A turbo timer protects a car's turbo from overheating after a session of hard driving. When the engine is shut off active cooling ceases, but the temperature in the turbo may rapidly rise without continued cooling and cause damage from hot oil or excessive carbon build-up. After you have exited the car, a turbo timer will idle the engine until the turbo has cooled down. Turbo timers have a small LCD interface that you can mount in the dashboard and use to adjust the various settings. For safety, the timer has the option to connect to the parking brake to ensure the car won't roll away while idling. Some of the tools you need will vary from car to car. Remove the negative terminal from the car battery before beginning.
Find an appropriately sized spot on the dash where you can install the timer display. Look for blank button placeholders or any unused space in the dash console. When you've found a good spot, pry out the dash components using a flat-head screwdriver to access the wiring harnesses. If necessary, drill a hole behind the turbo timer large enough to fit the wires from the timer through. You can use double-sided tape or neoprene to help secure it.
Access the ignition harness. Depending on the car, you may need to remove multiple dash or steering column panels until you can find the large bunch of wires connecting to the ignition switch.
Check to make sure you removed the negative terminal from the car battery, then remove the tape binding the wires together and use the tap-in connectors to splice the appropriate wires together in accordance with the turbo timer manual. If needed, route the wires to the back of the turbo timer and connect them to it.
Connect the turbo timer to the speed signal sensor by running the power wire along the backside of the dash until you locate a hole in the firewall separating the engine compartment from the interior. If you cannot locate a hole, use the drill again to create one. Feed the wire through the hole and secure it along the perimeter of the engine to avoid damage from hot components. Identify the correct location for the speed signal sensor using a wiring diagram for the car or the turbo timer's instructions.
Use a tap-in connector to splice the speed signal wire and turbo timer wire together. Reassemble the dashboard, reconnect the battery terminal, and start the car. Turn the ignition off to verify that the timer keeps the car idling and is functioning correctly.
