73 S3 mystery feature…What is this?

Getting to know my S3 and noticed in the passenger footwell a disk attached to the forward wall.

Still scratching my head….

It’s the footwell fresh air ventilation system. The complete system should have “Pull air” control levers on the A posts to control the arflow from the picture frame triangular collector boxes. The comes to those from the air dams either side of the bonnet grille.

kind regards

Marek gave you the correct answer.

I am restoring my Series III and have it in pieces – this photo may help visualize that vent and other stuff hear it

  • The circular vent you asked about is at 9 o’clock on the photo
  • The pull handle (unscrewed from the body but with the cable attached) is dangling on the right side on the photo – you can see the mounting holes on the vertical panel at 3 o’clock on the photo
  • The black-wrapped wiring harness with white tracer across the middle of the photo is near the beginning of side wiring harness and connects to the bulkhead harness just out of frame
  • The holes in the front of the footwell are to mount the charcoal canister and (in my case) the amplifier for an after market stereo system
  • The opening at 10 o’clock on the photo is on top of the footwell and is where two A/C hoses pass into the engine bay through the black plastic cover (if you have A/C)
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Here are the scoops - at 10 o’clock and 2 o’clock hanging off of the picture frame - see the three washers sitting on the left hand scoop grille.

and here is the control mechanism - it’s a bicycle brake cable

Between the scoop and the firewall hole is a 2" flexi hose which was also used on the XJS aircon.

kind regards

Sure some nice cars good job Merek

This is all very helpful guys. thanks!. And Marek, where did you have your engine rebuild done. I’m considering doing something like this in the winter and looking for potential providers. Unfortunately, I don’t have the skills and would like to upgrade the engine and gearbox to 5 speed. Also, what is the black box just under the RH hood latch pull?

Except for a bit of welding, I did it all myself. I am in the UK, so you will have to look for someone more local in any case.
The black box is an Inertia switch from an XJS. The car is fuel injected, so it has a cut-off in case of an accident.
There is plenty of advice already posted about 5speeds. A Jag box with a compact type-A overdrive is a drop in replacement.

kind regards