Report: C32 Secondary Cat (ONLY) Delete
One user had said that this was the method to achieve the best sound using the factory exhaust system. After cutting them off and driving around I am extremely happy with the result. Unlike the videos I have seen/heard of the resonator delete, removing just the secondary cats has not added any raspiness or change in tone and instead made the volume of the exhaust better. There is a deep sound at idle and driving around town but an aggressive throaty growl when really getting on it. In some RPM ranges it almost sounds similar to stock but it definitely sounds better on the outside.
In one sentence, this modification to the exhaust has made the car sound like it should have from the factory but still like a Mercedes Benz AMG and not a boy-racer. I am enjoying a new found love for my car.
Best,
Ken
Last edited by Ken311; Sep 24, 2011 at 08:09 PM.
In addition there is a significant change in tone below 3500 rpm with some rapiness around 2500-3000 rpm. It also has produced a significant drone in that same rpm range while on the freeway that is present even on flat roads with cruise control. The high rpm growl that starts at 4000+ sounds exactly the same in tone, just louder. Low end torque also feels like it has taken a hit but the top end feels the same.
I can now recommend with 100% certainty that the resonator should be kept when modifying the factory exhaust system if not only for sound, but for performance as well. (my car is stock) The secondary cat delete is a good option for more sound and if that is not enough it is best to start looking at new mufflers.
-Ken
PS: I will get a video of the sound change before I have the resonator put back on.
Last edited by Ken311; Nov 23, 2011 at 03:44 PM.
In addition there is a significant change in tone below 3500 rpm with some rapiness around 2500-3000 rpm. It also has produced a significant drone in that same rpm range while on the freeway that is present even on flat roads with cruise control. The high rpm growl that starts at 4000+ sounds exactly the same in tone, just louder. Low end torque also feels like it has taken a hit but the top end feels the same.
I can now recommend with 100% certainty that the resonator should be kept when modifying the factory exhaust system if not only for sound, but for performance as well. (my car is stock) The secondary cat delete is a good option for more sound and if that is not enough it is best to start looking at new mufflers.
-Ken
PS: I will get a video of the sound change before I have the resonator put back on.
Here is a sound clip for you to be the judge. This was done that day I got it and only at like half throttle around 3k RPM.
http://www.youtube.com/watch?v=0cgEnq7jHUM
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Here is a sound clip for you to be the judge. This was done that day I got it and only at like half throttle around 3k RPM.
http://www.youtube.com/watch?v=0cgEnq7jHUM
To anyone looking to do this, I would recommend cutting the secondaries first then driving around for a few days before deciding to go ahead with the resonator as well. It won't cost you any extra other than another trip to the muffler shop.
go in and ask the muffler techs that you want to have the two 'bottle resonators' removed. when they lift the car they'll see they are actually cats and not resonators. in case they tell you they aren't resonators, tell them you want them removed at the advice of a friend with the same car (or similar story). if the techs are cool they usually will take them off if you pay cash.
removing the real resonator is legal and anyone will do it.
good luck,
Ken


Here is what the setup sounds like in normal driving. The sound is not something that fits the character of the car in my opinion. My camera has HQ audio recording so this is a very accurate representation of the sound.
http://www.youtube.com/watch?v=SxreEiuP33U
Once I put the resonator back on I will get more vids of the secondary cat delete by itself.
Cheers,
Ken
Last edited by Ken311; Nov 27, 2011 at 09:40 PM.
go in and ask the muffler techs that you want to have the two 'bottle resonators' removed. when they lift the car they'll see they are actually cats and not resonators. in case they tell you they aren't resonators, tell them you want them removed at the advice of a friend with the same car (or similar story). if the techs are cool they usually will take them off if you pay cash.
removing the real resonator is legal and anyone will do it.
good luck,
Ken
Funny you mention the stainless piping...the shop I ended up going with wanted to use aluminized steel and i fought them back and forth on it. In the end I told them if they would not use stainless I would go somewhere else and it was at that point the manager came out carrying some stainless pipes from the back.
I'm not sure why they are hesitant but most shops should have stainless.
Good luck,
Ken
Before I go ahead and put the stock resonator back in, I have decided to try a magnaflow glass pack in lieu of the resonator to see if that adds any volume while hopefully killing some of the raspiness and drone.
I should be able to get this done tomorrow as the part just arrived at my house this afternoon. Keep an eye out for yet another sound clip and review.
-Ken
Also, I don't have any rasp throughout my RPM range at all.










