Muscle Mustangs & Fast Fords
Installing Air-To-Water Intercooler - Arctic Boost
Drop Inlet Air Temps On Your Blower Or Turbo-Equipped S197 With JPC's Air-To-Water Intercooler.
"Cold air is more dense and carries more oxygen molecules," was the response Justin Burcham of JPC Racing blurted out when we asked about his reasoning for adding the new JPC Racing air-to-water intercooler to many of his high-horsepower, forced-induction customer cars. The modification is a simple solution to an increasing problem that Burcham realized while racing his popular '05 Mustang GT in MM&FF/NMRA True Street competition.
The True Street Challenge is a torture test for an 8-second ride like the one he brings to battle. The 30-mile cruise heat-soaks the engine, supercharger, and transmission before competitors attempt to perform three consecutive runs down the track-without the aid of cooling the car or popping the hood. Factor in the sweltering summer temperatures and you can see why heat from a supercharger can be a problem for all-out performance.
Burcham continually saw his inlet air temperatures climb high as the air-to-air intercooler attempted to bring it down to reasonable levels. "I have seen temps as high as 300 degrees on my car and many big-boost turbo and supercharged customer cars. The intercooler would barely do anything because it is heat-soaked. Often times, we deal with 90-degree weather-not just in True Street but also during local test and tune sessions. Couple the high ambient temperature with even hotter compressed air from a supercharger or turbo and it becomes difficult for a front-mount air-to-air intercooler to keep up," stated Burcham.
"There is no fresh air other than the 90-degree air running through the intercooler at low speeds, usually in the front half of the track. By the time the car really gets moving, the air and the intercooler are already heat-soaked." As the charge temps climb, performance falls off because the hotter air carries fewer oxygen molecules, and the ECU starts to pull timing because the raised inlet temperture and subsequent increased combustion temperature is more likely to cause detonation. Burcham has seen 3-4 degrees being removed in high gear because of the hot air.
Many blower kits come with an air-to-air intercooler or a small air-to-water unit (both of which are fine for most applications), but as the engines get more radical and the blowers get bigger, there comes a need for a more efficient intercooling system. An air-to-air style intercooler refers to air rushing over a heat exchanger to cool the boosted air down, much like a radiator does for engine coolant. An air-to-water intercooler is a heat exchanger that relies on circulating water (often ice water in race applications) to cool the air charge.
Burcham's solution for high-horsepower applications is a fabricated air-to-water intercooler that utilizes ice water to chill boosted air. The custom air-to-water intercooler is designed for '05-newer Mustangs and it replaces popular air-to-air coolers in the same location so the charge piping needs little-to-no modifications to fit. JPC can custom build an intercooler for other applications as well.
Burcham used a customer's '05 Mustang GT to show how easy the intercooler installs and its effectiveness when compared to the air-to-air 'cooler that was previously on the car. The black GT utilizes a popular combination at JPC-a Rich Groh Racing (RGR)-built 302 stroker engine with RGR-ported Three-Valve cylinder heads, a pair of JPC camshafts, JPC intake manifold, ProCharger D1SC blower (24 psi of boost), and everything else needed to make it all run smoothly, including a JPC return-style fuel system and custom tuning using DiabloSport software.
Baseline runs were made with the standard air-to-air intercooler; the GT produced 627 rwhp and 650 rwtq. Inlet air temperatures soared to 176 degrees during the short dyno pulls. Burcham said the test car's temps have gone as high as 250 degrees on track. The track always shows higher temps than chassis dyno pulls because of the longer running time. The ECU was yanking away 2 degrees of timing at the top of the chassis dyno pull and 4 degrees on the track. Total timing is set to 19 degrees for this application.
Installing the air-to-water intercooler is not a difficult task; the standard JPC cooler fits nicely in place of the air-to-air unit it is replacing. "Our standard intercooler is rated to 1,250 hp and it fits in the regular location. The intercooler used in this story is rated up to 1,500 hp and because of its size, we had to notch the frame to fit it in," says Burcham of the installation.
The JPC crew also added a larger ProCharger Race bypass valve because of the 24 psi of boost. From there, it was only a matter of bolting in the water cell, running the feed and return water lines from it, and mounting and wiring the Meziere WP136S water pump. The feed line is -16, which is split into two -12 lines at a Y-block up front and continues to the intercooler. Twin -12 lines exit the 'cooler and are combined at a Y-block to a single -16 return. This is because the intercooler is comprised of two separate cores.
The water cell holds 5 gallons of water and Burcham recommends filling it to about a third with water, and then stuffing four bags of ice in the cell. The Meziere pump circulates the water at a rate of 20 gpm.
On the dyno, Burcham logged the air inlet temperatures and noted the new intercooler chills the air down to just 75 degrees. Multiple back-up runs were made to verify the 101-degree reduction in inlet charge temps; each run was within a few degrees of 75. While the temperature was going down, the horsepower and torque was increasing. At peak, we saw a gain of 44 rwhp and 70 rwtq, thanks to the cooler air and increased ignition timing. The ECU wasn't removing any ignition timing and Burcham even safely added 2 degrees, after checking the spark plugs. The denser air helps keep detonation at bay, thus the ability to increase the timing.
Adding the ice to the cooler is very effective at the track (and dyno) but is debated for street use. Burcham summed it up: "We have toyed with the idea of adding a heat exchanger to keep the water cooler for strictly street cars, much like the Terminator, Shelby GT500, and Lightning vehicles. This application is more for track use, but I usually cruise around in my '05 Mustang GT with the water pump off and the still water keeps the temps at 80-110-depending on the outside temperature and as long as I don't lay into the throttle. When it's time to race, I simply flip the switch and the inlet temp comes down pretty quickly."
In conclusion, the ice/water mixture proved to be very effective on this Mustang thanks to the large blower and big boost. The JPC intercooler was better matched for the power levels of our test vehicle compared to the standard air-to-air intercooler that was on the car. As the blowers and turbos get bigger, so does the task of chilling the boost in order to get the most power out of your Mustang.