psi I think. Good aftermarket cores will be about the same.
Another note on end tanks ... a good end tank will help equalize the flow across the core and therefore increase contact with the moving air. This means better cooling as you're using more of the core's surface area for heat transfer.
The stock core is a tube and fin design and most aftermarket replacements are bar and plate. In general, bar and plate is better, although a little heavier. I'm honestly not sure why, so i can only assume that the basic design allows for more surface area and therefore more heat transfer.
the row count is simply the number of rows in the core. Many people will say that more rows is better, but that is debatable. More rows generally means more pressure drop or lower fin density. but, if you can find a core with more rows and the same fin count/design and pressure drop then it should be a better core.
Fin design and density are probably the best indication of the performance of the core. The fins are what cool the air, plain and simple. the more you have and the more contact they have with the air, the better the air will cool. A split fin design (a single row contains offset fins) is the best choice as it maintains physical area while splitting the air in to smaller channels, which allows for more air:fin contact.