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Secondary Cat Delete-great mod!

24K views 77 replies 25 participants last post by  iLLGT2 
#1 ·
I had my secondary cats removed by Evosport a couple weeks ago and really like the results. There is better throttle response now especially off the line. I remember when I first drove the M6 I thought I left the parking brake on or left it in nuetral since it was so sluggishly delayed starting out. Now it is more instant. I do not know how much hp or torque gain if any, but the car feels quicker. Sorry for the seat of pants only measurment.

Secondly I loved the sound of the Eisenmann race exhaust, but would have liked more low end growl and there was some serious bass resonance around 3400 rpms in the cabin that was a little too loud for most passengers. Of course it only happened at or around that rpm. Now with the 2ndary cats out I have the low end bassey growl and the resonance is gone!

This is a video of the exhaust sound after 2ndary cats out.
http://www.youtube.com/watch?v=Qlrjox2am9I


This is a video comparing the before and after taking cats out.
http://www.youtube.com/watch?v=Zv3L5qR0NoI

Enjoy I hope this is helpful.:M5thumbs:
 
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#2 ·
????????????????????????????????????

Great. That tiny delay can be bothersome.

What was the cost?

Could there be any problems with warranty?

Where can it be done?

Any performance numbers?

TIA
 
#3 ·
It takes between 2 to 3 hours of labor and materials is the cost of stainless steel piping to replace the cat. Cannot comment conclusively on the warranty but it is such a cheap mod that if needed they simply be put back in.
 
#5 ·
My exterior mods include Vorsteiner Hood and painted grills. Wheels coming soon...



Land vehicle Vehicle Luxury vehicle Car Personal luxury car


Land vehicle Vehicle Car Luxury vehicle Personal luxury car
 
#8 ·
That sounds godly.... Loving the sound of your car! Wish I had one!
 
#10 ·
One question: In germany we have the exhaust fumes checked every 2 years. Don't you get into trouble if you have your secondary cat removed? You must have higher emissions in your exhaust fumes now.

But without the cat, the cars sound a lot of more aggressive. Nice job!
 
#11 ·
DaveM said:
Wow- I really like the sound! Very professional job on the video too.

I don't have my cab yet, but do you know if the Sec. cats had to be cut out, or are they bolted in for a quick removal?
Thanks in advance
Thanks for the props. They have to be cut.
 
#12 ·
Darek said:
One question: In germany we have the exhaust fumes checked every 2 years. Don't you get into trouble if you have your secondary cat removed? You must have higher emissions in your exhaust fumes now.

But without the cat, the cars sound a lot of more aggressive. Nice job!
Thanks for the compliment. Here is my smog check rules in California:

"Beginning January 1, 2005, vehicles 4 or less model-years old are exempt from the Smog Check inspection requirement upon change of ownership and transfer of title transactions with DMV. In 2006, this exemption includes model-years 2003, 2004, 2005 and 2006."

So until I sell it I do not need a smog check.:applause:​
 
#15 ·
Darek said:
You have better laws than we here in germany :mad:. In germany your mod wouldn't be possible, because the car would loose its permission and you get into real trouble if the police catches you ouich.

Do you have any performance numbers?
We have better laws in some regards, but you still have the Autobahn.:M5thumbs: Sorry no performance numbers. It was not a significant enough mod to warrant a dyno run.
 
#17 ·
lawrencew83 said:
nice!! it sounds so aggresive!!

btw is secondary cat delete = replacing stock with eisenmann section 2/supersprint x pipe?
It is not the same as the x-pipe or section 2, these replace the reasonator section not the secondary cat. Using the x-pipe doesn't give much, if any at all, performance gain, but will give a huge sound level increase although it tends to sounds clacky if you will.
 
#19 ·
just removed the secondary cats, all i can say is that u've got to here this in person, absolutely amazing. the sound doesn't drone very much in the car at all, but from the back to bystanders its sounds stunning. bmw should've made the car sound like this from the factory.
 
#45 ·
#21 ·
no check engine light on mine.
 
#23 ·
Can you post pictures from the bottom of your M6 showing the modification?
 
#24 ·
Interesting that Eisenmann makes a Section 1 for the M5 but not the M6. Or does the same Section 1 fit both?
 
#26 ·
Kinda Makes me want to get a V-10! I said KINDA:hihihi:

Looks Great and Sounds GREAT:thumbsup:
Look forward to seeing you next week and hearing it in person.
g
 
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