Alfa Romeo Forums banner

1 - 18 of 18 Posts

·
Registered
Joined
·
325 Posts
Discussion Starter #1
I'm working on removing my exhaust system and noticed that I do not appaear to have a hanger going from my catalytic converter to the bracket near the transmission mount. I can see where there are remnants of where one came out of the cat in the area of the bracket but it seems to have disappeared.

I just want to verify that S3 cats do have a hangar from the cat to the bracket near the tranny mount.

I don't want to completely remove the center muffler if it means all the weight will be on the manifold connection to the motor. I may rig a jack like rig for temporary support for replacement of the mufflers.

Has anyone successfully fashioned one (cat hangar to tranny mount bracket)? I don't mind the expense of a new cat if it isn't working right but not so much if it just does not hold properly.

Thanks in advance-M5
 

·
Registered
Joined
·
2,045 Posts
The original downpipe/cat had a welded on hanger mount. If yours is gone it broke off or was remoed by ??? Only way I know of to replace it is to have one fabricated and welded on by a muffler shop. Any kind of bolt on mount strap is bound to vibrate loose eventually.

Robert
 

·
Registered
Joined
·
28 Posts
If you're doing exhaust work which includes removal of the resonator (mid muffler), AND your shop fashions a proper bracket to brace the area that would have been the resonator, you dont need to worry about cat bracing, the brace at the resonator will hold the entire assy.

The car sounds great, btw, with just the rear silencer.
 

·
Premium Member
Joined
·
1,577 Posts
cat downpipe

After the manifold, there should be 3 exhaust sections and 2 hanger/support points. Each support assembly utilizes a thick rectangular rubber strap, about 5 inches in length, to hold about a third of the exhaust system. If one of those support straps is missing, an excessive amount of stress is placed upon the remaining parts of the support system (which includes the manifold bolts and manifold flange).
Asking just the manifold and the rear hanger to hold the entire system up will only create problems.
When I bought my S3, I discovered that one of the POs had replaced the cat in the downpipe the lazy man's way, by merely cutting the old cat out along with a few inches of pipe on both sides of it and welding a new catalytic converter in that place. Unfortunately, that hack job included the removal of the factory support bracket on the downpipe. The result was a downpipe with a crack near the manifold flange when I bought the car.
Magnaflow makes a very nice stainless downpipe/cat unit for our spiders that is an exact fit/replacement for the stock one. That's what I purchased and installed and I am very happy with it.
 

·
Registered
Joined
·
325 Posts
Discussion Starter #5
Pic of cat hanger assembly?

Has anyone a picture they could post of a correct cat hangar assembly for an S3? I find a real pic does a better job than the exploded shop manual pics.

Worked on my checklist of possible causes for my S3 sputtering and bucking today. When I got her started I couldn't help but hear a rattling sound coming from the vicinity of the cat. After about 20 miles and neighborhood and country road driving, she began to buck and sputter and the vicinity of the cat felt and smelled very hot.

I now think it safe to say that the cat (probably original) needs replaced. I've found a good deal on a Magnaflow 23511 that will bolt right on.

I've one question. my current cat has no hanger coming off of it. I do have the hangar bracket that attaches to the transmission, just nothing coming off the current cat.

I'd like to know what the correct assembly should look like when I hook up the new cat.

Thanks in advance-M5
 

·
Premium Member
Joined
·
1,454 Posts
A cat that is overheating could be a good cat working it's heart out trying to consume an excess of unburnt fuel... food for thought.
 

·
Premium Member
Joined
·
1,577 Posts
Has anyone a picture they could post of a correct cat hangar assembly for an S3? I find a real pic does a better job than the exploded shop manual pics.

Thanks in advance-M5
Hi Miami:

Here is a link to a post that has a few pictures of the rubber hanger straps that support the middle and rear exhaust sections:

http://www.alfabb.com/bb/forums/spider-1966-up/264193-replacing-center-rear-exhaust-87-spider.html#post4975457

If that link isn't enough, I've tossed in a couple more photos that might help.

The first picture below shows a Magnaflow downpipe/cat assembly. This unit connects between the manifold and the center silencer unit. Note the fork extending off the side of the pipe between the down tubes and the catalytic converter. That fork bolts to the bracket under the transmission.

The second photo shows a diagram of the entire exhaust system (of a Series 3 Spider). Sorry that it's so small. One of the rubber hangers connects to the middle silencer pipe unit, and the other rubber hanger strap supports the rear section, but the bracket welded on the rear pipe isn't clear in this diagram (it's on the side that isn't shown).

Hope this helps.
 

Attachments

·
Registered
Joined
·
325 Posts
Discussion Starter #8
You may have a point

A cat that is overheating could be a good cat working it's heart out trying to consume an excess of unburnt fuel... food for thought.
That very well may be. The pretty heavy rattling that I heard from the vicinity of the cat when I first got her started leads me to believe that she very well may be kaput.

You are correct in that I need to make sure that I've no issues ahead of the cat.

Thanks much-M5
 

·
Registered
Joined
·
325 Posts
Discussion Starter #9
Edward,

Thanks for the pics and the link. I experience pretty much what you did when I replaced my middle and rear sections. Those pics and steps came in super handy but still took me a good amount of time since I was a one man operation.

My main concern is for the section that attaches to transmission plate when I replace the cat. My current cat has no bar coming off it although I do have the plate attached to the transmission. I just want to make sure I do it correctly.

Thank you so much for the pics and direction-M5
 

·
Registered
Joined
·
30 Posts
Catalytic Support

In the exhaust system above, does anyone have a description or picture of where the support (#3 in the diagram) attaches? There is 3 holes in the support and I do not see where i can be bolted. I would assume that it would attach to the transmission mount cross bar but the 2 holes in the cross bar do not line up with the support.

I took the exhaust, heat shield and drive shaft out of my 91 spider to do work on each component at the end of last season and forgot to take a picture of this section.

I have the drive shaft in, and transmission mount cross bar in but don't know how to attach the catalytic support.

Thanks for any and all help.
 

·
Registered
Joined
·
325 Posts
Discussion Starter #11
I only had two on my transmission bracket. It did take a bit of cajoling to get them lined up properly but it can be done.

Can you post a pic of your 3 hole setup?
 

·
Registered
Joined
·
325 Posts
Discussion Starter #13
OK. I see now.

The three holes to the top will attach to the transmission.

The two on the bottom right connect to the catalytic converter.

If it helps, the way you have it oriented in the pic is the way you would see it if you were looking under the front of the car. The "face" of the pic is facing front and the bottom right is pointing to the driver side (US) of the car.

Hope this helps-M5
 

·
Premium Member
Joined
·
1,577 Posts
And here are a few more photos of that bracket (pardon the massive quantities of rust inhibitor).

As Lucas notes, it attaches on top of the 3 nuts that secure the rear tower/cover to the bottom 3 gearbox studs (and it is located just in front of the tranny mount bush and crossmember).
 

Attachments

·
Registered
Joined
·
30 Posts
Catalytic Support

In the exhaust system above, does anyone have a description or picture of where the support (#3 in the diagram) attaches? There is 3 holes in the support and I do not see where i can be bolted. I would assume that it would attach to the transmission mount cross bar but the 2 holes in the cross bar do not line up with the support.

I took the exhaust, heat shield and drive shaft out of my 91 spider to do work on each component at the end of last season and forgot to take a picture of this section.

I have the drive shaft in, and transmission mount cross bar in but don't know how to attach the catalytic support.

Thanks for any and all help.
 

·
Registered
Joined
·
325 Posts
Discussion Starter #17
From the pics you provided Lucas I think you have it placed properly on the transmission.

Be advised you will want to keep all the other connections on both ends of the CAT as loose as possible. The support isn't just going to line up DAP on the first try. You will want to keep both ends just barely connected and then move/cajole the support bolts in to the CAT. At that point you can start tightening little by little to assure that you have a good fit and a good seal.

Also be advised that if your motor and/or trans mounts are going/shot that will add even more challenges to proper fitment.

You will also find it helpful to loosen your other exhaust brackets to allow a bit of movement in aligning everything. Just make sure you tighten everything up a little bit at a time to make sure everything settles right.

As far as pics, I've found the most helpful to be the ones provided by Norseman50. My manual does not have the highest quality diagrams.

Hope this helps-M5
 

·
Registered
Joined
·
30 Posts
I know this might be the wrong area to ask the question but while we are talking about the Cat, can I use standard pipe insulation (I believe fiberglass) in place of the asbestos between the aluminum heat shield and the underside of the car? I plan on using a 1/4 inch space to keep some air in between the heat shield and the underside of the car as well.

Will it get too hot for the fiberglass?
 
1 - 18 of 18 Posts
Top