Project Mazda 323 GTX: Part 4
Off the car, it's easy to see how simple the Road/Race boost control actually is. It connects to the GTX's stock vacuum system in three places: (A) The short line picks up the pressure source from the GTX's intercooler pipe. Inside this line is a cleverly designed restrictor, which maintains the correct pressure ratio downstream of the T fitting, ensuring the wastegate opens at the desired boost. (B) The wastegate actuator line is plumbed into the stock location as well. (C) This line routes air back into the intake downstream of the airflow meter. View Related Article