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Dundon 321SS Lifetime Center Muffler: 991.1/991.2 GT3 RS and 911R Intro Buy Is Open
Most of us have experienced the many issues associated with both the stock Steel and Ti rear mufflers on our beloved 997.1, 997.2 , 991.1 and 991.2 GT3, GT3RS and 911R. cracking, holes, not passing sound etc... We've been reinforcing both the Steel and Ti versions for years after they crack and understand why they fail quite well. We set out to fix the weakness of the OEM center muffler and include an option for those that want their car to pass the more and more prevalent dB restricted tracks without losing power. We finalized the design and have tested at numerous tracks both for longevity and for dB reduction.
Prevent this from happening to you!
Cracked Ti Rear Muffler
We're happy to officially announce our 321SS Lifetime Center Muffler for the 997.1 and 997.2 GT3/RS is available. We've made it in 2 versions "Black" (louder than OEM) and "Orange" (quieter than OEM). We're putting together 50 pcs in total for the first batch, 20 or so have been pre sold. We expect delivery to begin by early November (all parts are in production now).
"Black" (Loud) 321SS Lifetime Center Muffler
321 Stainless Steel with reinforcing gussets and stitch plates for a lifetime of track use.
Larger Diameter tubing than OEM supporting higher HP build (up to 600 hp without restriction).
Sound Levels equivalent to a center delete without power loss (banks have a long merge)
No drone when used with valved side muffler deletes
4” Slashed Black Tips with mounting adjustment (in case you don’t get the muffler exactly centered)
Turnaway Tips available, easy swap with 3 bolts.
"Orange" (Quiet) 321SS Lifetime Center Muffler
321 Stainless Steel with reinforcing gussets and stitch plates for a lifetime of track use.
Sound reducing design, allowed 997.1 with side deletes and 997.2 with stock side mufflers to pass sound at Laguna without an GPS flap devices*
No loss in HP/TQ.
Our testing shows 10-12dB reduction over the OEM muffler*
No drone when used with valved side muffler deletes
4” Slashed Black Tips with mounting adjustment (in case you don’t get the muffler exactly centered)
Turnaway Tips available, easy swap with 3 bolts.
*dB reduction is our measurement not an absolute measurement, the Orange mufflers have been tested independently by 3 991 GT3's and 2 997 GT3's with various configurations of exhaust. All have passed at Laguna. This isn't a guarantee that others will pass.
4" Slashed Tips on 991 GT3 (tips will be 1/2" longer on production units, and Muffler will sit a little higher in the car). Hardware provided will be Black as well.
4" Slashed Tips and Tip Plate (turnaways bolt to the tip plate as well)
4" Slashed Tips and Tip Plate (turnaways bolt to the tip plate as well)
Reinforcing Stitch Plate
Under Skirt Shot (Tubing will be flush with the Tip plate on production versions)
Tip Plate (Tubing will be flush with Tip Plate on production versions)
This is a totally honest and not an incendiary question, but why do these center mufflers look so bad? Welds aren't even, I don't understand why there are bits that are open (reinforcements?), and why does it look so banged up?
What's the increase in DB from the black muffler center vs OEM?
This is a totally honest and not an incendiary question, but why do these center mufflers look so bad? Welds aren't even, I don't understand why there are bits that are open (reinforcements?), and why does it look so banged up?
What's the increase in DB from the black muffler center vs OEM?
Originally Posted by RennOracle
This is a totally honest and not an incendiary question, but why do these center mufflers look so bad? Welds aren't even, I don't understand why there are bits that are open (reinforcements?), and why does it look so banged up?
What's the increase in DB from the black muffler center vs OEM?
Thanks for your question, I think you're not the only one wondering this.
First, I think people in general have grown used to seeing welds that are "polished" afterward so that there is no heat signature remaining color wise to understand the quality of the weld. The "rainbow" welds that everyone sees and are enamored by are actually poor torch control as the color is from the oxides that grow on the metal due to varying temperature. Varying temperature creates varying stresses in the metal and a weaker overall weld. Completely silver welds the same color as the rest of the metal means likely that the muffler has been polished after welding... Don't get me wrong there are some that do wonderful welds, but anytime you see a product polished to a mirror finish after welding you less ways of seeing the quality of the welds.
Now to your specific questions.
1. This is a prototype, the finished product will have a more consistent appearance.
2. The tabs and slots we are using to construct and reinforce the muffler, locking it together, are what is poking through and make it look "beat up". These are fused (tabs melted with a torch and fused to the plate) for the ultimate in strength, not welded with rod. The consistent golden color at the fused tab is what you're looking for to show a consistent amount of heat. The fact that there are golden areas and non golden areas makes the muffler look "beat up".
3. The open areas on the front in line with the tips is a reinforcement plate over one of the seems, further working to make the muffler bullet proof
4. dB increase of Loud vs OEM from our testing is about 10dB at wide open throttle, it also has a bit higher pitch due to the 3" diameter internals and design of the merge.
I'm just glad that you have a "quiet" option.....with all the tracks clamping down on sound emissions, you have the only product that answers this need!
So, the loud version is comparable to a center bypass when valve is open? And how about the sound and noise-level when the valves are closed (with side delete / long tube headers)? 991.1 GT3.
Jamie, do you have a video of Orange with race or catted headers with side deletes? What is the db difference in Orange and black with valves open and closed? Thank you!
Jamie, do you have a video of Orange with race or catted headers with side deletes? What is the db difference in Orange and black with valves open and closed? Thank you!
I have Orange with and race headers on my car now, also the testing we did with the Orange was with race headers at the Ridge that was 10-12dB less than the OEM muffler. Didn't get dB with valves closed as I don't run a GPS valve box in my car. Difference between Orange and Black with Valves open at full throttle is in the 20dB range. OEM being the center, Black is about 10dB louder and Orange is about 10-12dB less...
So, the loud version is comparable to a center bypass when valve is open? And how about the sound and noise-level when the valves are closed (with side delete / long tube headers)? 991.1 GT3.
The Loud version is still not as loud as a center bypass as it's still a muffler (there is an expansion so the pressure is reduced). Center delete with Race headers and side deletes is LOUD LOUD LOUD! With the valves closed the Black is still very docile, drive it on the street and have a phone conversation in the car with no issue and no drone...
Thanks Jamie. I currently use the fvd center bypass and have a switch to permanently open the valves.
When we compare this to your catted long tube headers and the Loud version of your center muffler: what would you expect (in terms of db and quality of sound) in case of:
-> valves forced permanentely closed / gps
-> valve controll stock
-> valves forced permanentely open
?
Great stuff!
How quiet are the street headers/exhaust compared to stock? I track at a track that is limited to 92db at 50' measured at 2 places on track. Some stock 991 GT3's, RS's and even GT4's pop sound with the valve open...on stock systems.
What are the chances i stay under the limit?
So, the loud version is comparable to a center bypass when valve is open? And how about the sound and noise-level when the valves are closed (with side delete / long tube headers)? 991.1 GT3.
Originally Posted by Cay_PI
Thanks Jamie. I currently use the fvd center bypass and have a switch to permanently open the valves.
When we compare this to your catted long tube headers and the Loud version of your center muffler: what would you expect (in terms of db and quality of sound) in case of:
-> valves forced permanentely closed / gps
-> valve controll stock
-> valves forced permanentely open
?Thanks.
The Loud muffler with GPS closed valves will be a bit louder than stock as the muffler has larger tubing
The Loud muffler with normal valves will not drone, would be quieter at idle vs your current setup with valves open, no drone and a nice flat six wail when the valves are open
The Loud Muffler with valves open all the time would be about the same as your bypass with valves open, could possibly drone a bit between 2500-3000rpm (where the factory program closes the valves).
With the street headers added to the above would take everything up a bit on the dB scale as the Dundon Street headers increase cylinder pressure (produce more power) and the resulting pressure wave coming out of the exhaust valve is stronger (higher pressure is higher dB). All of the above is true when the car is under power, when your idling and cruising around the catted system is very close to stock with a side muffler delete.
Originally Posted by Chris R.
Great stuff!
How quiet are the street headers/exhaust compared to stock? I track at a track that is limited to 92db at 50' measured at 2 places on track. Some stock 991 GT3's, RS's and even GT4's pop sound with the valve open...on stock systems.
What are the chances i stay under the limit?
If you're trying to reach sound restrictions, I'd start with just an Orange muffler and see how it goes. We have good luck at Laguna (90dB) with both 991 and 997 cars with stock exhaust systems and with side muffler deletes passing with our Orange Muffler.
The Street headers and side deletes are similar to the stock car with side deletes, but I'd want to see where your car is first with just the muffler, since getting black flagged for sound is no fun...
09-24-2017, 10:30 PM
Dundon 321SS Lifetime Center Muffler: 991.1/991.2 GT3 RS and 911R Intro Buy Is Open
