Jrtaylor9

I just picked up my new UV RS. I've owned several 997 gt2/3/RS. This is my first 991-anything. Clearly it is an ENTIRELY different beast from prior GT3's. I had/have RSS or SW bypass on all my 997's. PNH installed an RSS on my 991RS before delivery. I'm surprised how much quieter a bypass is relative to what I'm used to on 997 platform (yes, I'm in sport exhaust mode).

1) are there any of the open/closed flap issues like on 997s (I keep mine open with bypass)?

2) is there anything materially LOUDER than RSS? I chose RSS over SW because my experience is that it is the more aggressive of the two.

The car is purple with a giant wing and decals. So, I'm not going for any kind of stealth thing: louder, the better. I'd like to avoid doing full-blow exhaust-back-to-headers swap. I'd like to keep it in warranty and fairly oem. But I'm guessing swapping for a different bypass probably won't make it that much more aggressive since they are all fairly similar design?

Brosef

if you already have a center bypass, I would just add headers with hi-flow cats. should take the volume up a notch or two, but will still allow you to keep some civility with the valved side mufflers.

PhilT3 (PT3)

I went through almost every exhaust configuration possible. All the way from complete system change to full straight
-open and everything in between. I've found the best sound and volume is long tube headers, no cats, valved side muffler bypass pipes and factory(or akra) center muffler.

By the way, for what it's worth...... the other RLer who's went through all the configurations (Matt Moreman aka Money2XXX(?) Matt also ended up on the same configuration.

Guest89

GMG is louder than SW or RSS when considering only bypass. I have GMG and fabspeed catless headers

Jrtaylor9

Thanks for the feedback. I considered GMG. I'll check out the above suggestions.

John@Fabspeed

Phil said it best, the golden ticket setup on the 991 GT3 is a header upgrade and side muffler bypass pipes with the factory center muffler

TRAKCAR

Agreed, for less theoretical warranty loss a middle of the road option is keep cats and just do side muffler delete with a OEM center or stronger, cheaper after market muffler.

I haven't broken anything yet on the 991RS but I'm probably one of the first to do so and that's why warranty is important to me.
Just testing to see what cracks first on a 991RS, once replaced I'll go with a mild side can delete option keeping headers or if closer to out of warranty the Dundon catless headers.

3.8 and 4.0RS Dyno pulls with side muffler delete and M&M centers.
Both made more power as well:



The sound was great for me.

Jrtaylor9

I opened the valves: volume problem fixed. Not as loud in cabin as a 997 x-pipe setup but it's good enough that I doubt I change anything from here. The side delete is compelling but I'm probably too lazy to try it relative to the sound I got with RSS and opened valves.

rosenbergendo

GMG goes on my RS on Friday. Hoping for some big improvements!

gmgracing

You won't be disappointed! I will grab some decent pictures at the same time.


For posterity, I agree with Brosef. I have heard literally dozens of setups/combinations and my personal favorite is either a simple center section, or a combination of headers and center section (whilst retaining the stock side mufflers and sport button).

-Andrew

PhilT3 (PT3)

I had a manual override switch added to mine so I could use a remote to keep the valves open or closed full time. I love the ability to go from mild to wild.

TRAKCAR

^^ Phil, that was Fabspeed side muffler delete if I remember right?
You sent me some info once, I been slacking / waiting for the OEM's to crack..

Nine1won

I'd go GMG. I've found it is the loudest of the bypasses. My Barney is plenty loud!

DocMo

Glad it worked out nicely, could you please describe the sound volume and characteristics under 3000 rpm and above? I am mostly interested in the sound inside the cabin including upshift and downshift bangs.

I am asking as I plan on getting the RSS Xpipe for my upcoming 991.2 GT3 (yes already planning the first mods and which ceramic coating I'll get

bronson7

I should know this but I'm getting older and more forgetful each and everyday. When you say, "I opened the valves", could you please explain what you did? Thank you in advance.