Originally Posted by JSP321

Awesome news! Thanks for sharing Vic!!

How is the sound in comfort mode (valves closed)...is it about the same?

Originally Posted by JSP321

And...does this set up still have the ability to open/close the valves via the steering wheel button?

Originally Posted by Vic55

Just call me the crash test dummy --- I went to my local exhaust shop who has done alot of resonator and 2nd cat deletes for me on my M's. He doesnt have the cleanest welds but this isnt a beauty contest and I never had any leaks.

Anyways he looked over the rear oem section (mufflers) and said he could create a "Y" design where the valves would remain so I said why not.

What he did was replace the muffler with Y section using a wider inner pipe (no valve) than oem and then split the Y to valve side. How does it sound? MORE of the same great throaty V8 rumble with pops and bangs that are more accentuated. The best way to describe the car is its the same tone but with maybe 25% more decibels or volume UP Its a simple and reversable process too. I still cant get the valves to open fully pre higher rpms (3500 to 4k) as thats a program with the CAN but a VC will fix that. But for the price (350) its worth it to me 100%. I dont think the Renntech mufflers would that much of a gain if this gets me about 25% more with no muffler. Oh no CEL.

Powerwise, zero change in feel although the more free flow could have a tiny gain = negligible at best IMHO. But I didnt do it for that.

AFTER (Valved section is outer) The set up is more of a straight back direction vs the OEM muffler which passes out the side and then back.



BEFORE

Originally Posted by theprototype

Do you notice much of a difference with the valves closed vs open? Looking closer at your layout I’m wondering if there’s not much of a difference between the two. Going to a muffler shop today and may just show them your pics and have them replicate it but also wondering how a straight pipe to the valved section with the offshoot to the second one would sound.

Originally Posted by Jordywilson

So is the consensus that there is no way to get aftermarket downpipes (either with or without catalytic converters) without having a permanent CEL? I was wanting to get downpipes before a dyno tune if possible (still waiting to hear if the 2025 ECU can be unlocked for the GT 55)

Originally Posted by Vic55

my local Benz master tech said the DME's are hard to unlock and then their is lack of demand (he tunes a **** load of Benz cars over decades). So you can do the dps but I dont see any readily available validated tune so the CEL will prevail; plus doing dps is a load of work (drop the tranny).

Originally Posted by Jordywilson

Is it not possible to swap the downpipe by just doing a clean cut without dropping the tranny? I’ve seen other people do it on other cars, but I don’t know the exact config/placement of our exhaust system