all contributors: K.J. Jones
Saul "The Surgeon" Gutierrez of Extreme Automotive secures Ford Racing Performance Parts' '05-'08 Mustang GT 85mm cold-air kit (PN M-9603-GTB; $669) to the front of our stock '07 Mustang GT California Special. Unlike other CAI systems for S197 'Stangs, the new "Bullitt cold-air intake" (the bolt-on accessory is standard equipment on Ford's '08 Bullitt Mustang) features a front-feeder design in which air is forced into the filter and tubing directly from the front of the Mustang, as opposed to being pulled into the engine compartment through the driver-side fender.
If we were to ask a random group of '05-'09 Mustang GT owners for their thoughts on what the top-five first mods are for S197s, it's a safe bet that a cold-air intake system (better known as a CAI kit) would be included in each response.
Improving the air's volume and flow path into a new Mustang's Three-Valve engine is one of the best methods of increasing horsepower and torque. Installing a CAI system has proven to be the best way to achieve performance-enhancing air efficiency without spending millions.
It's sometimes hard to believe we've looked at so many different S197 cold-air kits over the last four years. Each system-whether installed and tested independently or with a group of additional budget-friendly bolt-on pieces-has supported the theory that cold air and improved airflow bump horsepower. Even so, one of the interesting factoids about the CAIs we've reviewed in the past is that none of them are approved by the California Air Resources Board, the mother of all clean-air organizations.
CARB has the responsibility of deciding which aftermarket performance parts are or aren't legal (smog-legal) for use in all 50 states. We don't know the criteria CARB uses to make its decisions, but based on what seems like its rejection of almost everything cool produced for 'Stangs (turbo systems, big-horsepower blowers, certain camshafts, nitrous, various headers and off-road exhaust pipes, and so on), we were surprised to hear that Ford Racing Performance Parts has once again beaten the odds.
So, if you are wondering about FRPP's latest CARB-approved winner (we've already detailed the company's smog-legal upgrade supercharger for Shelby GT500s), it's an all-new CAI for '05-'08 'Stangs! The new setup, formally referred to as the '05-'08 Mustang GT 85mm cold-air kit with premium CAL (PN M-9603-GTB; $669), is basically the same air-intake system that highlights the '08 Bullitt Mustang's engine bay. It's perfect for enthusiasts who want a modest performance gain without having to install noncompliant pieces (the key to achieving CARB's OK is a hydrocarbon trap inside the intake tube). Another plus for the kit that Editor Steve Turner has dubbed "the Bullitt CAI" is that Ford supports it with a factory warranty as long as the kit is installed by an authorized Ford or Lincoln Mercury dealer.
The bone-stock engine managed 264 hp and 268 lb-ft of torque in its baseline run, which we've come to acknowledge as par for the course with stock S197s.
Fuel requirements are important elements of CAI upgrades. With the Bullitt kit in place, Mustangs that ran on lower-octane gas (87 or 89) before the upgrade are now married to a 91-octane minimum thanks to the airflow increase that the new system promotes. VIN-specific PCM calibrations that compensate for increased air and octane are available from FRPP, and they're loaded in a 'Stang's PCM using a handheld Pro-Cal flash tool.
For this effort, we're using a stock California Special edition of a Three-Valve '07 GT. The irony is somewhat appropriate, since Cali is the state that seems to always get shortchanged when it comes to CARB's decisions on performance parts.
After establishing a bone-stock baseline horsepower value on Extreme Automotive's chassis dyno, Saul "The Surgeon" Gutierrez handled the 10-minute bolt-on aspect of the test and reran the car to see what the Bullitt CAI is made of. As is par for the course with cold-air systems on stock S197s, the power gain was modest, but the system really does look sano. Thanks to that lining in its tube, the Bullitt CAI is the only kit out there for new Mustangs that CARB and Ford both endorse.
Click here for the S197 Mustang GT CAI dyno chart
The Bullitt CAI includes all of the necessary pieces (hoses, clamps, screws, and so on) for a quick and simple installation. It bolts directly into the stock location without the need for cutting or making far-out mods. We really dig the molded-plastic airbox piece and its painted-on Ford Racing logo. Unlike the metal barriers that are common to other systems, the Bullitt system's plastic panel seals to the hood more completely and helps dissipate underhood heat away from the filter instead of containing it in the filter's area. | 
Removing the stock air-intake system requires handtools and takes all of 5 minutes. | 
Saul has FRPP's cold-air hardware installed on the California Special in about the same amount of time it took to remove the stock stuff. Check out the conical air filter. The filter is disposable, and there's a hydrocarbon trap inside the intake tube, which is one of the main reasons why CARB is OK with this system being used on street Mustangs in all 50 states. |
Bullitt CAIs include a new 85mm mass air meter. Our GT's stock sensor is retained, and Saul installs it in the larger tube using the included hardware. | 
The Pro-Cal tool is used to flash and reformat the Mustang's stock PCM with fuel and timing changes to allow the engine to operate normally, despite the influx of cold air. |  |