Cat removal

[kevinbuenoo]

My pipe broke off the flange on my passenger side cat. I need help on how to lower the tranny. A lot of people have said that they let the tranny sag and wiggle it out. Would I need to support the engine from above? If so, why?
I’m thinking of just supporting the tranny with a jack and letting it sag since I wouldn’t be touching any of the motor mounts.

Can someone guide me through this process with any of their experience?

Thanks in advance


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[kevinbuenoo]

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[whiped]

I've done it twice now. Once to gut the cats and once to replace them with test pipes after blowing the flange off.

Assuming you don't care about the cats you can cut them out and it will save you from dropping the subframe.

Only the passenger side is super tight, drivers side can come out without cutting.

Anyway here is a quick run down:
Remove the Exhaust and Downpipes
Sag the trans by undoing the bolt that hold on the support. (put a jack under it before loosening the bolts then slowly lower it until you have enough space.
Remove the secondary O2 sensors
Remove the bolt from the support
Remove the 3 bolts holding the cats to the manifold
Cut the bottom of the cats off
Wiggle the cats out



If you don't want to cut them you will need to support the engine from above and drop the subframe.

[Chibo]

I've done it twice now. Once to gut the cats and once to replace them with test pipes after blowing the flange off.

Assuming you don't care about the cats you can cut them out and it will save you from dropping the subframe.

Only the passenger side is super tight, drivers side can come out without cutting.

Anyway here is a quick run down:
Remove the Exhaust and Downpipes
Sag the trans by undoing the bolt that hold on the support. (put a jack under it before loosening the bolts then slowly lower it until you have enough space.
Remove the secondary O2 sensors
Remove the bolt from the support
Remove the 3 bolts holding the cats to the manifold
Cut the bottom of the cats off
Wiggle the cats out



If you don't want to cut them you will need to support the engine from above and drop the subframe.

How many hours of labor is this once the exhaust and downpipes are removed?


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[whiped]

We did it in about 4 hours both times. (Our time, shop time like like 8 hours?)

The second time we also installed a few other parts and ate lunch.

It's a pain in the ass to do

[Chibo]

Thanks! Will get my installer to try this method (I’m dsg).

[denako]

I've done it twice now. Once to gut the cats and once to replace them with test pipes after blowing the flange off.

Geoff, if one doesn't want to go the test pipe route, what do you recommend for gutted cats to avoid the flanges breaking off over time? Re-weld the support around them before throwing them back in?

[whiped]

Geoff, if one doesn't want to go the test pipe route, what do you recommend for gutted cats to avoid the flanges breaking off over time? Re-weld the support around them before throwing them back in?

Yeah if you reinforce the welds you might be fine.

Honestly, I'd just do test pipes. Even if they are the cheap chinesium ones.

[denako]

Yeah if you reinforce the welds you might be fine.

Honestly, I'd just do test pipes. Even if they are the cheap chinesium ones.

I wanted to keep the gutted cats more so for the feedback I've heard with sound. Supposedly gutted cats have a lot less rasp and dB level then test pipes? Maybe you can chime in on this since you've had both at one point.

[whiped]

Gutted cats were for sure quieter.

Test pipes are louder, deeper and in my case drone less.

If you are only worried about sound add mufflers downstream to reduce it.

[Chibo]

By the way how much room is there to work with under this method? Looks like installing test pipes is fine but is there enough room for hfc’s which will be smaller than oem cats?

If dropping the subframe, what are the high level instructions from beginning to finish? Will install this Monday, thanks!

[daytonas4]

By the way how much room is there to work with under this method? Looks like installing test pipes is fine but is there enough room for hfc’s which will be smaller than oem cats?

If dropping the subframe, what are the high level instructions from beginning to finish? Will install this Monday, thanks!

i just did this this past weekend on my dsg car , its really easy , i did not drop the subframe either , just drop the whole exhaust , remove the x brace , undo the 02 sensors (from the top) remove the trans mount / remove the 2 bolts from the drive shaft bearing / let trans hang down , pull out the cats , drivers side is easy , pass side i had to cut the bottom cat flange off and thats it ,, took about 4 hours ,

[TruS4]

Anyway direction on install of spacers once test pipes already installed?

[uponone nogaro]

Was there added power felt once cats where gutted or test pipes installed

[finnicky7]

We did it in about 4 hours both times. (Our time, shop time like like 8 hours?)

The second time we also installed a few other parts and ate lunch.

It's a pain in the ass to do

Bring this one back from dead, but did you use a lift? Sawsall for flange cut?

[kashanova]

I added Eurocode test pipes, resonated DPs and the AWE touring exhaust and I have zero drone. It's a little on the loud side but at least there's no drone.

[EIAlfonso]

Bring this one back from dead, but did you use a lift? Sawsall for flange cut?

I'm in the middle of doing this, bought a $30 angle grinder w metal disc packs at Harbor Freight to cut

[chaos2984]

how are you guys dealing with cel that comes on for the CAT's are you just using o2 spacers? if so which ones?

[03redgti]

how are you guys dealing with cel that comes on for the CAT's are you just using o2 spacers? if so which ones?

Vibrant straight spacers on amazon are they way to go. The j spacers sometimes get cel's sometimes don't but the vibrant straight never do.

[KLX]

I added Eurocode test pipes, resonated DPs and the AWE touring exhaust and I have zero drone. It's a little on the loud side but at least there's no drone.

I had JHM test pipes on the same touring exhaust, and the drone and smell was too much, how is the exhaust smell on your setup...??

[kashanova]

I had JHM test pipes on the same touring exhaust, and the drone and smell was too much, how is the exhaust smell on your setup...??

It's been cold so I haven't had the windows down at all. I haven't really noticed anything smell wise but I've only had it on for three or four days.

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[KLX]

Copy that, down south it's 60-70 degrees, so most of my travels I have the windows cracked, but at stop lights it's was noticed..

[kashanova]

Copy that, down south it's 60-70 degrees, so most of my travels I have the windows cracked, but at stop lights it's was noticed..

I'm trying to find a way to add the cats in the downpipes, I'll let you know how it goes.

[EAFLO88]

Does anyone know of a method to apply the spacers for the o2 sensors while the test pipes are on?

[maty360414]

Does anyone know of a method to apply the spacers for the o2 sensors while the test pipes are on?

from the top 30 minutes

[ModItNow]

from the top 30 minutes

How the heck do you squeeze in that tight space? Been rollin with a CEL for like 2 years lol

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[Big_Joe]

I wanna know how the hell you unbolt the exhaust, I had to lower the entire thing when I removed my engine, the back side nuts that are against the transmission are a nightmare to access from the silencers and the cats

[EAFLO88]

from the top 30 minutes

Really? Geez, I’d pay to have someone show me a quick video getting to them from up top!

[maty360414]

Really? Geez, I’d pay to have someone show me a quick video getting to them from up top!

I have ninja hands

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[raudiace4]

I had JHM test pipes on the same touring exhaust, and the drone and smell was too much, how is the exhaust smell on your setup...??

I had O34's test pipes to stock DPs, and Awe touring on my first S4. This was in 2013 and there were very limited options when your cats died, the drone was so bad that I hated driving the car. It was unbelievably loud, just ruined the car for me. I'd do anything to avoid test pipes on these cars.

YMMV. Also heard if you wrap the Test pipes and down pipes in heat wrap it dramatically reduces drone. Some of you guys might want to try that, I wonder if ceramic coating would help too.

[luciddream]

Can I resurrect again! Quick post as I keep searching for my answer.
Just got my xs exhaust with 3" dp and test pipes going to 2.5" true dual. It came with one o2 sensor extension but I though you need 2 at least.
Am I right? Do I need to install 2 so I don't get a cel? Or all 4? Or is 1 enough and where is the best place if 1 is enough?
Thanks20190823_164519.jpeg

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[SSSSS5]

from the top 30 minutes

I'll assume you have a 6 spd. I have the auto ZF trans and tried this method. It definitely helped with o2 removal and visibility, but no way I could pull them from above, not enough room in my 2013 s5. I was able to pull my cats whole, from below after lowering the trans, dropping my subframe, and ratchet strapping the trans over. What a chore. Had to pull the drivers side one through the wheel well.

[maty360414]

I'll assume you have a 6 spd. I have the auto ZF trans and tried this method. It definitely helped with o2 removal and visibility, but no way I could pull them from above, not enough room in my 2013 s5. I was able to pull my cats whole, from below after lowering the trans, dropping my subframe, and ratchet strapping the trans over. What a chore. Had to pull the drivers side one through the wheel well.

I have a DSG, I have thin hands so I got it done all from the top

[SSSSS5]

I have a DSG, I have thin hands so I got it done all from the top

WOW! didnt drop the subframe or trans at all? Looked impossible to me without brute force and a 3lb sledge from above.

[maty360414]

WOW! didnt drop the subframe or trans at all? Looked impossible to me without brute force and a 3lb sledge from above.

Wait lol I was talking about the O2 sensor not the whole cats sorry for the confusion

[SSSSS5]

Wait lol I was talking about the O2 sensor not the whole cats sorry for the confusion

Ohhhh yeah, that I can agree with you on! Made the o2's a cakewalk

[Only_a_V6lol]

What setup do you guys use for getting the nuts loose from the manifold so the cats can come off? This crap is kicking my ass, and I’m kinda just needing to pick some brains to get a handle on the situation

[BlackJon]

I think I may need to figure out what I want to do with my car, I went dual pulley with IE Tuning stage 2 crackles but I think its starting to smell just a little. What are my options?? In case they do go?? Thanks guys

Drive It Like You Stole It

[JACKAL]

I think I may need to figure out what I want to do with my car, I went dual pulley with IE Tuning stage 2 crackles but I think its starting to smell just a little. What are my options?? In case they do go?? Thanks guys

Drive It Like You Stole It

You can gut your cats or put on test pipes. Gutted cats tend to have a little less drone and rasp than test pipes. If you go this route, you should reinforce the flange welds as they are prone to cracking. You can also keep driving and monitoring for signs of the cats either blowing out (in which case you luck out and don't need to bother with a challenging removal and re-install) or plugging. Plugging obviously has the potential for engine damage though, so you are running a risk.

[luxmatic]

Cats on my car are also showing signs of failing (silver dust in tailpipes, sounds deeper than it usually does, and feels slower), towing the car to a buddy's place to gut the cats tomorrow morning. Parked the car at home as soon as I noticed as I don't want to risk damage to motor if it is a clog.

Fingers crossed it'll go smoothly, will report back with results