MBNiko

Ive searched and found a couple threads about this but was wondering......

Has anyone replaced the primary cats with sport cats? If so, how much of a difference does it make? Im not too worried about the HP numbers im looking more towards sound and keeping the car "safe".

I already have my 2ndary cats and resonator deleted w/ a Eurocharged tune. Would love to hear from anyone input about this!

WaveyKat

high flow Metalic Cats :-)

ML63 AMG

A nice set of 200 cell metal core cats should help improve top end airflow without hurting low end torque. You may pick up 12-15hp, but don't expect more than that.

If you do primary sport cats, make sure you go to a competent fabrication shop that can TIG weld them, do not MIG weld primary cats, they will leak due to the excessive heat/pressure the primary cats have to endure.

Hope that helps

MBNiko

I wonder if anyone has done this on the forums WITHOUT headers. Headers would be the obvious and easiest step but I dont have the extra 1500 laying around. I dont know if I fully trust those $500 hearders from TopSpeed either on eBay..

MIKESV8

$1,500 for headers for your car? that's a steal really. i remember the ones i wanted wire 3-4 times that price when i had mine.

ML63 AMG

supposely they have sold hundreds of those ebay headers and all gotten positive reviews so I guess they are pretty decent for the price.

If you want to go another route you can do high flow primary & secondary/resonator delete. that will extract the maximum HP out of the stock exhaust system without touching the headers at all. All combined thats probably good for 25HP without touching headers.

MBNiko

I think I saw you were selling 200 cell cats? Are those metal core?

madmaxC55

Hi
I have removed both primary secondary cats and resonator, got a 28hp increase and a much more responsive throttle response, also the acceleration at on top gear on the freeway is alot smother, the noise is great too, one down side tho is that after about a week the engine light came on, although this does not effect the drive or performance of the car. And for $75 spent to remove the cats 28hp is a huge gane thats more than fitting sports cats for less the price,
So if u dnt mind the engine light to be on then i suggest do it, bt keep your cats, if at a later stage u want to sell the car just have them put back. Unless u know some way of turning the engine light off.without putting the primary cats back

MBfinatic

If you want to keep it safe would you consider just removing the secondary cats. I think you can get flowmaster cats cheap but its not worth the hassle. ^ Unless your going to get a tune I would leave in your primary cats to avoid a CEL.

madmaxC55

Removing the secondary and the res won't give you an engine warning light, so u can take it out and the car will sound amazing, i took out my primary aswell because they were melted, and i hate cats, i live in south africa i can do what ever i want to my car there is no law against it, and plus the proper authorities here dont know their *******s from their elbows, and that includes the mb dealerships here.
If u remove your primary cats and the engine light comes on to turn it off disconnect the battery, it will eventually come on again after a heavy rain, got something to do with the humidity in the air, just a short way of turning it off, u can get the cat sensors turned off indefinatly at a mb dealership.

ghiaguy

I've still held off removing the secondaries myself- wouldn't mind the power though. It got louder without the resonator, but I'm worried about the droning around town. What rpms are the loudest when cruising without secondaries and no resonator?

MBNiko

I have both secondary and resonator taken out. I dont get much drone, if any. Its loudest point is about 2500-3200 RPM, thats when its the deepest rumble, one that makes you smile You would enjoy it a lot more if you took them off, besides theres no negative drawbacks about doing such.

ghiaguy

Yeah- I need to just do it...

I've had experience with various imports exhaust, both NA and Turbo and fear that rasp and drone you get from the wrong combination. An AMG V8 can't possibly make unpleasant noises though!

I am hoping for something similar to the stock C63s as far as noise, and I think this will come close. Thanks for the recommendation!

madmaxC55

I only have the two silencers on the back, the sound while driving normally is not that loud its just a bit louder than stock, bt when u put your foot down its pretty loud but its a sexy loud lol, just take the res and secondary's out, it wont be as loud as mine and it will sound as good as the 63

ghiaguy

yeah, this has now been promoted to "this weekend" status, but the guy I can reliably count on to work around cats without a gripe is pretty sketchy. I can plan on a long wait even if I make an appointment - at least he welds well stoned... :/ ....anyone have an east bay muffler shop recommendation??

CALI_C55

I want to do the primary cats delete as well, but worried about the check engine light. My ECU is reflashed by Eurocharged though so I don't know.

ghiaguy

I'm in California as well and personally I would not touch the primaries. I have the secondaries off now and no resonator (not that it matters with emissions) and I just passed smog rather easily. The car sounds nice and my Eurocharged tune is dialed in to my exhaust setup.
If you remove the primary cats you will get the CEL. I'm not sure if you will pass smog with aftermarket primary cats and you DEFINITELY won't pass without cats...


How is that Eurocharged TCU tune working out for you?

CALI_C55

The Eurocharged combo is great! I haven't had any issues besides the fact it chirps on second when I floor it!!

Pansu

You can delete second lambda diagnostic using Star(MB diagnostic device), so then is no worry to get CEL

I dont have any cats and no second lambdas = no CEL (thanks for the Star)

MBNiko

Yeah, id say dont even try deleting the primaries.. If anything, wait to get a set of headers and they delete them for you and make some nice sound/numbers.