Muscle Mustangs & Fast FordsHow To Engine
All About Intercoolers
Boosting Your Engine Is Fun-You Can Do Better With An Intercooler
Air-to-water charge coolers are usually heavier than air-to-air systems because of the additional components that make up the system-fluid, circulation pump, radiator, and plumbing. Though they may be heavier in weight, air-to-liquid charge coolers generally feature lower overall pipe and intercooler length, which can reduce turbo lag.
"Running coolant hoses is far easier than large-diameter air tubes, and in the case of a crash, there is less radiator up front so it's better protected. It won't incapacitate the engine if it's ruptured (if damaged, air-to-air wouldn't run), and it doesn't block the A/C condenser and radiator as much as an air-to-air," notes Kershaw.
The air-to-liquid setup seems to lend itself better to racing applications, because the fluid reservoirs can often be filled with an ice water mixture that can drop intake temperatures well below the ambient air temperature. The air-to-air crowd does something similar in that they spray nitrous oxide or carbon dioxide on the front-mounted charge cooler core to further reduce intake-charge temperatures. The reduction in intake-charge air temperatures is quite substantial with either design.
"On the Lightnings, we saw an approximate 100-150 degree drop in inlet temperature depending on vehicle speed versus engine load," says Kershaw.
In addition to supplying the engine with more air that it wouldn't have otherwise, the resultant internal engine temperatures drop as well, which allows for a more advanced and more powerful ignition-timing map.
As previously mentioned, the late-model SVT and Shelby products all use air-to-liquid charge coolers from the factory, and the aftermarket has produced a plethora of parts to make these systems more efficient. You can extract more power from the factory systems with these components, but more importantly, they provide proper cooling increases that support higher power levels. Companies like Fluidyne, Afco, Canton, Steeda, Precision Fabrication, and others all make high-performance heat exchangers and/or reservoirs that provide superior cooling and capacity, and most parts are drop-in replacements for the stock pieces.
Back in the mid-'80s, it was the technologically advanced Mustang SVO that led the way in forced-induction for the Mustang market. By the late '80s, the centrifugal supercharger aftermarket came alive, and it wasn't long before the benefits of charge cooling were integrated into the supercharger systems. Accessible Technologies, better known as ATI ProCharger, came to market with an intercooled supercharger kit for the Fox-body Mustang in 1994. It featured a two-core air-to-air intercooler, and offered a three-core unit as an upgrade.
"With intercooling, we could reduce the charge air temperatures dramatically, increase air density, and safely run more boost," says ATI's Ken Jones. "Charge air temperatures are reduced by approximately 90 degrees at 9 psi-about 25 degrees above ambient air temperature." ATI has kept with the air-to-air charge air cooler and uses them in the company's latest products. "Air-to-liquid coolers not only offer less heat reduction/temperature drop to begin with, but they typically heat up after repeated pulls and power fades badly," says Jones.