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Discussion Starter #1
After doing extensive research on here, I decided to have the secondary cats removed.

Based on the picture, is it "A" or "B"?

Thanks in advance! :cheers:
 

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Discussion Starter #3

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DinanS2+ e60m5 6MT, s38b38 e28m5 TT/ST3, e30 TT/ST4
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Discussion Starter #7
No. Post O2 sensors are ahead of the secondary cats.
This was one of the main reasons for deciding on having the secondary cats removed.

Picking up a few HP and a bit more sound won't hurt either :M5launch:
(although I already did the muffler delete).

I should have it done later in the week; will come back and post an update :cheers:
 

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I actually removed both A and B and running Dinan straight pipes in place of this. I will never go back to our stock setup not to mention the weight reduction. If you're wanting more umph you might consider removing A and B together.

Dan
 
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Isn't B the xpipe? Resonators are further back closer to the section 3 I thought.


Sent from AutoGuide.com Free App
 

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Details are in my sig, but this is my set up.
 

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Discussion Starter #11
I actually removed both A and B and running Dinan straight pipes in place of this. I will never go back to our stock setup not to mention the weight reduction. If you're wanting more umph you might consider removing A and B together.

Dan
Since I already deleted the mufflers, won't the sound be extremely louder without the resonator? :confused3:dunno:

I was planning on keeping the resonator and just deleting the secondary cats.
 

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DinanS2+ e60m5 6MT, s38b38 e28m5 TT/ST3, e30 TT/ST4
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Since I already deleted the mufflers, won't the sound be extremely louder without the resonator? :confused3:dunno:

I was planning on keeping the resonator and just deleting the secondary cats.


The stock resonator/h-pipe/x-pipe is not the best design; I would replace Section 2 with an x-pipe (your "B").

It's a slippery slope, huh?

You can run a resonator in place of the secondary cats, Section 1 (your "A"). I wanted to be loud, but not "pull me over loud" living at the Beach. I'm running a 3.5" Dinan resonator. A 4.0" resonator, would be even quieter. For Dinan, the larger the diameter the resonator, the quieter the sound.

The added benefit, at least for me, to running a small resonator in place of the secondary cats -- on a quick visual inspection from CHP, my resonators look like cats. Unless you're in the know, the resonators can look like cats.
 

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The stock resonator/h-pipe/x-pipe is not the best design; I would replace Section 2 with an x-pipe (your "B").

It's a slippery slope, huh?

You can run a resonator in place of the secondary cats, Section 1 (your "A"). I wanted to be loud, but not "pull me over loud" living at the Beach. I'm running a 3.5" Dinan resonator. A 4.0" resonator, would be even quieter. For Dinan, the larger the diameter the resonator, the quieter the sound.

The added benefit, at least for me, to running a small resonator in place of the secondary cats -- on a quick visual inspection from CHP, my resonators look like cats. Unless you're in the know, the resonators can look like cats.
I have seen reports from others regarding torque lost from deleting the stock resonators and not replacing it some a x pipe of some sort. Full exhaust systems are out of the question since those include all the sections, for example RPi includes their hybrid x-pipe design with their GT and GTS setups.

What do you think Woody?
 

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I'm running the identical set up as Woody's. In fact, it was because of his set up that I went home ranting and raving to the wife over the awesome sound that she got me the Dinan middle racing exhaust for Xmas which has the secondary cats removed. For more tq (if there would happen to be any loss) you can go with headers and delete your primary cats as well. :biggrinbounce:
 
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I have seen reports from others regarding torque lost from deleting the stock resonators and not replacing it some a x pipe of some sort. Full exhaust systems are out of the question since those include all the sections, for example RPi includes their hybrid x-pipe design with their GT and GTS setups.

What do you think Woody?
I recall something like that -- on the lower rev range, which is the reason no one runs straight pipes all the way out the back.

Short of running open headers, and a dump valve for the drag strip, I think you want some sort of x-pipe. I'm sure others, that are better informed, will chime in.
 

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Remove your primary Cats , that is where you get The power ! Secoundary Cats i taken out too but on a dyno only 5 whp so i deciced to put in back
 

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Discussion Starter #18
Thanks for all the advice guys! Very helpful!

For now, I plan on deleting just the secondary cats (and keeping the resonator).

Will be back to post an update.

Now, just have to find a muffler shop that will remove the cats ("under the table").


 

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Thanks for all the advice guys! Very helpful!

For now, I plan on deleting just the secondary cats (and keeping the resonator).

Will be back to post an update.

Now, just have to find a muffler shop that will remove the cats ("under the table").


Tell them you're removing your resonator...you can't see through the cats on the stock design. :lightbulb:
 

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Discussion Starter #20
Tell them you're removing your resonator...you can't see through the cats on the stock design. :lightbulb:
Hahaha.. "M5 minds think alike" lol...
 
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