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Apexi Turbo (Auto) Timer Install on Audi A4, 1.8T

Prior Experience: None
Cost: Cost of TT
Time: 60 Minutes
Discuss this mod - Here

For turbo vehicles, it is good practice to leave the vehicle running to allow the turbo to cool down before keying off. If the turbo is very hot, and the vehicle is keyed off, the coolant and oil will not be pumped through the turbo. If the oil sits in the turbo, it can bake in and damage the oil and the turbo. Some people prefer to let the car idle while they are in it - and just wait for it to cool. Others choose to install a turbo timer to do the job for them. Just incase you don't believe me, here is a scan of the owner's manual:

 turbo timer  

SUPPLIES - You will need the following tools for this install.

Apexi Turbo (Auto) Timer
Panel remover tool
8 and 10 mm nut drivers
Wire strippers and snips
Assorted screwdrivers
Circuit Tester/Multimeter

NOTE: Up until recently you could not operate the vehicle's immobilizer on any B6 Audi while the vehicle was running. So when the turbo timer was operational, you could not lock you doors or set your alarm with your key FOB. You would have to put your key in the door and turn the key. This has recently been overcome by the Turbo Timer Companion Lite which I installed with this turbo timer. The writeup for this install is located here: Turbo Timer Companion Lite Installation Procedure

turbo timer  

The first thing to do is to remove the fuse panel cover on the driver's side of the vehicle

You can do this by simply inserting your key into the slot and prying it off

turbo timer  

Next remove the 8mm bolt on the side of the panel

Please, no comments on the air fresheners. Only the top one is new.

Next unscrew the two 8mm screws under the kick panel - under the steering wheel
turbo timer   turbo timer

After the bottom two screws are out, pull the panel at the upper trim to disconnect it

  turbo timer

Lower the panel to the floor, and disconnect the OBDII connection and the floor light.

Remove the kick panel.

  turbo timer

The Apexi turbo timer can be installed several different ways. It is designed to take readings from the O2 sensors to calculated how long the timer should run for after key off. I decided not to do this, as it is not necessary if you just program a time such as 30 seconds in. This is more than enough time for every day driving

The apexi also comes with the option to buy a special wiring harness so that its is more plug-and-play. However, these harnesses are not readily available for audis, so we have to make due with what is here.

The way it will be connected is as follows.

turbo timer

The basic functions of the wires go something like this:
Red: This goes to constant 12V. It supplies the TT with power, and is used to keep the ignition line at 12V after key off. It must be connected to a good 12V source that is capable of sourcing current
Green: This wire gets connected to the ignition switched 12 V source. When the turbo timer detects a drop in this voltage, it will source voltage to it for the amount of time programmed in the timer. This will keep the engine running.
Black: The ground for the turbo timer
Grey: This wire gets connected to the emergency brake switch. It should have 12V to it when the emergency brake is DOWN. This will turn off the turbo timer if the brake is put down. If someone were to try to get in your car and drive it away while the TT was running, they could keep adding time to the TT until they got to where they needed to go. By connecting this wire, they will turn the car off when they release the emergency brake. This is a security feature and should always be used.
White: The white wire is used to get the O2 sensor readings. Like I already said, I will not be using this wire
Blue: I am not sure of this wire's function. I believe this should be connected to a switched 12V source which is live when in ACC (instead of run). I did not connect this wire in my install, but will investigate its purpose.


Now that you know what the wires do, lets start installing the turbo timer. First, disconnect the 12V battery.

Next, locate the switched 12V wire - it is the thick black wire on the left side of the steering column - shown here in the picture.

NOTE: You should use your multi meter or voltage tester to confirm this. It should have 0V when the key is off, and 12V when the key is in Run/Acc.

  turbo timer

You need to tap the Green wire into this switched 12V source. As I mentioned earlier the Apexi TT comes with a harness attachment which we cannot use in our cars. Although it is useless, I did not feel like cutting it off.

I used some spade connectors to connect to the harness. It looked like the picture to the right before I sealed it up.

I used brown wire to extend both the Green and Red wires. So you will have to keep track of what is what in the pictures.

  turbo timer
turbo timer  

I used a razor to remove the insulation from the ignition line, then wrapped the Green wire around the exposed ignition wire. I typically try to avoid cutting the harness on the vehicle, so I find this method works great.

After you have connected the green wire, solder and tape the connection so it is solid.

turbo timer  

After you have connected the ignition wire, connect the Red wire to the constant 12V source. If you look under the kick panel, you will find many RED lines going to 12 V sources. I used the following one.

Once again, I extended the Red TT line with a brown wire and a ring terminal.

Use your 10mm socket to remove the nut and attached the Red TT line.


Next you need to connect the ground. I have been using the same ground for a couple applications (boost gage, etc) so I decided to use it again here. It is inside the fuse panel, and works well.

NOTE: You should sand the black paint off the ground so you have a good connection to the chassis here.

  turbo timer

The last connection you need to make is the White wire to the parking brake. I ran the white wire under the kick panel and down the center console (just tucked it under the center console at the bottom).

Be sure to zip tie the white wire up, so it is not in the way of the pedals or any moving parts

To get to the parking brake connection, you may have to extend this white wire. I extended mine with a yellow wire that I had laying around.

  turbo timer
turbo timer  

To get to the parking brake switch you need to hop in the back seat and remove the ashtray. Just open the ashtray and pull up on it. It will pop out


After the ashtray is out, you have to remove the seat heater controls. If you don't have rear heated seats, you wont have to worry about this which is good. But at the same time, you don't have rear heated seats which sucks.

To remove the controls, grab them at the corners I am pointing to, and roll it towards the back seat. You will understand it when you see it.

  turbo timer
With the controls removed, you will be able to see the parking brake switch. There is a brown wire, and a brown wire with a white stripe. You want to tap into the brown wire with the right stripe to get the needed functionality.
turbo timer   turbo timer

After you have made all of the connections, you can secure the turbo timer box and controller wherever you like. I double sided taped my turbo timer box to a controller that was under the kick panel

I have not decided what to do with the Apexi Controller just yet - I will update with pics when I square something away.

Here is how I mounted the box though

  turbo timer

After everything is squared away, ziptie the wires in place and put the kickpanel back together. Connect the battery, key the vehicle up and enjoy your new turbo timer. Be sure that all of the functions work properly - especially the emergency brake cut off switch.

If you want the door locking functionality, check out the Turbo Timer Companion Lite Install

Good Luck!

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