Hi all,

I am contemplating removing the secondary cats on my C43 ( 5.4ltr ) , but not the centre muffler.

I dont mind if the car gets a bit louder, but dont want it to change tone too much, i still want it to sound like an AMG.

Seems most are removing both, i cant find much info on removing just the cats.

I would imagine the cats wont have as much impact on the actual tone of the exhaust compared to the centre muffler.

I also dont want to lose power, more power up a bit in the higher RPM would be good though. The 5.4ltr does seem to be holding back a bit above 5,000rpm where the 4.3ltr didnt.

Please dont suggest i remove the stock secondaries and put in aftermarket cats, because im not going to do that.

Cheers all

 

I don't have the 5.4 but removing the secondaries cats and not the as you said middle muffler shouldn't make the car loud at all.

Interesting that your engine holds back after 5k rpm. If you're willing to try out my air box and elbow to see if that fixes the issue let me know.

 

Ive modded my elbow as per the way you do yours, which did make a very small difference.

I also removed the mesh from the MAF, hard to say if that did much, i put it back in, then took it out again, very hard to say if its better, but its certainly wasnt worse.

The plastic MAF screen is still in there and im not taking that out, it serves a purpose.

I have not removed the mesh from the air box or cut any ribs out.

Changing to the 5.4ltr engine with nothing else changed did make the exhaust louder than the 4.3ltr. My 99 E55 was far quieter than even the stock 99 C43.

 

I dont think thats gonna make it louder.

The resognator is basically a silencer.

I have no tesognator on mine and its louder than stock but it seems a bit quieter than the 4.3

 

I spent a long time debating on the secondary cat and resonator delete, because I wanted a bit more aggression but I DO NOT want a loud and stupid car. At the end of the day it's a Mercedes Benz and I commute great distances in it. I don't want to call to much attention to myself or have insufferable drone on the highway.

It's really not bad at all. It definitely made it sound more aggressive but no drone and it doesn't attract enough attention that people turn to see what the sound is.

My car seemed louder when i did the engine swap, too. I still had stock exhaust at that point. But I honestly don't think it was louder, just the tone of the exhaust got much deeper so it reverberates through solid material much easier than the higher tone of the 4.3. I could "feel" the exhaust better but it was still a pretty quiet car.

 

 

heres what a mercedes sounds like

 

I havent modded the box in any way. At most i would only mod the internals and remove the mesh, so if any of that works well i would look at doing it, but not cutting the box open.

I had the battery disconnected for over 24hrs when i replaced the O2s last week, and went on a 1,400klm round trip in the past 5 days. The car runs smooth, just seems to taper off slightly in the high RPM.

 

What did you remove?

Have a look in my profile, im not too concerned about attracting attention, just dont want it loud! Had all that with my Corvettes!

 

I removed secondary cats and resonator into a Y collector. It sounds much more aggressive but definitely isn't loud.

 

Awesome, thanks mate

Im in the middle of giving it a full Liqui-moly treatment at the moment, did the intake, which didnt yield much smoke so it cant have been too bad, just got the oil detox in now.

 

My c43 has the secondary cats and central resonator deleted and replaced with a Y pipe. This is the usual exhaust mod that most owners go for. IMO it's perfect just for cruising around with a nice purr and loud roar (but not too much) with WOT.

Some videos I made before and after

 

Yeah seen those ones mate, its probably a shade too raspy for me these days!

On my 1994 Corvette i had tri-Y long tubes into 3" pipe, X-pipe into 3" stainless cats, and then 3" pipes straight to the rear tips. No mufflers at all. It was extremely deep in tone, and did sound perfect for that car. It was quiet for regular driving, silent at 110kph, and roared like a monster at WOT.

Got a video of it here from before the mufflers were removed, but its done many years ago with a digital still cam and the sound is terrible.

 

You can envisage just doing the resonator delete and keep the secondary cats. The secondary cats will kill some of the excess noise. I think Kowalski has this type of setup with a beautiful OE type Y pipe with standard gaskets, clamps, etc..

 

highly recommended part to buy from german ebay!
shipping is cheap

 

This was my biggest fear with doing the mod. I was okay with increasing the volume a bit but I did not want raspy, "redneck" sounding exhaust. I wanted my AMG engine to still sound refined and muscular but not sound like an 80's pickup truck with a straight pipe.

My fears were unfounded. It doesn't sound anywhere near as raspy in real life. Brand new Mustang GT is louder than my car still. If you're familiar with them, after the mod my car is about as loud as an earlier 4.6 Mustang GT, like a 2000-2004 era Mustang GT. They weren't loud as far as muscle cars go, but you could definitely tell them apart from regular cars in traffic.

 

We have Rustangs here yeah, but theyre almost like Corvettes, very few people actually drive one daily.

I wouldnt buy a big piece of tube from overseas though, not when it can be done here for half the price!

Im not removing the resonator, its not going to be a restriction in the exhaust like the cats could be. Your car in the videos is too loud for my liking.

 

This looks like the first and most essential mod I'd like to do to my C43.

Do you have a link to any Y pipe suppliers?

 

You can buy this one. 2.5 on each side. Than 3 that goes to your single outlet. You want that 3 to go out.

 

Well I certainly wouldn't remove the muffler, as AMG engineers worked around that to create a special sound. Secondary cats and resonator delete leaving the stock muffler is the way to go IMO and replaced with a Y pipe as previously mentioned

Regarding the "holding back" as you say above 5'000rpm with the 5.4 M113, I guess that's normal. Don't forget the 4,3 M113 has special AMG cams which you can definitely feel when the engine comes "on-cam" at 4'000rpm and above. The 5.4 has standard cams...

 

Hi,https://mbworld.org/forums/c36-amg-c...3-bj-99-a.html

Regards
Jens