ATKM5

I already have the resonator removed, now I want to remove my secondary cats for more sound. Anybody did this before?

newguycls55

I've try to do this many times, but everyone suggested that not to do it because you will need an x-pipe and the space is tight right there, also the top of the secondary cats piping is oval not round.... I been lazy, but I am going to give straight pipe a try, remove the muffler and go straight all the way. To my understanding. Supercharged car should be pretty quite even with straight pipe, unlike the all motor car

cpais

The shop I go to has a CLS55 there right now that they are doing and they are planning on removing the cats and building a custom piece to go from the Kleemmann headers to the rear section of the exhaust. This car is heading to Dubai so catalytic conveters are not so important to this customer. I will try and stop by later tonight and take some pictures of it while it is still on the lift. I will try and post them sometime tomorrow for you.

CLK Masters

i've done this to my car.

however i live down here in forida where currently there are no emissions testing, but there is serous talk of instituting testing. so....

i droped the section with the secondary cats out of my car, took a rotary grinder and made a "flap in the tops of the cats, i then pealed open the flap and removed the filling of the cats, folded the flap back down and re welded the flap, so even the dealer has no clue that although the sencondary cats are there they are hollow.

cpais

Sorry it took me a couple of days to post this. I went down to RPM and took some photos that night but the exhaust was not completely welded yet so I was planning to get back there but I never got the chance. Here are the pics of the exhaust with the cats removed all mocked up in the car. You will see that it has an X-pipe, it measures 2 3/4" to conform with the factory exhaust and the Kleemmann headers. They made it using 304 stainless steel.

I am sure you will enjoy the photos. I have seen some pictures posted on here from some other peoples exhaust work and I even told them that I would have been embarrassed to post that kind of work on the internet.

newguycls55

did you get a chance to hear how it sound?

cpais

It was weird because at first it was obnoxiously loud but after a about a minute it quieted right down from the EGR. Once the EGR did its thing it sounded awesome. Very quiet at idle and it sounded very healthy when it revved and it was not loud at all. When the EGR was open it was very raspy sounding but once it was closed it sounded perfect.

newguycls55

Forgive me for not knowing what EGR stands for? can you explain. also I been asking around and wanted to know if is true that removing secondary cats on our supercharged 55 model will increase power by 20hp or so?
where is the RPM show located at?

cpais

RPM is in NY and EGR stands for exhaust gas recirculation.

newguycls55

do anyone know truth to deleting secondary cats will increase power gain?