Sungkyo

Hello!

Picked up a brilliant blue GTS a few weeks ago:-) love it! I will be doing the Renntech R2 upgrade but not sure about doing the included Downpipes . Love the sound but worry it's TOO loud. For those that have done DP's....any regrets?

I realize I have cheaper options but going Renntech.

Thanks in advance!

boosting1bar

If you're in C mode there's really no discernible sound difference. In S it's certainly louder and S+ sounds like an open header racer with the valves open. You can close the valves in S/S+ obviously and quiet it down some but it's still noticeably louder. I drive my GT a lot and over fairly significant distances (500mi one way) and cruising in C there's no difference from stock. No drone at all to speak of. If I had it to do over again I'd do the exact same thing I did. I recently posted a review of my Renntech set up and thoughts on sound, power, etc.

AMG 17GT

Just delete the secondary cats. Big sound (not too loud) upgrade and car runs smoother.

Not sure how RT gets away with 5k DPs.

jchochla

Did you cut out your secondary cats?

rsalco

They've always been stupidly expensive. That said, their products and customer service are top-notch. But did I mention, STUPIDLY expensive...??

AMG 17GT

Yes. Simple cut out and replace. Do this first and then decide If you want DPs. Eliminated a lot of heat, 10 pounds of weight and car runs smoother and sound is glorious

AND no CEL as no sensors past secondaries.

AMG 17GT

Ha. Yes. We need to get in to the custom pipe business

emericr

Congrats on the purchase. I am glad to see that people are finally picking this awesome sports car.
The issue with downpipes is for resale purposes, you cannot put it back to stock as the OEM pipes need to be cut out unless you want to drop the transmission (insane option IMHO).
As AMG17GT said, the deletion of the secondary cats is the way to go. I did it on mine and with the sport exhaust, it's perfect.

300blackout

So you're saying there are no O2 sensors on the secondary cats? I guess this is a job for a muffler shop with welding capability?

jchochla

Do you mind posting a picture if you have one?

AMG 17GT

These are the catalysts cans. They get HOT.



They are located just in front of frame support where exhaust turns 90. Very simple. On the C63 these are forward about 6-12", so it's easier on GT.

In the past, I have removed resonators which were intended to reduce drone and high frequency noise. Here it's just another 7 decibels of the same sound an octave lower.

In comfort mode it's the same except a funkier bass at idle. Yes I luv it! Ha.

That's all I have on this mod.

jchochla

Gotcha. Thanks for the pic. Will definitely have to drop my GTS off to get them removed. Im guessing you're overall very happy with the sound now? How is the car in comfort vs. with the exhaust opened up?

jchochla

Yea, no joke! Lol.

DriveAMG

this sounds perfect to me. I love the way my car sounds I'd just like to have it a bit louder... and maybe barker😎

Can anyone post post up a sound clip or video of it?

Thanks!

Sungkyo

Thanks guys and all good info! boosting1bar thanks for your write up in an earlier post. As for deleting the secondary cats, did it effect the pops and crackles when de accelerating any? Would hate to lose that. If anyone has any sound clips of the deleted cats please post up.You guys are just having a shop cut them out? Nobody sells just a mid-pipe that bypasses the secondaries?

Thanks

smrtasp

Weistec appears to have both the downpipes and secondary section as part of their exhaust. It's also considerably less than the cost of Renntech. Not sure the build quality but the video they posted of their 10.9 quarter mile pass sounds really good.

emericr

The deletion of the secondary cats do not effect anything else that the car does (crackles and pops in S+). Just think of it as stock car with increased deeper sound.
Why buy a mid-pipe (don't know of any vendors having them) when you can get it done and fully reversible for a couple of hundred bucks?

Vic55

People buying into the name... they have their loyal base but I have to agree that the 5k is exorbitant in nature.

300blackout

ermericr, have you done this to yours yet? Could you provide any tips? I assume a new section of tubing would replace the secondary CATS. But I don't understand how they can weld on the new tube sections when the exhaust is still on the car?

jchochla

+1. And cost wise what is considered reasonable cost for something like this? Just wondering rather than having someone looking at a 100K+ car and throwing an outrageous number for a mainly labor job...

emericr

I believe I was the first one to do it .
It is not complicated guys.
Disconnect the battery just to be on safe side.
Cut the secondary cat with a hack saw, cut and bend a new pipe and weld new pipe on car (they have tools to weld around).
Any competent muffler shop performs this type of stuff daily.
You should not be paying more than $300 and I am including a lot of MB tax on that.

DriveAMG

can anyone post a sound clip???

garthbo

I'm thinking of removing the secondary cats/resonators as well. Since I know little about exhausts, can someone confirm that the ones crossed out in the pic below are the parts the should be cut out and replaced with a straight tube? (Pic borrowed from Dr. Graphx)

AMG 17GT

That's the ones

garthbo

I'm having my secondary CATS on my GTS removed this weekend. Shop here in Manila quoted me $185 for the job. Can't wait to hear the results!