I have a new '09 C63 100% stock (for now) and I LOVE the exhuast, its obviously one of the car's strongest points. But i was wondering if i were to just remove the resonators on the stock exhaust, exactly what it would do (both sound wise and long term effect). I guess what im trying to say what are they pros and cons and would you or would you not suggest going through with it?

 

i have the same question of the secondary cat delete. what are the pros and cons? are there any power gains or is there power loss?

 

From what I read the exhaust on the C63 is a tune exhaust meaning that it has been bench tested(in a dyno or something) to not produce drone but still be quiet at iddle and throathy at WOT.

You need to be carefull because you might not like the drone. The drone typically occurs in the lower rpms and it might become unbareable during long trip becauase in the top gear is where you normally get the drone.

 

Do NOT remove the resonator unless you install an "X" pipe. The resonator has a built in equalizer cross over pipe. They are a straight through design and keep drone from inside the car. They do not slow down or interrupt the flow.

I would recommend removing the secondary cats if you are just looking for more sound. You will pick up a little power but not enough to feel. Removing the secondary cats will make it significantly louder. Good luck!

 

I have both 2nd cat/reso removed and replaced with straight pipes with no x-pipe. There is no drone and its extremely loud.

 

There are some videos on youtube of a C63 with a resonator delete. Doesn't sound too good imo. The stock exhaust sound is perfect on this car.

http://www.youtube.com/watch?v=p1Sq83bbwgw

 

heres mine w/ GTPro's x-pipe (2nd cat delete), and i left the resonator in place

http://www.youtube.com/watch?v=0C7KTFwv7D8

 

You can remove the resonator if you want to but when you do you remove the equalizer pipe between the two banks(sides) and therefore potentially reduce power. I would add an "X" pipe if you plan to remove the resonator. You can take the cats off and increase the sound dramatically and performance to some degree.

 

how much power do you end up losing if you lose any at all?

 

Yeah please let us know. I just got my resonator removed, and i think it sounds awesome especially on downshifts, thinking about the x pipe if there is some hp increase..

 

I also deleted my resonators and replaced with 2 straight pipes. The sound is almost identical but louder. You'll notice a lot more backfires especially in 2nd gear. Downshifts are much more aggresive, but most of all cold starts are incredibly loud. To a point where I worry about waking my neighbours when I start my car early in the morning or late at night. I've also noticed a lot more of that AMG gargle.

What Dadsc63 says is correct, and there will be a power loss roughly 1-10 hp I believe, but the loss is hardly noticeable and from what I've seen there isn't any dyno evidence to prove it at all. From personal experience the noise in the cabin is relatively louder but not to a point where it becomes annoying, and I've certainly not experienced any drone, and I believe a lot of people with resonator deletes can vouch for this.

Overall, I do recommend the resonator delete, the pros heavily outweigh the cons. Also keep in mind some shops, will refuse to do a secondary cat delete as it does conflict with emission laws (at least in Canada). Also lets keep in mind that the x-pipe should not have an advantage over straight-pipes or h-pipes unless the headers flow DIRECTLY into the x-pipe I believe.

 

i have the same exact set up. yes no drone. quiet when you want it quiet very loud if you want it loud. not really any gain or drop in power as well and ive had mine for about 2 years now no problem.

 

where can i get a straight pipe to replace my resonators?

 

Go to your local reputable exhaust shop. Ask them to cut your resonator out and replace it with a Straight pipe.

It should look like this once they do it.

PS: I see your from Hawaii, Im sure there are a few places (even hot rod / restoration places) that can do it with ease for you.

 

I have had mine done yesterday and love it, and so the horsepower you do lose is so small you wouldn't even notice it? After i had it done thats all i was worried about is if i had any hp lost. Some people were saying you could lose up to 45hp but thought that was little bit far fetched. I haven't really noticed a hp difference at all. I mean the cars are governed anyway so its not like the 10 percent horsepower lose would make any difference in the USA.

 

That would be ridiculous, I'm sure others can chime in, but the only reason you lose hp is due to a drop in back pressure from the delete, I highly doubt you can lose up to 45hp, thats pretty significant, and is implying the fact that the air flow through the resonator is attributing for a significant amount of power.

 

Would also like to add that the resonator delete if anything would influence torque and not hp. By deleting the resonator you are changing the stock airflow and essentially changing gas velocity and back pressure. It is all about keeping gas velocity high.

Too put it simply, long narrow pipes help improve gas velocity at low rpms, but short wide pipes are optimal for high rpms, so essentially you must choose between one or the other. (mind you there are pricey headers out there which can acheive both). By deleting our resonators and replacing with a straight pipe, we can argue that we are trading off low end torque, for a louder sound.

 

You are correct, by removing the Resonators you do not lose any power, nor do you make any power. Removing the secondary cats will free up some extra ponies.


Go for reso delete / second cat delete guys. Its been done many times before with success.

 

I'm going to straight pipe my 2nd cats and resonators

 

what material should the straight pipe for resonator be made of?

 

By the way Kriston thanks for the recommendation to zoro muffler! Was unsure at first but work was a quick in and out and was good quality for a great price. But unfortunately they told me they wouldn't do a secondary cat delete; wanted to do both all at once .

And Mikey they're suppose to be stainless steel, make sure they arnt aluminum

 

they will just replace it with a regular pipe or at least thats what they did with me so it will just be another regular pipe.

 

pros: it's easy and cheap, also no drone at all. if there is, it can't be heard over road noises.

cons: IMO (others may disagree), the sound is too unrefined. there's a distinct snap and crackle (i guess people call this 'rasp?') at the top end that is a bit excessive. sounds like an angry trumpet going BLAHHHHHH-P!!!!!!

here are a few clips of my car when i had it (all stock). the parking garage clip is what drove me to buy a catback system.

angry farting trumpet (aggressive, maybe.. but too unrefined for my tastes):

so loud, it echoes off of trees! (maybe you fancy this)

now with an eisenmann race exhaust (loud but more controlled)

again, all subjective

 

No problem,

But thats odd, did they say why they won't remove it?

 

I just made the switch to an Eisenmann race setup on my car as well.

Having the reso delete is a great way to get a very aggressive sound, I personally enjoyed it.

The Eisenmann race setup is definitely a more deeper tone compared to the reso delete. I had my brother take it out for a boot around the block. Sounded like an angry grizzly bear. Had such a deep aggressive tone.

Now I'm thinking how the race setup will sound with a secondary cat delete??.