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Has anyone... [Deleted secondary cat stock]

17K views 55 replies 27 participants last post by  Gustav 
#1 ·
I know that people have taken out the secondary cat when they put on their Eisenmann exhaust.

My question is, has anyone taken off the cat on stock exhaust? If so, how does it sound?


thnx!
 
#41 ·
Rasp Question - Secondary Cats Removed

Hi All-

After removing the secondary cats and the stock x-pipe and replacing with straight pipes and an aftermarket x-pipe, the exhaust is a bit louder but the rasp is so loud that it seems to shriek at high RPMs, especially if you tip into the throttle quickly.

My question: is there any way to get rid of this rasp? Do I have to install a set of resonators in place of the straight pipes? Or, do you think replacing the stock rear section with a set of aftermarket (thinking Tubi, Dinan, or even Magnaflow) rear mufflers take care of this rasp?

I am looking to make a bit more power if possible but also to round out the exhaust sound for something deeper in tone.

Thanks in advance for all of your help.

-Mike
 
#42 ·
I deleted my secondary cats today on a completely stock exhaust system. (The secondary cat delete is the only thing I’ve done to the exhaust) While I do definitely feel a gain in power, I can’t stand the raspy sound. The overall tone is only a little bit louder then stock. But it definitely has a much raspier tone to it. What can I do to remove the raspy tone? Get mufflers? Xpipe? Xpipe with mufflers? Or just put the secondary cats back on?<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" /><o:p></o:p>
 
#43 ·
No Secondary Cats = Rasp?

I think that's the key. With those spiral wound cats removed, the raspiness from the V-10's exhaust pulses come through unfiltered. I've heard this is inherent due to the header design and the only way to deal with it is to either install different length aftermarket headers or something in the way to muffle the rasp.

I'm in the same boat as you. I don't like the rasp at all but at the same time, I don't want to put resonators in place of the cats I've already cut out just to get rid of it. It's like spending 2x the money to get a net zero gain in performance.

The rasp at high RPMs is horrible, it makes the car sound like a Honda D16 or weed whacker at full throttle. Embarrassing.

If anyone knows that changing out the rear mufflers can make a difference, please reply.

Any help with the cure of the rasp will be appreciated!!! hiha
 
#47 ·
Hi Chrispy, thanks a lot for the diagrams. I didn't have them before, just actual pics of the sections. Essentially, I've got the entire catalytic converter/center muffler section cut out.

extassy, when you refer to section 1- losing the 40 lb/ft of torque, which section of the system is that? Is that the x-pipe?

Thanks!
From my understanding taking out the secondary cats (the section you've taken out) alledegly loses the torque, not the x-pipe...
 
#53 · (Edited)
Thank you so much bro!

My setup will be as follows:

Eisenmann Sport ovals
SS Xpipe
Stock cats
Evosport Headers

Now the real question... which ECU software to go for?? I wana reliable company that does Euro spec M5's! ( And gets rid of the Check Engine Light which I know I'm gonna get )
 
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