exhaust what is it

[eric35II]

just purchased a 74 35 II... it has an a4. at the exhaust it goes into some kind of galvinized pipe. there is also a hose that goes from the exhaust manifold into this pipe. there is heat insulation from the engine to this pipe. on the other end it does a 90 degree turn up and then does another 90 and into what i think is a muffler. what is the function of this pipe ??

thanks
greg

 

[rgoff]

Sounds like the same as my 1973 E27.

That's referred to as an exhaust riser. The purpose is to mix the very hot exhaust from the engine (the wrapped pipe) with the less hot cooling water from the engine (in the small rubber hose). This cools down the exhaust fumes before they exit the riser. The pipe from the riser to the muffler probably isn't wrapped with any insulation, because it's been cooled by the water.

One word of caution. Every 5 years or so, my riser clogs up and the engine (an Atomic 4) starts but dies when given any gas. The last time it clogged the pipe "L" at the bottom of the riser was packed with carbon.

 

[gareth harris]

Greg - Some time back another 1970s E35 owner posted some pictures of his work replacing the exhaust system you describe, it should be in the archives.
I have done the same job myself, but no pictures yet.

Gareth
Freyja E35 #241 1972