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S197 Mustang Intercooler - New-School Cool
Steeda's heat exchanger brings the big chill to supercharged S197 GTs and Shelbys
Horse Sense: The best way to comprehend the inefficiency of a heat-soaked supercharger is to imagine trying to move a ship's anchor that's stuck 100 feet below the ocean floor. Basically, hot air has the opposite effect on an engine than that of cold air-it hurts performance. In this case, heat inside the blower and the air charge it generates all but extinguishes an engine's ability to make good power.
Cool, crisp inlet-air temperature is a friend to all internal combustion engines. To put it in better perspective, cold air, as inlet air is commonly called in most high-performance circles, makes horsepower. We have no argument for that sentiment. We're always looking for and trying out new methods of increasing or improving the air that a naturally aspirated or power-adder-assisted Mustang engine takes in.
Air enhancement for S197s has been the hot ticket lately. The cars are super popular, and the aftermarket has seen to it that all types of cold-air intake systems, superchargers, turbos, and nitrous sets are readily available for the new '05-'08 'Stangs. For this exercise, we're looking at Steeda's new high-capacity heat exchanger (PN 555-3706; $449.95) for factory-supercharged Shelby GT 500s and S197 GTs that get additional oomph from positive-displacement blower offerings of Roush and Magnacharger.
Air-to-water intercooling is the primary method of lowering air temperature in supercharged '05-'08 Mustangs equipped with these types of superchargers. Blower-mounted intercoolers for both systems use engine coolant that passes through their cores to lower charged air's temperature just before it enters the engine.
Often, especially when additional mods are made to increase horsepower, a Shelby's stock intercooler (or one included with a Roush or Magnacharger unit) loses its ability to disperse heat and maintain efficiency, despite the presence of radiator-style heat exchangers mounted behind the front bumper that serve as additional independent cooling systems for the blowers.
The root of the situation is, stock-type heat exchangers are too small, and they can't keep up with the amount of heat a supercharger generates and stores once a supercharged 4.6 or 5.4 makes serious steam.
The new Steeda heat exchanger we're installing is much bigger than the OEM Shelby GT 500 or those included with aftermarket units. It will increase superchargers' cooling by more than 160 percent, as flowing coolant will experience huge reductions in temperature, thanks to its increased size.
David and Tedd Siegel of Total Mustang Supply spotted us their lightly modded (CAI, pulley, and tune) Shelby GT 500 to use as the subject 'Stang in this effort, and Steeda's Steve Chichisola is our installer. Bolt-in time for this deal is approximately two and a half hours-it may take longer on Mustang GTs, as a few minor modifications are required. We feel the installation should be performed by 'Stang techs in a fully equipped shop. However, any mechanically adept Shelby owner probably will be able to take care of this install in the driveway, as long as a buddy or two is around to lend a hand.
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While we were at Steeda, we decided to check out the company's upgraded cold-air kit (555-3135; $370.45) on another GT 500.
The new system includes many of the same components found in Steeda's original CAI for Shelbys, but the major difference is that this new deal features an advanced inlet elbow that further streamlines intake airflow and clears a Shelby GT 500's strut-tower brace without compromising any of that improved airflow. We're told it has, by itself, produced an extra 12 rwhp on a Shelby).
Having 12 more horses is nice, but most of us are looking for the bigger numbers. When combined with an SCT tune (which Steeda says is now mandatory, by the way), the improved Steeda cold-air kit has shown power gains of as much as 97 hp at the back tires. Throw one of the company's blower pulleys in the mix and the potential is there for more than 140 extra charging ponies without sacrificing vital frontend stability that definitely will be needed.