Mr.Benzo

I didnt really notice the difference until a couple of days after, and I really like it. I am now considering removing the secondary cat as well!

misfire84

Yesterday I had both secondary cats removed and the resonator ... Wow !!!! it burbles on idle and if you floor it it roars but if you just cruse along it is like normal . all thes observations are from the driving seat . an excelent mod !!! ( 150 GBP)

C55Newb121

I will be deleting my resonator and replacing the secondaries with high flows. Anyone know what the best high flows are? Also, What is the inlet pipe diameter on cats?

c32kompressor

you wont regret it, it almost sounds like a deeper and throatier vw r32

C55Newb121

after reading around on the forums, i think what i might do is first start with the resonator. my initial thought was to go with high flow secondaries, but unless i open up the restrictions of the stock exhaust manifolds, it wouldn't really be worth the $200 plus for the race cats + installation.

jturkel

well actually, on the C55 you can see some gains from deleting the secondary cats. about 8 or so WHP IIRC. on the c32, there are no gains. while the stock C55 manifolds are restrictive, you will still see gains if you leave those on and delete the secondaries.

the real power to be had is with long tuber headers.

C55Newb121

touche dr. turkleton...

I still almost think the money would be better off spent towards a set of headers instead of high flow cats....

ideally, I want to start with something like the AEM F/I controller and do my own tune, but I think that could be dangerous. lol. Don't want an AMGoBoom....

I wonder how the Kleeman or Renntech ECU tune works with exhaust upgrades and intake upgrades.

Mr.Benzo

how much money are you guys paying for the secondary cat removal? and are you just having an aluminum pipe welded in its place like the resonator removal ? or do I need to purchace some special piping?

97W202

had my secondary cats and resonator removed yesterday and wow does it sound bad ***.. and I hear it only gets better after 2 days!

I spent a high $150 for everything including installation but I am happy with the work... kept my resonator and both cats...

anyone know how I can check for exhaust leaks? want to make sure I get the problem corrected if there is one...

riverace

I had the res-delete done over a month ago and I love the sound, I wouldn't mind it being a bit louder but I just don't want it to be over the top and obnoxious. I keep thinking about pulling into a gas station in Norcross two weeks ago and an E92 M3 pulls right next to me with a modded exhaust, it sounded scary, I kept thinking my C55 was hiding behind the pump, wouldn't be bad to have that growl. The other part of my dilemma is that I don't think there would be many shops around the Atlanta area that would do this for me, the one shop I went to I bounced it off them and they said they wouldn't do it because they could get heavily fined. So I'm kinda stuck at the moment on what I should do, Id love to mod this thing and have several options, but at this point it looks like its the end of the road for me, there's not a lot of low cost or worthwhile upgrades for a C55 IMHO, not like there were for my M3.

97W202

keep looking man, eventually you will find a shop who will remove those kitties and it'll be worth the money.. TRUST me. I only have a c230 u my friend have an amg. the sound is from night to day but only in the high rpms.. cabin noise is vertually the same so no annoying exhaust note in your ear !

whatthecrunchyo

I just went and got this priced for my C55 after reading this thread. He said $150 + parts ($15-$25) for deleting the resonator and two secondary cats, going with a y-tube to 3-inch galvanized aluminum. This is a rip, is it not?

C55Newb121

I called Midas today and they quoted $50 for the res delete. I would end up going with high flow cats, but that does seem a little high. Just shop around and make them compete for your business.

If you tell them another shop in town quoted doing it for say $50 less, I bet they would come down.

jturkel

haha....the funny thing is that that isn't even that far off from my name....lots of people at my medical school call me turkelton or some variation of that. go figure.

but yah, if you want serious power.....long tube headers. i mean, high flow cats + deleted secondary cats + resonator delete (weight savings maybe?) might net you a combined 15 or so whp max....but the TRUE bottleneck is the stock manifolds. i remember seeing hooley's (MBH) headers on his 55...made tons and tons of power. the longtubes will take care of the need to go to race cats anyway....and then deleting the secondary (or going to high flow secondary) and resonator might give you a little more at this point (since the main exhaust flow bottleneck has been resolved).

I know renntech does a great job with tuning. i have their tuning on my car (in house at dynocomp in scottsdale) and my shop (and i imagine most shops) will adjust your timing/fuel/etc accordingly to best complement your car's modifications (exhaust, intake, etc) after they do a baseline and then transfer the premade tune to your car (and then afterwards, the fine tuning begins).

regarding doing your own tune, i think there is a guy or two over on the srt6 crossfire forum (srt6 has same motor as c32, though yes i know you have a 55) who is working on (or already completed/finished/has) his own tune. i haven't checked over there in a while though....way too busy with school....i shouldn't even be on here. i had a test today and two practicals tomorrow....back to work i go

320 dreamer

for the 32 if you do a res delete and secondary cat delete you may experience some drone. what i did was replace the oem y pipe with a magnaflow x pipe and my drone is all but eliminated. just food for thought.

whatthecrunchyo

Hey guys, after reading this thread, I decided to go ahead and do this to my C55. I got both, my resonator and secondary cats done for $90 (he got to keep my cats, I got to keep my resonator). My impressions are this:

The car is still very quiet when you are just driving normal (which I wanted). It is so quiet in fact, your girlfriend won't make fun of you for being a boy-racer. However, when you step on it, you can definitely hear it. It sounds like that V8 that I'm sure many of us were expecting to hear when we bought our car. I don't know about you guys, but when I revved it for the first time, I was like, "Huh?"

In short, it is very very very far from obnoxious. It is very quiet when you want it to be, and just loud enough to enjoy the V8 symphony when you want to get on it. If you are looking to attract attention with the loud V8, you will be disappointed, but if you want people to say, "Man, I sure do like how your exhaust sounds," you will love it

jturkel

just wait....in two days or so, the sound will likely be deeper and a little more aggressive, but not droney or annoying under normal driving.

notice maybe a little pickup in power?

whatthecrunchyo

I'm not too sure if I did or not. The car is still fairly new to me so I can't really tell if it's more powerful or not. But if it is, hooray

Here is a video of it as of day one:

http://www.youtube.com/watch?v=BumH_AURCZw

loudandheard

I would say caution with using aluminum, I heard that it does not hold very well with heat and in exhaust, but that's all I've heard. I do not know how true that is.

Definitely a big difference and for the money this mod will put a big grin on your face.

whatthecrunchyo

Yeah, sorry. I misquoted. Aluminized steel, not aluminum.