Process West Top Mount Intercooler WRX

The goal when developing our new top mounted intercooler was to make it the very best aftermarket top mounted intercooler for WRX/STi… period. We studied our competitors products and fixed all of the mistakes they have made…some of them major.

The most obvious error that EVERY one of our competitors makes is not supplying their intercooler with proper ducting/shrouding to suit the increased size of the new intercooler. There is no point in installing a larger intercooler and leaving the factory under bonnet splitter/shroud in place. Here is the solution. A properly sized splitter/shroud to suit the application.

The next major problem that we see competitors doing (and they all copy each other) is building an intercooler that is too thick. Their design criteria is spot on for bragging rights whilst marketing. They say that bigger is better. This is totally not the case with an intercooler that is mounted at 90 degrees to the ambient air flow. For good heat exchange to take place you need good ambient airflow through the intercooler. In the case of the boxer engine with its intercooler mounted under a bonnet scoop the ambient airflow speed is already struggling after doing a 90 degree turn through the scoop. The last thing it now needs to do is find its way through 4.5in of intercooler core. This will result poor heat exchange and high inlet temps. Our intercooler is 3.5in thick and in turn the intercooler breathes, gives lower outlets temps and in turn more power.

Turbo compressor outlet to intercooler (Y-pipe) design

Almost all of the aftermarket Y-pipes we see do not distribute the charge air flow along the intercooler evenly. It’s easy to see that our Y-pipe will give perfect charge air distribution.

Dyno Testing

Before looking at the results below, we must say that dynos and top mounted intercoolers are not a great mix- no matter where you position the dyno fan there is still very little air flow into the bonnet scoop. Having said that both the stock intercooler and the PW upgrade intercooler were subject to exactly the same test conditions. A few other things worth mentioning. The test vehicle was a stock (apart from a BPM GT exhaust system) 05 WRX. Stock WRXs consistently put down about 90kw ATW on this dyno. The intercooler outlet temp probe was placed in the silicon hose joiner at the throttle body. We started off with the PW intercooler/splitter and did a base line power run. Result was 115.5kw. Looking at the intercooler outlet temp saw a peak of 51 deg C. We must say at this point we were a little disappointed. We saved all of the data collected during the run so that we could overlay it with the results from the stock intercooler. Next we installed the stock intercooler/splitter. Max power was 107.5kw. More disturbing was how badly the factory WRX intercooler performs.

Verticooler (08-14 WRX, 15+ WRX)

Verti-Cooler combines the advantages of a large and free-flowing Process West core (400mm flow length, 205mm stack height, 120mm thick) with a design that mounts the new intercooler at a 15 degree, near vertical angle in the engine bay. Packaged with a new hood duct design that force-feeds external airflow straight onto the intercooler fins, there is now a highly efficient air exit path courtesy of the Verti-Cooler mounting angle that flows all of this (now heated) air back down through the engine bay and out the underside of the car through the transmission tunnel for a shallow, cool, and low restriction exit-path. Compare then the near on 90 degree angle that the air must turn with the stock intercooler setup in place, and the advantages of the Process West Verti-Cooler design become clear. Verti-cooler also has the largest volume of any aftermarket intercooler for the Subaru WRX 08-21, with core measurements of 400mm flow length x 205mm stack height x 120mm thick.

Khanacooler (15+ WRX)

Our new and highly anticipated ‘straight-fit’ Intercooler, the Processwest ‘KHANACOOLER’ is here now. Taking the technology used in our world-leading VERTICOOLER system and integrating it into a conventional Top-Mount setup for ease of fitment and factory-style appearance, KHANACOOLER represents a fantastic first step into the world of Subaru modification.

• High Flow Process West Bar and plate core measuring 347 x 225 x 100
• Compatible with factory charge pipe or can you add the Process West charge pipe
• Comes complete with under hood duct and engine pulley garnish

The good news is that for those of you that value a clean looking engine bay the Processwest KHANACOOLER works with the factory duct which means you don’t need to add any unsightly parts to the engine bay to have the whole system working clean and cool.

Top Mount Intercooler (22+ VB WRX)

When you are upgrading to a larger turbo or driving the car hard it is important to keep the air charge as cool as possible. Even though the stock intercooler is able to flow sufficient air, it is still only designed for mild driving and stock power levels.

When pushing the car hard, the stock intercooler will heat soak quickly and take a long time to cool back down. This causes the performance of the motor to decline and power to suffer. The Process West intercooler is a direct factory replacement that features a larger than stock core and lower pressure drop. These 2 features previously stated allow the intercooler to flow more air while reducing the amount of pressure that is lost over the surface of the intercooler. These features allow the intercooler to work better for longer and also allow a larger amount of air to pass through the core. The combination of these things will allow this intercooler to handle upwards of 400WHP. This Process West TMIC includes everything needed to make it a direct factory replacement.