All right. I haven't done it yet. But, I'm ready to change out my catalytic converter. I've got some time next week. So, anyone have any tips for me? Maybe someone has done this recently and can tell me the easy way to do it. I've looked around briefly and I see cats for about $179 at Tweeks. For around $129, I can get the local muffler shop to install a generic/universal cat. But, I'm hesitant because it looks nothing like the OEM cat. The cat in Tweeks looks like an OEM. But, the price leads me to believe that it's not.

This weekend, I'm going to remove the old, original cat. Is the original cat welded in place? Or, is it just clamped?

I'll be using a lift to make the job easier. Do I need any tools other than my basic metric wrenches and cooler?

Also, while under the car, I'm going to re-paint the muffler and polish its tip. Are there any other items that I should check, replace, work-on while I have the muffler and cat down?

Appreciate the advice. Don't want to re-invent the wheel.

Terry
'84 Guards Red
Original Owner

 

My origional one is welded onto the downpipe. I too will be replacing it with a 100cell race cat, and use the old hollowed out one as a test pipe. Once tuned, the new one goes on it. My problem is that I cannot find a set of flanges that match the stock 4 bolt ones on it. (Re-worded.. a set for less than $100!)

 

A real OE cat runs closer to $500

A popular aftermarket alternative, and similar to the OE cat, is from Bosal.

I replaced mine with a Catco cat from Summit Racing for ~$60. Chances are, the cat your shop will install is from Catco.

Good Luck!

 

Jon and I gutted my cat last weekend. It sounds like crap now. It's like there is a Folgers can in the middle of my exhaust. I will be replacing it with just a straight pipe..no cat.

 

We used to have two but now we only have one. The little **** used to crap on the floor in the basement. Does that qualify as a change??

 

I don't know the laws in your state but here in South Carolina, we have no vehicle inspection. I had my local shop remove my cat. It made the car sound a little throatier and it seemed to add a little power also. The biggest think I noticed was the increased fuel mileage!
I would recommend removing it all together but I know some states dont allow it and also I have read posts that the removal of a cat has negative effects on you car in the long run.
Just my opinions.

Steve

 

Curious on opinions of race cat (3") vs. test pipe (3") HP/full boost RPM wise..

thanks,

Adrial

 

Everyone so far,
Thanks for the advice / info. I do live in California. So, the catalytic converter is going to get me through smog. I can't leave it off.

Skip,
Can I install that Catco unit myself? Or is welding involved?

 

My kids want a dog, so they are always hoping someone will remove our cats. No luck yet, and I'm firm. No dogs until the cats are in heaven.

 

According to the PO, the 951 was in the shop having some work done and they were thinking of changing out the cat. As it just so happened, a new 911 was also in the shop having it's cat removed and a total new race system installed. Since the two cars were on the rack next to each other a quick deal was made and now my 951 has a 911 Cat. Don't know if the story is true or not, but I'm passing the smog tests with flying colors!

 

[quote]Originally posted by Terry Jamison:
<strong>Skip,
Can I install that Catco unit myself? Or is welding involved?</strong><hr></blockquote>

I guess... would be better if it was welded on - but, if you choose the right size, and there's enough pipe to attach too front and rear, it certainly would work with clamps only. FYI, the Catco cats are the *short-standard* oval shape vice the *long-round* of the OE type... there may not be enough pipe to bridge the gap.

Skip

 

I've just changed the cat on my S2. You don't say "why" you need to change it.

a new cat from OEM is closer to £1300 and that is "just" for the cat unit.

The Cat unit is welded to the downpipe.

I went down the route of replacing mine (for different reasons) with one from a breaker, paid £80 for mine. The cat already came with the downpipe so in thory it was a lot easier to reomve.

except 1 of the 3 bolts were siezed, so we ended up dropping the whole system dragging it out and grinding off the bolt, still re-fitting was easy.

make sure you get new bolts/nuts, 2 gaskets and the rear washer (thick thing can't remember what its officially called) it makes a gas tight seal between the cat and the middle box.

holla back

 

I use to have a white and grey tabby..................now I have a white and brown tabby. <img src="graemlins/xyxwave.gif" border="0" alt="[bigbye]" /> <img src="graemlins/c.gif" border="0" alt="[ouch]" /> <img src="graemlins/bigok.gif" border="0" alt="[thumbsup]" />

 

<a href="http://communities.msn.ca/peckj76/shoebox.msnw?action=ShowPhoto&PhotoID=2" target="_blank">web page</a>

 

just to add onto what skip says, get the three way cats because the two way dont get the nox gas down enough to pass, something to do with how the cat converts it on the the second set of elements.

i had replace mine with the catco two ways once and the nox doubled then went to the sound design (i think thats what they are called) three way cats and the nox went down to normal.