Jet Jockey/A4 Pilot

Ok several weeks ago I pulled the complete HVAC system out of the car to put it on a severe diet. At the time the <b>HVAC weighed just over 20 lbs.</b>

So now after all the weight trimming I'm happy to announce the HVAC system (what's left of it) that's going back in <b>weighs only 9.5 lbs!</b> That more than a <b>50% weight reduction.</b> I wish my diet was that easy.


Here's the complete assembly prior to going under the knife.

<img src="http://i17.photobucket.com/albums/b79/mlab601/Car-HVAC-Weightreduction-Jan-26-200.jpg">


Here we have the underside forward facing outlet(s) for the feet. From here it went to other ducts that split the air toward the feet.

<img src="http://i17.photobucket.com/albums/b79/mlab601/Car-HVAC-Weightreduction-Jan-26--1.jpg">


This is facing up and centre at the centre ducts (closed).

<img src="http://i17.photobucket.com/albums/b79/mlab601/Car-HVAC-Weightreduction-Jan-26--2.jpg">


Centre ducts now open. These ducts are going to be completely eliminated by cutting them off and trimming down the excess plastic.

<img src="http://i17.photobucket.com/albums/b79/mlab601/Car-HVAC-Weightreduction-Jan-26--3.jpg">


Behind and above he centre ducts are the defrost ducts (closed).

<img src="http://i17.photobucket.com/albums/b79/mlab601/Car-HVAC-Weightreduction-Jan-26--4.jpg">


The defrost ducts now open.

<img src="http://i17.photobucket.com/albums/b79/mlab601/Car-HVAC-Weightreduction-Jan-26--5.jpg">


Then I split open the whole assembly. The first major component to be removed will be the AC evaporator (relatively heavy).

<img src="http://i17.photobucket.com/albums/b79/mlab601/Car-HVAC-Weightreduction-Jan-26--6.jpg">


Now that it is split open and the AC evaporator removed you can see better the whole structure. I will now begin the surgery and remove the front portion, the centre vents.

<img src="http://i17.photobucket.com/albums/b79/mlab601/Car-HVAC-Weightreduction-Jan-26--7.jpg">


Here's the picture of the front portion of the assembly minus the front vents and minus some excess plastic.

<img src="http://i17.photobucket.com/albums/b79/mlab601/Car-HVAC-Weightreduction-Jan-26--8.jpg">


Side view. As you can see no where was safe for trimming the excess plastic.

<img src="http://i17.photobucket.com/albums/b79/mlab601/Car-HVAC-Weightreduction-Jan-26--9.jpg">


After the cutting, came the sealing. I do not want any air to escape or come out of the assembly at undesired locations. So the front was sealed, mainly the centre vents are no longer needed and are part of the defrost ducts. So now the air will be concentrated to the defrost ducts.

<img src="http://i17.photobucket.com/albums/b79/mlab601/Car-HVAC-Weightreduction-Jan-26--10.jpg">


Here's how the system works to get some heated air into the ducts. Depending on how much hot or cold air you want through a series of ducts and temperature sensors the proper ones will open and close accordingly. Both the AC condenser and heater core sit basically one behind the other so it is easy to modulate the temperature. Here we are looking from behind the unit into and towards the front side or cabin side. The heater core sits behind and below the flaps. You can see on the right side the opening where the core can be removed and installed. Both the upper and lower flaps are linked together but are separate from the left to the right side. So I purposely set the left side to the full cold position and the right side to the full hot position so you can see the difference. The right side's lower flap is open and the top one is closed. This guides the air down and through the heater core and up to the centre vent and/or the defroster. On the left the bottom flap is closed deflecting the air upwards and through the open ducts because the upper flap is open, again to the central vents or defrost area.

<img src="http://i17.photobucket.com/albums/b79/mlab601/Car-HVAC-Weightreduction-Jan-26--11.jpg">


Now I'm going to trim the other part of the assembly.

<img src="http://i17.photobucket.com/albums/b79/mlab601/Car-HVAC-Weightreduction-Jan-26--12.jpg">


As you can see a few places were trimmed and other areas may get done at a later date when I see how the whole assembly fits in the car and is being held in position. The heater fan/motor was reinstalled too.

<img src="http://i17.photobucket.com/albums/b79/mlab601/Car-HVAC-Weightreduction-Jan-26--14.jpg">


The whole assembly was reinstalled and put back together.

<img src="http://i17.photobucket.com/albums/b79/mlab601/Car-HVAC-Weightreduction-Jan-26--15.jpg">


Side view of the heater core and its pipes back in place. You can clearly see the centre vents taped up and I decided to keep the small levers that were originally electrically controlled to adjust the defroster flaps. I'll try to rig myself a manual control to open and close the defrost as I wish and in this way control the heat too.

<img src="http://i17.photobucket.com/albums/b79/mlab601/Car-HVAC-Weightreduction-Jan-26--16.jpg">