AMG 17GT

Second gear shift is a cannon shot lol. ......but overall you all should love this mod. Especially since you can turn a knob and it's all normal again.

Scares the hell out of 911s..........

FDNewbie

Someone makes 2-piece downpipes for our cars, right (so you can replace without having to drop the trans)? If so, may be worthwhile to replace the whole DP. Yes it'll cost about a grand more than just deleting the secondary cats, but almost any FI car (with an appropriate tune) will benefit from a more freeflowing exhaust...

AlexZTuned

You're missing the point... Obviously there is more power to be had installing catless downpipes, but in my opinion it doesn't sound good (way too raspy), and the smell is not desirable for this type of car (I've had decatted turbo cars before, they all stink). Not to mention, you will throw a CEL if you delete the primary cats... meaning in addition to the extra money spent on downpipes, you're now buying a tune as well even if it's just to turn off the CEL.

The secondary cat delete is purely a sound mod that doesn't require any tuning/coding... cut it out and replace with pipe in a few hours and you're done.

FDNewbie

Fair enough. I'm wondering if FI (who apparently makes 2 piece DPs) will sell just the second part of their DP? Then you'd have a plug 'n play pipe to replace the secondary cat with...or is this not even worth doing for those who have already done this mod?

Sanch

Vic, I took your advice mate - Drove it over the weekend to get the real sound and difference. You can definitely notice the difference right away.

- Cold start is LOUD!!!
- After 2k RPM you can hear the difference it is louder & deeper
- The downshifts pops are 20-30% louder
- More pops reving in Park mode (please find link to video below - apologies this is the my first video post)

But this video will show you the difference between your cars I guess.

I will try to get more when I can get someone to hold the camera

FINALLY - DO IT... DO IT NOW! lol - I wish I had done it sooner

AlexZTuned

Sounds so good

Any pics of the actual cat delete pipe under the car?

Vic55

yessssssssss the man!!!!! Ill be out to do that this Saturday. I love the pops at lower rpms to add. I have watched my guy do this (resonator version) in about 40 minutes. I have a feeling this might be a little longer due to the location of removal.

C63SEd1

Look at page 4 of this thread. I posted a pic. Here's another one.

C63SEd1

Finally, the weather has been nice over the weekend, and have been driving top down. The exhaust sounds amazing. Downshifts sound like explosions.

Originally, I wanted to replace full exhaust with aftermarket, but don't see a reason now.

Vic55

Yes indeed, with the valves wide open- the oem exhaust is hard to beat. Its the same with the GTS thus the post cat removal is such an economical gain for sound. I have always felt that Benz makes some of the best sounding OEM exhausts out there while I struggled with my last few M's (in stock set up).

Sanch

+10000000000

Sanch

It took 3 hours total! - I left it there and picked it up later on.

skim7x

Anyone in the DFW area do this? I'm tempted, but would like to hear it in person... Doesn't sound that great from videos, but I'm sure cell phone microphones don't do it justice...

Sanch

I agree, you really can't capture the true sound over videos. I was on the same boat as you... I was very hesitant, eventually I gave in.

I do not regret it for a second now that it's been done.

You can hear the sound inside the cabin a lot more too - with the windows up and music playing.

See63esS

Sanch,

How is the difference with the exhaust closed? Is it still modest? Any drone on the highway?

I want to do this but want to make sure this is still something that is fairly tame when the Mrs. is riding with me.

rbohgan

mine sounds same with exhaust valves closed. same as stock i mean. so its real quiet. also SANCH my car sounds nothing like yours on revving in park. maybe its that software update im lacking?

shoe3k

If the rear mufflers were left alone the drone should still be the same since the mufflers take care of the lower frequencies. The removal of secondary cat usually affects the volume of the higher frequencies, which most people associate with rasp. Personally, this mod gives the car a more raw sound throughout the rev range. If you have the performance exhaust (valves open) coupled with the secondary cat delete the car will sound brutal (awesome).

Davesc63

Did you just have the secondary cats removed?
What did your local exhaust shop charge?

Sanch

With flaps closed you can't hear anything... just like oem.

Sanch

Yes, it was very hard to find a place to do it but eventually did found one.

It's anywhere between $500-650 AUD - I paid $650AUD

Slowlane

Great info guys! I think I will have this done on Monday. I will post my results.

Aussie Zinga

Hi Sanch, I'm looking at getting this done after the 3000km diff oil change.

Could you please send me the details on where you got yours sorted, much appreciated

C63SEd1

My shop in NJ took about 1.5 hr and charged $225.

-GHOST-

What was the name of the shop in Nj?

C63SEd1

Broadway Performance in Clifton 9739305680. Authorized dealer for Eurocharged.


KC Custom Exhaust in Ramsey wanted $250