|Tech Article Title
|1.8T Chip Upgrade & HKS Turbo Timer
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
5. There are no visible "kluge" add-ons.
The way I wired the HKS turbo timer in the
driver's side dash is as
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
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?)