Comments: I recently installed a Wetterauer chip in my 1997 A4 1.8T automatic and am very satisfied with the result. Subtle, but stronger and crisper performance to match the car's other fine attributes. 

In addition to synthetic oil, I decided I needed the benefit of some added cooling after engine shutdown. I investigated turbo timers, which run the engine for some time after ignition shutoff, but decided against this approach. The attraction to thieves of a running car with no one in it and the problems of leaving a running car in the garage precluded this choice. I decided instead to use a turbo timer to run the electric fan that Audi so conveniently puts just ahead of the turbo. I believe this approach has several benefits;

1. You get direct air cooling of the turbo and the catalytic converter, the two hottest components under the hood.

2. You get air cooling of the a/c compressor and starter motor, two very expensive components under the hood.

3. You cool the radiator witch, with the help of convection cooling, also helps water cool the turbo.

4. You greatly reduce the overall under hood temperature after engine shutoff.

5. There are no visible "kluge" add-ons.

The way I wired the HKS turbo timer in the driver's side dash is as follows;

1. Take off the fuse cover plate, remove the knee bolster (4 screws) on the driver's side and the A post cover panel (2 screws).

2. Position the HKS unit sideways in the neatly supplied opening above the fuse panel. Pass the wire bundle over the aluminum bracket that provides knee crash protection and drop the leads down into the foot well. I made up a little sheet metal bracket to hold it steady and mounted it using the upper fuse panel screw.

3. Connect the TT handbrake wire (gray) to the HKS unit ground wire and connect the ground wire to the common ground point on the A post.

4. Connect the TT red power feed to the terminal strip along the bottom of the main relay panel. There are many other red leads here. (Remember you must disconnect the battery ground lead first.)

5. Connect the two main TT outputs (the green and yellow ignition leads) to the black and yellow wire on the green plug on the left A post. This is the feed to the power windows. The wires here are different sizes so you can either strip the black and yellow wire and then solder and tape-wrap the TT lead to it or, alternatively, you can extend the TT leads with a smaller wire and then use the crimp on connector that HKS gives you.

6. Buy a light switch relay and connect the coil to the TT (blue) auxiliary output and ground the other side to the common ground post.

7. On the auxiliary relay panel (behind the main panel) remove the fan relay. It's labeled 215 and is in the number 3 position (you might not see the number 1 position so you'll think it's number 2). Pop the relay socket out and unlatch the 40 and 50 amp fuses. This allows you to drop the relay socket out from behind the relay panel and then connect the
switch output leads of your new relay to the red and blue (relay pin 30) and red and white (relay pin 87) leads on the existing relay socket.  (Use the neat crimp on connectors that HKS supplies or buy similar ones.) For the electrical geniuses, what you've done is wired the new relay contacts in parallel with the existing fan relay contacts. The existing fan relay is normally operated by the a/c unit or a temperature
switch in the radiator.

8. Secure the new relay to the auxiliary relay panel with a nylon tie.

9. You're done. Set the TT, I use about 4 minutes. Remount the panels and connect the battery.

Some added nice features of this arrangement are that the fan does not start until you open a door. So if you stop the engine, stay in car and then start again, you're not unnecessarily running the fan. Also (since the TT back-feeds its main outputs) the power windows and sunroof are operational until the fan stops, even if the car doors have been opened.  (Have you ever been refueling the car while your passenger cooks because they can't open a window?)