Catalytic Converter, 88 90q to 85 4kq?

[Huw Powell]

> Does anyone know if the cat converter from a 1988 90quattro will bolt on to
> a 1985 4k quattro? In order to get a smog certificate for my '85' 4kq I need
> a cat that functions (at least a little). Since I have an '88' 90q parts car
> I would like to pull the cat from it and use it. If I recall correctly the
> 4kq cat has the oxygen sensor mounted in it. I can add an oxygen sensor bung
> to the 90 cat if needed.

Um, yes and no...

I think the cat inlet flange is the same diameter.  The downpipe to cat
"funny angle" may even be the same between the two cars, BUT...

The 90Q cat is round, while the 4kq one is flat and wide, there may be a
problem there.

Also, the 4kq cat has an exit flange right away, the 90Q cat has about
18" of pipe that straightens out and meets the middle section with a
nice S/S butt joint clamp.

If you're willing to swap in the middle section as well, you might be
able to work it.  The 90Q middle is just like the 4kq middle, but with
less pipe at the front.

The 90Q cat does have the OXS mounted in it, so at least you won't have
to fiddle with that.

--
Huw Powell

http://www.humanspeakers.com/

http://www.humanthoughts.org/