We have been testing heat exchangers for 10+ years now. As far as we know we are the only ones that test heat exchangers by tracking water temp in/out. Which is the ONLY way to accurately test a heat exchangers performance. There are too many very large variables in play to use intake air temperatures as a gauge of heat exchanger performance.
In one car alone, we had seven different heat exchanger configurations. Five in another. Three in two more cars. Some of them off the shelf units, some of them completely custom. We’ve tested up to 1500cu in of core volume.
After 10+ years of testing one thing rings true 95% of the time. The bigger the heat exchanger, the better it works. There is an argument that a bigger “face” will make up for lack of core volume a little though. If you have two 800cu in units your comparing but one has more “face”, go with that one.
Passes:
As far as “passes” goes we have also not seen any evidence to suggest that more passes are better. But there are situations where more passes hurts cooling because they choke down system wide water flow/speed due to the core not being large enough to run that many passes. The results are all over the place. The short version is don’t bet the farm on how many passes a heat exchanger has. It probably doesn’t matter.
Core Design:
We have yet to see any truth to a small XYZ whammie jammie heat exchanger with its NASA designed space age core with XXX better heat transfer out performing a bigger unit. It’s possible that’s a thing. We find it unlikely anyone will ever do accurate testing to determine if it’s true though. The rig you would need to build to do that sort of testing would cost a fortune. And a lot of time. There is no way to accurately measure them on a car. That said, we have a window of core specifications that have worked well for us and we stay in that window. We’re certainly not saying that the core design doesn’t matter.
Hose Size:
The hose/fitting size on a heat exchanger can make or break how much water you can flow. Almost all heat exchangers have .75” fittings. It’s very difficult if not impossible to achieve adequate water flow to control inlet air temps with fittings/ a system size that small. As a rough outline this is how much water speed changes with system-wide size change. Here are some specs based on using a Stewart E2512A water pump. Keep in mind most superchargers do not have an intercooler with bigger fittings than .625”. Some as small as .55”. So, don’t expect most systems with .75” hose to flow the .75” number below:
1.25” – 28gpm
1” – 21gpm
.75” – 13gpm
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Measuring core sizing:
This is the only way we have found to measure them consistently.
Core size, side to side (width), is measured not including tanks, just the core.
Core size, top to bottom (height) is measured from the outside (top side, bottom side) of the last “tubes” open to airflow.
Core thickness is the thickness of the core minus any headers, footers, etc.
Most advertising you see for heat exchangers contains sizing based on overall dimensions. That is not the “working size” of the heat exchanger. The core size is.
Thick/Tight Cores Are A Problem:
Through testing we have learned that once cores get thicker than 2.625” they’re too thick to efficiently pass air though them. As an extreme example we have tested a 2.65” core vs a 3.125” core. The 3.125” core had half the airflow of the 2.65”. So yes, core size/volume is very important. But only if that volume is attained without making it too thick.
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Specifications:
Department Of Boost Titanic Triple S550
Width: 22.5”
Height: 16.5”
Thickness : 2.6465”
Hose/line size: .75” – 1.25” (adjustable)
Frontal Area: 371.25 sq in
Core Volume: 982.51 cu in
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Department Of Boost Super Single
Width: 24”
Height: 12.375”
Thickness : 2.5”
Hose/line size: .75” – 1.00” (adjustable)
Frontal Area: 297 sq in
Core Volume: 742.5 cu in
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Whipple Oversize Option
Width: 22.125”
Height: 15.75”
Thickness : 3.1875”
Hose/line size: .75”
Frontal Area: 348.46 sq in
Core Volume: 1110.74 cu in
****There is a shortcoming with this HE that betrays its dimensions. It is very, very thick and has a very dense core, which makes it resistant to airflow. Thinner/taller units with a freer flowing core will shed more heat even if they have a lower core volume (not too low though). We rate our Super Single much better than this unit despite its smaller core volume. The Super Single will pass a lot more air through the core. And the Super Single can be run with up to a 1” line which is the only way to get stout water flow numbers.
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C&R Heavy Duty/Shelby Extreme
Width: 24”
Height: 12.4225”
Thickness : 1.75”
Hose/line size: .75”
Frontal Area: 298.14 sq in
Core Volume: 521.75 cu in
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Whipple 2.9L Kit Standard Unit
Width: 21.25”
Height: 15.75”
Thickness : 1.5”
Hose/line size: .75”
Frontal Area: 334.68sq in
Core Volume: 502.03 cu in
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VMP Triple (GenII)
Width: 24”
Height: 12.25”
Thickness : 1.5”
Hose/line size: 1.0”
Frontal Area: 294 sq in
Core Volume: 441 cu in
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VMP Triple (GenI)
Width: 24”
Height: 12.25”
Thickness : 1.5”
Hose/line size: .75”
Frontal Area: 294 sq in
Core Volume: 441 cu in
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LFP
Width: 21.75”
Height: 8.125”
Thickness : 2.375”
Hose/line size: .75”
Frontal Area: 176.71 sq in
Core Volume: 420 cu in
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C&R Standard/Shelby Comp
Width: 24”
Height: 9.6125”
Thickness : 1.75”
Hose/line size: .75”
Frontal Area: 230.7 sq in
Core Volume: 403.72 cu in
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Afco Pro Series (old design)
Width: 22.5”
Height: 9”
Thickness : 2” (double 1” tubes)
Hose/line size: .75”
Frontal Area: 202.50 sq in
Core Volume: 405 cu in
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Afco Pro Series w/ 10” Fans (new design)
Width: 22.5”
Height: 11.375”
Thickness : 1.25” (single 1.25” tube)
Hose/line size: .75”
Frontal Area: 255.93 sq in
Core Volume: 319.92 cu in