johnsopa

I'm using the OEM steel center muffler from my 991.2 GT3. I also have Cargraphics race headers.

SGOGT4

Jamie@dundonmotorsports

Couple things

The kit comes partially assembled, don't disassemble or it will make the job a bit harder. The bracket looks odd, but use it as it's assembled, the angle is important.

When I drive our car with cats and quiet and loud I don't hear much if any drone down to about 2100 rpm, between 1500-2100 there's a touch of drone,

Drone is also a very personal thing, some people say non-valved side deletes on a GT3 don't have drone, to my ears they drone like crazy.

If you have questions about the install feel free to give us a call at the shop (and sorry about not sending the bolts, will get those in the mail tomorrow next day air).

As far as the size of the cats, the way our headers make power, it doesn't matter so much, and yes the 200 CPSI metal core cats.

Thanks!

Jamie

Jamie@dundonmotorsports

Yes everything loose, give us a call at the shop and Charles can help step you through it.

benben01

@SGOGT4 You done yet? Many of us are waiting.. hehehe

SGOGT4

MVEED3

I went the reverse route of everyone and did the GT3 muffler conversion first (TPC kit) since others experienced drone at lower revs. The drone is tough to pic up with a mic so vids don't tell the true story. I wanted to proof my tolerance in a dual-purpose car. To me, the GT3 muffler conversion with OEM cats in place still droned unbearably for a street car. This is coming from a guy that installs exhaust on every former sporty car. The Akra setup on my last V8 M3 had drone but it wasn't offensive.

This tells me it would only get louder with any aftermarket header setup so I'm hoping to find a local ride in a full catted setup with the DMS quiet muffler.

For installation tips...

1. Rotate the V-bands so bolts are not facing the half shafts, especially from seeing SGOGT4's pic.
2. Install the elbow pipes to header pipes with bolts inserted, but not tight, before fitting the remaining exhaust pipes. This way, you aren't fighting for alignment of those flange bolts.
3. Tighten from the header flanges back. So, flanges>>V-bands>>tips. This will net the best alignment without any back-and-forth to get the tips perfect.

ajw45

I have the Tpc kit too, drone is extreme with the RS box between 2k and 3k rpm with part throttle, I assumed cats would have helped with that. Everywhere else though it sounds so good and the power gain is seat if the pants noticeable enough (and dyno proven) that I could live with it, just gotta use cruise control on road trips to minimize larger throttle openings and big drone. That said, I've been running the akra for the past few months and I've been enjoying living drone free too.
For me, the DMS quiet exhaust has noticeably less drone than the RS unit but still a lot of drone compare to stock pse with basically none.

SGOGT4

Charliekay

Keen to see this too, you are the only one that I know of that is running a GT3 exhaust with the cats. It doesn't seem like the OEM or Dundon rear muffler makes a difference but the catted Dundon conversion kit might be difference.

I recently did a GT3 conversion (without cats) as well and it drones horribly at partial throttle under 2000rpm and tapers off to non-existent at 3000rpm.

From what I know the tune is done for the runner w/ PSE but the issue is heat build up from the exhaust gases not having enough flow.

SGOGT4

BillC3

Unfortunately, the Akro muffler also drones. It just does it at a higher pitch than the stock or GT3 muffler (first-hand experience).

ajw45

Are you talking about the akra gt4 muffler or the akra gt3 center? The akra gt4 exhaust seems drone free for me, have been wondering about the akra gt3 center on a gt4....

Charliekay

I think ajw45 is referring to the Akra GT4 exhaust rather than using the Akra GT3 muffler.

benben01

Maybe you guys's hearing is much sharper than mine.. The drone under 2k'ish is character for me and really is not that bad IMHO. Again, this is highly subjective. I am going to mod my TPC pipes to include 200 cell cats this coming week so I can be a little bit more environmentally friendly