The ETS Intercooler is a 4th generation design, which has been refined year after year to better suit the performance requirements in the street/strip racing industry. As the majority of our intercooler kits are used on dual purpose vehicles, we needed a core that was at home on both the street and the track. In the beginning, when prioritizing the balance between street and track, we felt that because 99% of the time, our customers are driving on the street, that our 1st design should be geared towards street use. Our priorities for street use are as follows:
Good Airflow to the Rad.
High Efficiency
Low Back Pressure
Durability
Lightweight
Good Looks
Availability
To satisfy these conditions, our first cores were tube and fin which, with their round nosed edges, offered great airflow to the radiator. We considered 3 main manufacturers in our first designs. These were Griffin, Modine, CG&J, US Fabrec, Garrett T&F, Garrett B&P. All of these units had their pros and cons, we will list some features for each manufacturer, below.
In our opinion:
Griffin: Good Airflow to the Radiator, Low Back pressure, Lightweight, Good Looks. This core was tested in various application, we found it only useful for the Mazdaspeed Protégé Side mount, as that IC was so small, that we needed low back pressure at almost all costs. Because of the SMIC location, the lack of durability was not an issue. It worked well until availability became a major issue.
Modine: Good Airflow to Radiator, Durable, High Efficiency, Lightweight, Good Looks, Available. As this was the only unit that satisfied 5 out of 6 areas of our criteria, we conducted a series of tests, using 3 shop vehicle that we had. (1000hp-v8-300zx, t66 rx7, 16G DSM ) This core performed very well on all of these vehicles, and had the best all around performance. We chose this core for many of our early intercoolers.
CG&J: Good Airflow to Rad, Good Efficiency, Low back pressure. These cores worked as good as the modine, but the only part that was better was a slightly lower back pressure ( 10% less ). We did not use these core because they were not as durable and they were not beautiful enough for front mount applications. (due to a nocolock brazing, instead of vacume brazing)
US Fabrec: These were extruded tube cores, with minimal internal fins. This resulted in little back pressure, good air to the rad, lightweight, good looks, but relatively bad efficiency. For the lack of efficiency, these cores were not used.
Garrett T&F: These are basically the same cores as Garrett uses in OEM applications. They performed exactly the same as the CGJ - Good Airflow to Rad, Good Efficiency, Low back pressure. These cores worked as good as the modine, but the only part that was better was a slightly lower back pressure ( 10% less ). We did not use these core because they were not as durable and they were not beautiful enough for front mount applications. (due to a nocoloc brazing, instead of vacuum brazing)
Garrett B&P: The garrett bar and plate units were tested, but caused overheating in the Rx7 and the DSM, as they did not get enough air to the Radiator. Even though they performed very well in the efficiency and back pressure tests, we felt that if the engine couldn't stay cool, that you car would not be on the road too long. For this reason we only used this core for special requests.
With our testing finished, we decided that the modine was the core of choice, we made a special deal with the west coast modine warehouse, and we had them manufacture the cores for us in the sizes we needed. These cores enjoyed much success, and we used them for some time, selling over 4000 units. The only shortcoming of these cores, was the higher back pressure, and availability in thick sizes was becoming an issue. For these two reasons it was becoming hard for us to satisfy the intercooler requirements of high horsepower vehicles. ( 700+ hp ). Then as modine started shutting down domestic manufacturing plants, and going through a corporate restructuring, we were told that we would not be able to get the cores we wanted. Luckily, as we were now buying cores by the ton (yes the ton), we had the purchasing power to deal with other direct manufacturers.
ETS Bar and Plate Cores
As we were losing availability of our modine cores, we were also testing new bar and plate cores, built to our specifications, buy a contract manufacturing companies in Mexico and Brazil. We were considering using a B&P core, as for any given width, the bar and plate cores had an average of a 10% larger internal flow area, and the only place that our modine units were lacking was in flow. The 10% larger internal area, was a free 10% increase in flow, and it was a 10% increase in heat transfer area ( explained later ). The only place that the Bar and Plates units were insufficient was in allowing good airflow to the radiator, which we would attempt to rectify. With these new suppliers, we were able to spec the cores we needed, and we were able to test various different fin combinations, as well as different overall construction designs. Some examples of tested cores are:
T&F- louvered internal, louvered external fins
T&F- offset internal, offset external fins
T&F- offset internal, louvered external fins
T&F- louvered internal, offset external fins
B&P- louvered internal, louvered external fins
B&P- offset internal, offset external fins
B&P- offset internal, louvered external fins
B&P- louvered internal, offset external fins
Did not test extruded tube core - we know they are bad
Did not test any cores with straight through fins- also bad
What we finally settled on was a bar and plate core, with offset and staggered internal fins, and louvered external fins, with the external fins being 30% larger that the internal fins. By having the external fins larger than the internal fins, it allowed us to decrease the external fin density, so that they would allow adequate air to the radiator. This combination allowed us to have the most efficient core possible, and it would not overheat even the sensitive vehicles ( Rx7 & 300zx ).
To fully understand the ETS perspective on intercooling; please clicks here. Below are some highlights of our cores.
Louvered External fins allow ample air to the radiator, while still retaining acceptable efficiency levels. The big issue with the external fin pack was to either use a very dense fins pack, or a looser fin pack, and then to use an offset fin pack, a straight fin pack, or a variant. We started with a dense, offset external fin pack as we knew that this would be the most efficient. These intercoolers had very good low-speed efficiency as well as good high speed efficiencies. But they did block a lot of air to the radiator, and the A/C condenser. We observed warmer coolant temps with this core, causing the fans to come on more often on the freeway. The big problem area was going up long hills at part throttle, and the fact that the vehicle could not take sustained in-boost driving, as the coolant temps would rise. Our conclusion was that the high density, offset external fins had great efficiency, but just blocked too much air to the radiator for a good street/strip core.
Our next step was to loosen the external fin counts. So we increased the fin spacing of the external fins. As we increased the fin spacing, we noticed that the only place we really lost efficiency was at low speeds. At speeds above 35mph, the efficiency was virtually the same as the high density fins, that were blocking so much air to the radiator. We finally go to a fin spacing that did not overheat the test vehicle. In this scenario the fins were so far apart that we felt that we may be able get the same results with a straight, but louvered external fin. The reason that we wanted to try the louvered external fin, was that our widely spaced, but offset external fins just looked really funny. Our first test with the louvered external fins was successful, and after a few more tests, we had an external fin that was as dense as possible, without overheating the vehicle. These fins worked very well, only giving up efficiency below 35mph. Since most vehicles, when under boost are above 35mph, this was not an issue.
Offset & Staggered Internal Fins. At this point in the testing, we were using the louvered internal fins, just like in the modine cores we had used in the past. These fins were very efficient, but were a little too restrictive on flow, when we couldn't size the intercooler for the application. Also at this time, our average customer was now making 400-600hp, not 300-400hp as when we first started. To satisfy the higher average power levels that people were achieving, we switched the internal fins from an louvered and staggered, to an offset and staggered arrangement. The offset fins are unique in that they flow well, and retain a high thermal efficiency. These fin split the air 1000's of times as it travels through the core. As it splits the air so many times, we feel it allows more air molecules to contact the internal fins, so they can transfer the heat to the external fins. This differs from the louvered fins, which induce turbulence, that is, they make the air roll, like a tumble weed.. We feel that splitting the air gets more molecules in contact with the internal fins than rolling the air through like the louvered fins do By utilizing the offset internal fins it allowed all of the cores to flow better, and maintain a high efficiency rating. We also tried increasing the height of the charge air passages; this did help internal flow, but hurt thermal efficiency, and hindered flow to the radiator. These offset and staggered internal fins are the heart of our intercoolers, and this specialty fin pack is what give our intercoolers their high efficiencies.
More Charge Rows increase heat transfer area As stated above, we did try larger charge air passages, as this is a characteristic of other well known cores in the industry. We found that when we increased the height of the charge air channels, the flow went up, but the efficiency went down. The drop in efficiency was directly related to the lack reduction of the total heat transfer area of the core, and the internal, to external fin density was no longer in balance.
Vacuum Brazed All current ETS cores are of a Bar and Plate, vacuum brazed construction. This means that they are brazed in an oxygen free environment which yields very strong joints, and a good looking, bright finish.
Heat Treated External Fins The external fins are heat treated to allow the core to stand up to bugs and small rock debris. The brazing process does take out some of this heat treat, but our external fins are some of the strongest in the industry, and will stay straight, longer.
Because of the features stated above, and the fact that our cores are the product of real-world testing, we feel we have the best core on the market today. Our cores have been used on Street, and race machine across the world. They have also enjoyed success in the air and on water, with never an unhappy customer. Our intercoolers are a product of the intercooling philosophies which we believe in, here at ETS, and successful results in the hands of our customers prove this performance time and time again.
ETS Intercooling Applications of Note:
Ray 7.8sec mustang, ETS Water to Air - 69deg charge air temps at 1500+ hp 20psi
Rrev 8.15sec Supra, ETS 6" Air to Air- 130deg Charge Air at 1150+ whp 46psi (8.28sec Video)
Paul 9.43sec Mitsubishi Evo ETS 5" Air to Air - 120deg Charge Air at 1014 whp 53psi
Lucas 10.8 sec Daily Driven Eagle Talon, ETS Race Kit- 118edg Charge Air at ??? whp, 30psi
