How does Heat Exchangers work?
 

Searched all over and couldn't find how/why it works.

Thanks.

Basically, there is sheet metal surrounding the exhaust headers. Creates a chamber of hot air. Then ducts carry the hot air through tubes, into the interior of the car. The engine cooling fan and, in later cars, auxillary fans, help move the hot air into the cabin.

Its very simple.
The blower motor on top of the engine blows air across the exhaust manifolds and into the cabin.
The 'heat exchanger' is an exhaust manifold with tinware enclosing it.
In the pic below air is blown into the hole facing you, over the manifiold piping, and out through the chimney looking bit at the back. From there it goes through a flap and into the car.
Hope this helps.

http://forums.pelicanparts.com/uploa...1094687566.jpg

Ahh...I thought they were related to emissions rather than air circulation.

Thanks.

You might be thinking of thermal reactors, which were used on some 75-77 911's.