SL/R230: Resonator Removal
Junior Member
Joined: Dec 2018
Posts: 43
Likes: 8
From: Texas
2015 SL400
My advice:
1. Initially, I just removed the rear mufflers and installed straight pipes. It sounded like a Mustang. Lost low RPM power but reckon more power on higher RPM range. Cabin noise was unbearable. During cruising speed, the sound of the drone prevents you from chatting with your passenger. It does indeed sound nice from the outside but too loud for my liking.
2. Installed the mufflers back on and removed the secondary cats. Perfect! There was more power (or maybe it was just the sound). Cabin noise was the same as stock. The sound from the outside was amazing. There was a slight growl and it sounded like a performance exhaust. The sound was way more refined than my initial mod. After the ECU got use to the new exhaust, it was even more enjoyable.
3. I would want to try the Top Speed Pro 1 Perfomance exhaust with my secondary cats back on. @brentsl550 needs to stop tempting me with his videos!!
2003 SL 500 R230 - By the way, my mechanic told me that the 2003 models do not come with resonators. So basically we have primary cats, secondary cats and then the mufflers.
Cost: $300 CDN for labour and non-rust pipes for muffler. $150 CDN for labour and non-rust pipes for secondary cats.
1. Initially, I just removed the rear mufflers and installed straight pipes. It sounded like a Mustang. Lost low RPM power but reckon more power on higher RPM range. Cabin noise was unbearable. During cruising speed, the sound of the drone prevents you from chatting with your passenger. It does indeed sound nice from the outside but too loud for my liking.
2. Installed the mufflers back on and removed the secondary cats. Perfect! There was more power (or maybe it was just the sound). Cabin noise was the same as stock. The sound from the outside was amazing. There was a slight growl and it sounded like a performance exhaust. The sound was way more refined than my initial mod. After the ECU got use to the new exhaust, it was even more enjoyable.
3. I would want to try the Top Speed Pro 1 Perfomance exhaust with my secondary cats back on. @brentsl550 needs to stop tempting me with his videos!!
2003 SL 500 R230 - By the way, my mechanic told me that the 2003 models do not come with resonators. So basically we have primary cats, secondary cats and then the mufflers.
Cost: $300 CDN for labour and non-rust pipes for muffler. $150 CDN for labour and non-rust pipes for secondary cats.
Member
Joined: Dec 2017
Posts: 198
Likes: 44
From: Pacific Northwest
2011 SL550
i have a 2011 SL550 as well. Your car has primary cats, secondary cats and mufflers. The secondary cats are located in line with the doors. Search the forums and look for a "secondary cats removal" thread by Aussiesuede, he clearly has done all of the footwork and it was his write up that convinced me that this was the way to go.
MBWorld Fanatic!
Joined: Mar 2008
Posts: 1,232
Likes: 168
From: Glasgow, Scotland, UK
SL 350 R230 (3.7L with AMG Speedshift autobox)
I am looking at removing my resonators too, I have a really good exhaust guy that makes any custom set up so will update in due course.
MBWorld Fanatic!
Joined: Aug 2005
Posts: 3,085
Likes: 59
From: Los Angeles
2009 SL550 Roadster Diamond White, 2008 CLK550 Coupe Obsidian Black
I think so from what I remember. Mine were attached together with a bracket as well that holds them together (so looks like two large soda cans with a metal bracket). The car doesn't have a resonator(s) in the rear from what I remember on the 500s and 550s,
Last edited by gaazmon; Apr 24, 2019 at 01:31 AM.
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Newbie
Joined: Dec 2016
Posts: 9
Likes: 2
2003 SL500
This is correct. As they are downstream from the downstream oxygen sensors (which sole purpose is to monitor catalyst efficiency), you can pass a plug in emissions test with them cut out. Having said that, part of the emissions test is to visually verify all emissions components are in place and not modified or removed. Thankfully since its just an OBD2 plug-in test these days on 96+ vehicles, most inspectors wont look underneath the car.
I am an emissions inspector myself and live in a county with no emissions testing. My SL500 had both downstream cats removed aswell as both mufflers removed so it's straight-pipe from the primary cats back. Is it loud? Sure it is but that's what I wanted. Does it smell? No.
I am an emissions inspector myself and live in a county with no emissions testing. My SL500 had both downstream cats removed aswell as both mufflers removed so it's straight-pipe from the primary cats back. Is it loud? Sure it is but that's what I wanted. Does it smell? No.
Junior Member
Joined: Feb 2020
Posts: 20
Likes: 4
From: Dallas, TX
2008 CL63 AMG
Make sure you have the shop install an X-pipe and increase you're pipes to 2.5 all the way to the mufflers. Magnaflow is the best for the R230. People love the sound of mine with those mods. I want go to 3 inch exhaust later.
Senior Member
Joined: Nov 2008
Posts: 324
Likes: 37
From: Wichita
Plays With Cars
Your exhaust is only as free-flowing as the most restrictive section. Splicing in a section of larger diameter pipe won't help anything, though it could change the exhaust tone slightly.
