The Ford Focus is a compact economy car that comes with about 140 horsepower (hp). While this may be enough power for most drivers, there are ways that you can boost the horsepower easily. One option is the installation of a cold air intake system. You can have a performance shop do it, but it is an installation that any level car enthusiast can do at home. The cold air intake system will add nearly 10hp to the Focus engine.
Turn off your Ford Focus and open the engine bay.
Use the screwdriver to remove the red cable that connects to the battery.
Remove the hose clamp from the Focus throttle body and pull up on the coil pack and throttle body linkage covers to remove them. Disconnect the wire that runs to mass air flow sensor on the stock air box.
Pull the Ford Focus stock air box out of the engine bay. Remove the hose clamp that secures the mass air flow sensor to the stock air intake and pull the sensor out of the air hose. Locate and remove the rubber grommet from where the stock air box was sitting.
Remove the rubber mounting bumper from the stock air box's mount. Replace the rubber grommet and bumper with the ones that came with your cold air intake kit.
Connect your cold air intake's tube to the cold air intake bracket before placing it into the Focus engine bay. Insert the other grommet into the cold air intake's tube.
Place the silicone connection hose and secure it with one of the provided hose clamps. Place the cold air intake tube that has the bracket mounted to it and connect it to the silicone hose. Tighten the other side of the hose clamp.
Connect the mounting bracket from the cold air intake hose onto the engine's valve cover with the nut and bolt provided in the kit.
Cut off two sections of the hose mender that came with your kit. Insert the hose mender into the small inlet in the cold air intake hose. Insert the crank case hose into the hose mender.
Bolt the "L" bracket onto the heat shield using the ratchet. Place the foam edge trim around the heat shield. Connect the heat shield to where the stock air filter was bolted.
Connect the mass air flow sensor onto the filter adaptor that comes with your kit. Place the small silicone connection hose onto the mass air flow sensor and tighten the clamp closest to the sensor.
Connect the mass air flow sensor to the cold air intake hose and tighten the outside hose clamp to secure it. Connect the mass air flow sensor electrical wire to the mass air flow sensor's wire harness.
Place the filter onto the end of the mass air flow sensor and tighten its hose clamp with the screwdriver. Place the coil pack and throttle body linkage covers back onto their respective areas. Reconnect the battery cable and close the engine bay.