Everything you need to know about intercoolers… well the basics anyways

Everything you need to know about intercoolers… well the basics anyways.

Tube and Fin
Pros:
Generally weighs about half as much as a bar and plate core of similar dimensions
Generally less expensive
Generally less flow restriction within the core than bar and plate designs
Less flow restriction through the exterior allowing better flow to the rear of the core and to a radiator, AC condenser, tranny or oil cooler, etc. which may be behind it

Cons:
Those with less flow restriction than bar and plate cores offer less heat rejection
Generally have more fins which means they're more likely to be damaged by rocks/debris which cuts down on cooling efficiency
Charge air entry extends beyond core wall making it more difficult for air to enter the core cleanly

Bar and Plate
Pros:
Generally off greater heat rejection than tube and fin design
Those with turbulators offer even greater heat rejection
Offered in tons of varying shapes and sizes
Less likely to be damaged by rocks and debris
Charge air entry sits flush with core allowing for cleaner entry

Cons:
Weighs about twice as much as a similarly size tube and fin core
More expensive
Blocks more airflow to radiators, etc. which may be behind it
Those with turbulators have greater flow resistance to charge air

Remember that there's a balancing act between cooling and airflow restriction within the core. The more densely packed turbulators are within a bar and plate core the more cooling will be done as the air passes through, but the greater flow is restricted.

There are many crappy cores for sale on ebay and they are now becoming a common item at so called performance shops. In the product images they show the cores and you can see right down them because there are no turbulators present. Without these all you have is big chunk of metal with poor cooling. People are always saying the ebay ICs flow great. Sure they do, straight pipes with no restrictions do flow nicely.

In terms of the core itself, some bar and plate cores use radiused ends (not end tanks) to promote flow. I made a quick drawing to illustrate this. You can see how the airflow will enter the core more readily when the ends are radiused rather than flat. Air is less likely to collide and swirl, and more likely to curve in.

And here are some pics which illustrate what I meant when I said the charge air entries on a bar and plate sit flush with the core...and the tube and fin entries protrude:

And lastly some radiused end tanks which promote uniform flow:

Fin Packing: Here we talk about the fin packing, internal and external design. For the intercoolers that use a fine internal fin packing there are two configurations. There is the standard packing and there is the staggered fin packing. In the standard fin packing all of the fins are in-line. If you look down the tube of this design you will usually see light through the other end. In the staggered fin packing the fins are staggered so more of the air comes into contact with the fins. If you look down the tube in this design you will rarely see any light from the other end. This design is superior because it is more efficient from the air coming into contact with more fins, but will slightly hinder flow but not significantly unless it very densely packed. There are some companies that use a very dense fin packing which is one of the most efficient on the market, but also flows the least because of it. The same applies for the external fin packing between each tube. The external fin packing is usually heavier since they are exposed to oncoming objects such as rocks and debris found on the road.

Fin Design: Another factor that affects efficiency is the fin design. Fins are commonly just thin, flat pieces of aluminum. In some cases these fins are "louvered", similar to what a cheese grater would look like. These little louvers help catch the air and direct it through the fin and improve efficiency allowing the air to contact more of the fins surface area instead of just the leading edge of the fin.

Standard Fin Packing	Staggered Fin Packing

Core Configuration: There are two configurations for air to air intercoolers. Cross flow and Vertical Flow. In the pictures below, the tubes are shown in light gray with the fin packing between each tube. The cross flow are the better design because of the efficiency of the longer core. Because of the longer core the air stays in the core longer allowing it to draw more heat out of the air charge. Since the cross flow is shorter in height (ie less amount of tubes) it does not flow as much as a Vertical flow core. The vertical flow core, since it has more tubes it flows significantly more air, but because the core is shorter in length, the air doesn't stay in the core long enough to draw a lot of heat out of the air charge. Vertical flow cores work well with very high horsepower applications and are usually recommended for supercharged applications.

Crossflow Core (7 Long Tubes)	Vertical Flow Core (19 Short Tubes)

Internal Airflow: As airflow travels through an intercooler it chooses the shortest path through the core. In the diagram below it shows a core with 7 tubes, lets say each tube flows 100cfm for a total of 700cfm. If you are only flowing 300 cfm through the core you are really only using 3 of the tubes, the ones directly between the inlet and outlet. As flow increases, it will begin using the upper tubes. This will also help when mounting the intercooler. If the bottom rows were covered by the bumper and the upper tubes were exposed you would not be receiving the maximum performance possible from the intercooler.

Internal Airflow @ 300cfm

Intercooler piping and Clamps.

For 3PLY (thick) coupler typically you would need 1/4" larger Tbolt clamp for the size of pipe you need, for example if you have a 2.0" ID silicone coupler you will need to purchase a 2.25" tbolt clamp in order to compensate for the extra silicone.

For 4PLY (thick) coupler typically you would need 3/8" larger Tbolt clamp for the size of pipe you need, for example if you have a 2.0" ID silicone coupler you will need to purchase a 2.38" tbolt clamp in order to compensate for the extra silicone.