Talk to me about Catalytic Converters for an '86?
 

Narrowing down some runnability issues I think that my CAT is breaking apart. It's making noise when the car is warmed up like a rattling heat shield (I've had the car running on the lift so I know the sound is from the CAT)

So... according to Rockauto there are three possible cats available for my car - none are 50 state but I don't live in CA so that's fine.

My car is an early 32v with dual exhausts out the back. I also have an AIR pipe that comes up near the flange of the passenger side.

I don't see in the pics any that have the air pipe. I'd like to get the Bosal 0991562 but that doesn't have any pictures at all.

The only one I have seen that looks close is a DEC P02608. That appears to have the right pipe.

http://www.ebay.com/itm/160716368355?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
Anyone have experience doing this job? I would prefer to not spend $2500 on an OE Porsche part since I don't drive the car that often.

Any advice appreciated!

Thanks!

Here ya go:

https://www.amazon.com/Walker-80830-...onverter+80830

This is 50+CA CARB approved, direct fit.

The difference between generic non CA and CA approved will be lifetime, the generics, expect about 2yrs of use before it burns out.

So that's just the CAT part. I'm hoping to get the whole system with the downpipes and air pipe.

...you didn't say that. You said you needed a new cat.

What exactly are you missing?

Sorry. Nothing is missing. It looks like at some point someone welded new mid pipes to a new (or maybe original) cat. So the exhaust from the manifolds to the cat is a little buggered, and now it appears the cat is rattling so may be going bad.

I saw that it's possible to get the cat from the manifolds all the way to the mid pipes, as you can see in the link I posted. In fact, several companies appear to make these units, and claim they fit, but they do not show pictures of the air pump pipe as my system has.

So I'm wondering if anyone has used one of these aftermarket CAT's, and which one might work in my application.

Thats just it....the CARB cat is SO cheap, use it, and WILL come with a port for your air pump.

As for down tubes, and post cat hardware, should be easy to source via 928intl.

Others will say "dump the cat", but since the future is not known, maintain the cat, maintain future sale and compliance flexibility. It's cheap.

Do you have an x-pipe? Get an x-pipe with hi-flo cats from Roger 928 R'US if available or from 928Intl. I have a set on mine, worth it. Fabrication wasn't bad either, $250 at a Porsche specialty shop not too far off from me. You could probably get it done same price or do it yourself.

Just to make sure....
I didn't see you mention if your shark was auto or manual.
I have a rattling that occurs only at park. this is caused by flex plate rivets getting wobbly as they either get worn or wallow out the holes in the two halves of each flex plate. There is even a Porsche tech memo on this.
You probably have yours isolated, but I thought I should mention this.
Oh, and it sounds just like a heat shield rattle.

It's a manual. I thought heat shield too, which is why I took mine off and did some repairs on a couple broken tabs.

But the rattle persisted, and I was able to isolate it to the passenger side of the two CATs :(

I went with headers. I have the factory cats, downpipes complete. Came off of an early auto "86. Not sure if they are compatible. Sorry about pic. I had them wrapped up hanging in the shop. If interested text @ 816.853.4663

^^^ all '85 and '86 32v are the same (compatible) ^^^

'86.5 is when it changes to an S4 type exhaust and is more of a Duel exhaust as the Resonator is not shared (duel resonators too) into a single aft muffler.

My experience with aftermarket cats, mocked up in a direct fit configuration or not, is that they last 1-2 years. I bought a CARB-approved set like the one pictured and got one good test result out of it. It failed NOX less than two years later. I was able to locate a used factory cat set. Hard to come by as it is illegal to sell them in CA.

Which headers did you go with? I've been trying to find some that are reasonably priced now for a couple months with no luck.

Bit the bullet...MSDS jet coated

Historically there are only four options:

1. Devek - if you find someone selling these for cheap they are probably stolen or they have no clue what they have.
2. MSDS
3. Greg Brown - If you don't know how much these are, don't ask - but they are worth every penny. I plan to put these on my supercharged 81.
4. OBX - a genuine Chinese knockoff of the MSDS headers

The 5th option is the 85/86 manifolds. Nobody has ever posted an honest to goodness back to back comparison of these VS headers on a 16V (at least that I've ever seen) but they are the best bang for the buck on a budget when trying to clean up the exhaust. They are also usually easy to find used, for cheap.