alberthyc

Hi rennlister

Lets talk about your preference and experience on different aftermarket exhausts.

Personally my 991.1 gt3rs were previously fitted with SPMotorsports RSR Exhaust, straight pipe. Unfortunately it got too loud especially on start ups where neighbors and family members werent too happy. Subsequently i changed it to the Sharkwerks Sport Exhaust compatible to the factory value control. I keep my valve open constantly by pressing the valve button upon start up and on high revs, the pitch of the exhaust note is just nice. Nothing too loud and disturbing yet it is loud enough to make me feel driving a sport car/supercar.

However, i had issues on my last track days where my exhaust surround started to melt. This could be a fitment issue but my mechanic has yet to confirm this.

i am interested to know your experience and comments on other brands such as GMG, Dundon, JCR, Akrapovic, etc.

thank you

DDE997

I have a custom made TI center section, sounds great and not too loud.

silvertige

I have the sharkwerks with plugged valves. Pretty happy with it as its not ridiculously loud and doesn't have the weird sound transition between 2-3k. No drone, and great sound to my ears.

Seth Thomas

Dundon Headers with titanium center loud muffler. To me this is the perfect mix of sound, performance and something that is not too loud.

HRJ

I'm just running a FabSpeed CMD on my 991.2 GT3 6MT. Not obnoxious, but plenty loud above 4K and zero drone.

MKIVdan

I have the dundon crack pipe, Its glorious in sound but way too loud. I don't drive the car that often but longer trips to the track really take a toll on your ears with the drone.

No issue of melting or fitment, but I will say, the dundon crack pipe has a lot of metal vibration noises that drove me nuts and had to play whack a mole with to find and fix, also the clamps tend to break a lot due to vibration.

spyderbret

I have the IPE headers, cats and exhaust and it's pretty loud. The car spends most of it's time on track so it's not an issue but if I drove it more around town I would consider it to be almost too loud. For my use case, its' perfect.

CME

I have the Dundon Race Headers and their Quiet Muffler. The car is loud for my tastes but it’s not unbearable. I keep it on for the weight loss in the rear of the car as I do track a decent amount. The cold start is glorious and if you are worried about waking your neighbors, be aware.

I do a get a mild drone between 2-3k rpm so try and keep the car above 3k most times. Also get a drone and weird noises if using the rev match on the street. Have not figured out why that is happening but I rarely use that function.

chet

Meraki Autoworks

Our best sellers right now are Soul Performance followed by Akrapovic!

-Josh

Larry Cable

I have the Soul valved bypass with the OEM center, I may subsequently replace the center with either the Akrapovic Ti or the forthcoming Soul center ... but given the sound restrictions at N.Ca tracks Db is an issue.

I personally think losing the side mufflers is more bang for your $ than a center replacement, removing the sides take a a lot of weight off of the back of the car, and removes some large heat sources from the rear wheels and brakes ... and it improves the sound but not obnoxiously ...

race systems in N.Ca are just not an option if you want to run most of the tracks here - even the OEM setup on the 991.2 GT3 comes close to blowing sounds at Laguna Seca.

bogey1

I'm fortunate enough to be part of a group called Smokies GT. We have a couple functions every year here in the GA/NC mountains. We have had as many as 130 GT cars at events, and likely over 1,000 different GT cars over the years. I figure we have participants with just about every possible configuration. The crack pipes and JCR products are for guys that want LOUD, I mean LOUD. The Akro products are sound great and the build quality is beautiful. One of my buddies that comes up from MS/LA has the Soul products on his 997.2RS - sounds incredible. All kinds of different center mufflers, my personal favorite if only doing that would be the GMG. I was personally looking to gain some much needed torque and went the only direction I have seen proven results - Dundon. The combo of their headers, loud center (removing sides) and the intake/throttle body system makes a nice performance improvement and has the added bonus of sounding terrific. The bonus is getting great customer support from the guys at Dundon.

PCarOMFS

I have the non-valved Soul Performance SMB and CMB pipes. It’s very loud and sounds glorious. There is drone from 2-3k rpm but once traveling at around 70mph it disappears. My car is mainly a track car so it’s all good. If I took long trips in it I would do SMB and keep OEM center muffler or get the upcoming Soul center muffler. You can’t go wrong with Soul Performance. They’re top quality, great customer service, reasonably priced, and lifetime track and street warranty.

Xec

There's a lot of permutations possible with GT3 exhausts and I've tried to hear many in person. As most of you know, there are three sections of the GT3 exhausts that you can swap: headers, side mufflers, and center mufflers.

I'll try to provide a summary of my experience below, by increasing volume:

1. Side Muffler Delete: this is the tamest aftermarket configuration. After choosing between valved or no-valves, they all sound effectively the same regardless of brand and material. Great for track because the volume isn’t too bad, and it removes a ton of weight. Also removes a bunch of heat off the rear tires. Most of the GT cars I've seen on track run this setup. Any decently priced pair from a reputable manufacturer would work great.

2. Center Muffler Delete: this is a big step up in volume from SMDs. The volume and tone will vary greatly with design and material. Designs with expansion chambers (GMG, Soul, Dundon, etc) are significantly louder than those without (Sharkwerks, Akrapovic, JCR, etc). Titanium exhausts tend to have a more metallic timbre than those made with stainless steel. The difference between brands with the same design is minuscule (GMG and Soul sound nearly identical; Sharkwerks and Akrapovic sound nearly identical). The Dundon Mini Crack Pipe is easily the loudest center bypass (and also has the biggest megaphone design).

3. Headers + SMD: this assumes retaining the OEM center or an aftermarket center muffler (e.g. Dundon). The volume and tone varies greatly with design and material of the headers, and if you are catted or no cats. Most headers tend to be expensive ($5K and up). If I'm paying that much, I'd only consider Dundon. They have a true long tube design (inherently deletes the OEM side mufflers as the headers are rerouted to occupy that space) that offers real power gains. Paired with a center muffler, it's got a distinctively beefier tone that's different than that of catback configurations. In strict volume, this setup with a factory center is about as loud as quieter CMD above. An aftermarket center like Dundon's is about as loud as an expansion chamber CMD.
*I have not heard any Headers + CMD setup so I can't comment on that. Given the volume increase from a CMD, I'd probably guess it would result in a big volume difference between valves closed/open.

4. Center Delete + Side Delete: this is basically a catback straight pipe and is significantly more aggressive than anything above. Valves don't do much with this setup as all the mufflers have been deleted, so you're just rerouting gases through different sections of straight pipe. I have this setup and on my track day I couldn’t really hear my instructor even with race coms. Sounds epic though and I was the loudest car on track. Your choice of center delete makes the biggest difference in volume here. The Dundon Full Crack Pipe is the loudest version of this setup (comes with a side delete).
OP's SPM RSR exhaust is probably similar to this. I've heard the JCR Race Pipes, which is an all-in-one version of this catback straight pipe setup. It has a very distinctive high pitch at 6-9K RPM. It is quieter than catback straight pipes with an expansion chamber CMD, but still louder than any of the previous configurations mentioned above.

5. Headers + CMD + SMD: never heard this personally but a friend who has said it's 3x louder than my full Soul catback and was the loudest car he'd ever heard. Your ears and neighbors will hate you. When I get a RS, I plan on trying this setup LOL.
1. Side Muffler Bypass: this is

the tamest aftermarket configuration. They all sound the same regardless of brand and material. Great for track because the volume isn’t too bad, and it removes a ton of weight. Also removes a bunch of heat off the rear tires. At MSRC, all the GT cars I saw out there ran this setup.

Larry Cable

pretty much .1 is the best/only option if you want to track in N.Ca or your track has sound limits around 92+Db even the OEM setup can blow by 90Db...

twospyders

Manual 991.2 GT3:
I am doing DUNDON headers and center muffler along with their throttle body and airbox. Love the additional power and sound.