Author Topic: Mk7 GTI OEM Muffler / Silencer modification  (Read 2271 times)

Offline DCmk3

  • Here all the time
  • ****
  • Posts: 406
Mk7 GTI OEM Muffler / Silencer modification
« on: 23 April 2021, 08:29 »
A simple effective way to add some more volume, improve overall flow & still keep it civil and have zero drone in the cabin under any conditions.

To start off with a comparison between the beloved CSS/CS silencer design and the GTI (non PP) silencer

Above is the CSS/CS silencer design which has overall larger diameter piping but also a better flow design overall.

Above is the factory GTI silencer design which forces all of the gasses into the center perforated tube (which is capped at the very end) forcing exhaust gasses to evacuate through the small orifices into the rest of the silencer.
The vertical bars have perforations in them which allows gasses to flow into the rest of the chambers and cut down noise.

What we did was cut a window in the center on the top side of the silencer so it can't be seen once completed.
Removed the plate/gusset closest to the end to allow for room to work and weld on the new section.
The fiberglass matting/sound deadening material in the center section was removed leaving just the two side chambers with the material in it.

Formed a nice merge in the appropriate sized stainless tubing, cut off the end of the perforated tube and welded this new divider in to allow direct exhaust gas flow out towards the exhaust tips.

Leaving a portion of the perforated tubing intact to retain some silencing capabilities and to avoid having an obnoxiously loud exhaust.

Two videos to give some idea of the sound - of course the dyno room video is a little louder than it is because of the closed in building.

After all is said and done, it has zero drone, there's a noticeable volume increase however cruising and idling it is still sounding tame with a bit of a deeper tone until you get on the loud pedal and it wakes up just as one would want.
« Last Edit: 23 April 2021, 11:23 by DCmk3 »

2014 Mk7 GTI

Offline fredgroves

  • Serious forum addict
  • *
  • Posts: 7,125
  • Professional Um Bongo drinker
Re: Mk7 GTI OEM Muffler / Silencer modification
« Reply #1 on: 23 April 2021, 08:58 »

This is similar to mods I have seen to stock exhausts on BMW's.

Should give a bit more noise without getting an ASBO and without resorting to expensive replacement parts.

Great writeup!
Current: Mk8 GTI DSG, Adelaides, DCC, HUD, HK, Winter Pack, Rear Camera.. Aka "HMS Weasel"

Gone: 2017 Mk7.5 GTD,manual, NavPro
Gone: 2014 Mk7 GTD, manual, NavPro, DCC