# Resonators, Cats and the TTS



## TheStarkFactor (Sep 5, 2013)

Hello.

I had asked this question on the TT facebook group, but didn't get a clear answer, so hoping someone here might be able to clear this up for me.

I have been led to believe that there are two catalytic converters and two resonators on the Audi TTS.

The primary cat, inaccessible from underneath, located near the engine and the secondary cat being located in the middle of the exhaust.

I have recently had a single resonator delete, the exhaust garage I took it to removed the oval resonator, pictured first in the attached photo.

A few folk have since claimed this is in fact the secondary cat, while others claimed that all three are resonators and finally some others have claimed the secondary cat is the middle item.

The exhaust garage said the middle item was the secondary cat, the first and third items are resonators.

Can anyone clear this up?


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## -:[KM]:- (May 16, 2010)

Is that a pic of _your_ car?
I've an s-line Quattro and I didn't have the first box on the left. I was under the impression that it was a spec for noise sensitive regions (guessing- California??)
I _have_ removed the next two and can confirm these aren't catalytic converters. Just resonators that should never have been there in my opinion.


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## TheStarkFactor (Sep 5, 2013)

Thanks for the reply.

No, this isn't the underneath of my TTS, but I can confirm it matched the underneath of my TTS up until the exhaust garage removed the oval, what I was told, resonator.

So I am a little worried that the garage have removed a cat instead of a resonator.


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## -:[KM]:- (May 16, 2010)

Are you sure it's not the first of the ones I removed? Do you have it?
The reason I say this is because the first box isn't very *oval*...








You can see the cat there too. That first box looks more like a mini silencer due to its build IMO. Thin walled steel rather than welded and capped construction.

Come on... get them all off!!


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## -:[KM]:- (May 16, 2010)

Also, "the first oval" is subjective. They could have been walking from the back to the front of the car. Then it is indeed very oval.


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## TheStarkFactor (Sep 5, 2013)

Hi Folks.

I was near the car when it was removed.

The oval part, circled in red was removed.

Thanks


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## TheStarkFactor (Sep 5, 2013)

Wee bump to put my mind at rest that we've not removed the secondary cat.


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## ianle (Apr 2, 2015)

I have had a Resonator delete and it was the box on the right and not the one you have circled.

You can see picture here

https://store.034motorsport.com/res-x-resonator-delete-8s-audi-tt-s-quattro.html


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## StuD (Jan 7, 2021)

I also had the resonator removed and it was the oval box on the right. The last one before the rear muffler. The garage said I could take all three out but I declined.
I am now considering a turbo back exhaust including down pipe up until the rear muffler so I can still use the OEM valves.
Has anyone had experience of this?


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## Gnasher (Oct 21, 2020)

What model year is the car? If it's fairly new, this could be the dreaded GPF


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## Emanuel29 (Oct 28, 2019)

Hi. As I am struggling to understand the same thing I can tell you that my garage has removed the other 2 parts which they said are resonators and I have left the one you circled in red which according to them is a cat. not a res...


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