Dundon 321SS Lifetime Center Muffler for 997/991
07-14-2017, 12:24 AM
#32
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Join Date: Apr 2017
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Good work Jamie.
I'am waiting for the louder version.
It's stange to say but even with your raceheader fitted with the oem silencer, the car is too quiet for me.
I'am waiting for the louder version.
It's stange to say but even with your raceheader fitted with the oem silencer, the car is too quiet for me.
07-18-2017, 03:25 PM
#34
Instructor
I'm likely in - I don't care much about sound, but really don't like the idea of a very loud car attracting unwanted attention from the popo.
I have Fabspeed side can deletes - so quieter version for me, as long as no HP/Torque loss.
Did you guys mention weight vs stock center muffler? I saw your SS version was same as SS OEM. We have Titanium center muffler though right?
I have Fabspeed side can deletes - so quieter version for me, as long as no HP/Torque loss.
Did you guys mention weight vs stock center muffler? I saw your SS version was same as SS OEM. We have Titanium center muffler though right?
07-18-2017, 06:42 PM
#35
Can you provide some measurements of static noise as well, this is how it is measured on local tracks for both DE and licenced race cars:
4500rpm
0,5m and 45 degree angle from exhaust tips.
Most local tracks has a limit of 100dB measured this way, which is barely passed with a 997.1 GT3 (SW 3.9l) with side delete and OEM center exhaust.
Very interested if it reduce noise and has no drone even with side deletes, especially if flow is better than OEM.
Thx.
4500rpm
0,5m and 45 degree angle from exhaust tips.
Most local tracks has a limit of 100dB measured this way, which is barely passed with a 997.1 GT3 (SW 3.9l) with side delete and OEM center exhaust.
Very interested if it reduce noise and has no drone even with side deletes, especially if flow is better than OEM.
Thx.
Just finished some track side testing:
Conditions: Clear skies, 75F, 50ft measuring distance on the front straight
991 GT3 Dundon Race Headers (catless, w/ side deletes)
OEM Muffler: ~102dB
Ultra Quiet straight tips: ~92dB
So about a 10dB reduction. With Turn aways would likely be 3-4dB further reduction.
PLEASE DON"T TAKE THESE AS ABSOLUTE MEASUREMENTS. How sound levels are measured, weather conditions, tip orientation, etc... have a HUGE effect on the absolute number.
We have further testing to do on it, should have a loud version to play with at the end of the week.
Conditions: Clear skies, 75F, 50ft measuring distance on the front straight
991 GT3 Dundon Race Headers (catless, w/ side deletes)
OEM Muffler: ~102dB
Ultra Quiet straight tips: ~92dB
So about a 10dB reduction. With Turn aways would likely be 3-4dB further reduction.
PLEASE DON"T TAKE THESE AS ABSOLUTE MEASUREMENTS. How sound levels are measured, weather conditions, tip orientation, etc... have a HUGE effect on the absolute number.
We have further testing to do on it, should have a loud version to play with at the end of the week.
07-20-2017, 03:10 AM
#36
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I'm likely in - I don't care much about sound, but really don't like the idea of a very loud car attracting unwanted attention from the popo.
I have Fabspeed side can deletes - so quieter version for me, as long as no HP/Torque loss.
Did you guys mention weight vs stock center muffler? I saw your SS version was same as SS OEM. We have Titanium center muffler though right?
I have Fabspeed side can deletes - so quieter version for me, as long as no HP/Torque loss.
Did you guys mention weight vs stock center muffler? I saw your SS version was same as SS OEM. We have Titanium center muffler though right?
Can you provide some measurements of static noise as well, this is how it is measured on local tracks for both DE and licenced race cars:
4500rpm
0,5m and 45 degree angle from exhaust tips.
Most local tracks has a limit of 100dB measured this way, which is barely passed with a 997.1 GT3 (SW 3.9l) with side delete and OEM center exhaust.
Very interested if it reduce noise and has no drone even with side deletes, especially if flow is better than OEM.
Thx.
4500rpm
0,5m and 45 degree angle from exhaust tips.
Most local tracks has a limit of 100dB measured this way, which is barely passed with a 997.1 GT3 (SW 3.9l) with side delete and OEM center exhaust.
Very interested if it reduce noise and has no drone even with side deletes, especially if flow is better than OEM.
Thx.
Free revving at 4500rpm 0.5m and 45 degree angle?
__________________
Dundon Motorsports
Gig Harbor, WA
253-200-4454
jamie@dundonmotorsports.com
www.dundonmotorsports.com
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Dundon Motorsports
Gig Harbor, WA
253-200-4454
jamie@dundonmotorsports.com
www.dundonmotorsports.com
Facebook.com/dundonmotorsports
Instagram @dundon_motorsports
07-20-2017, 03:11 AM
#37
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You're part of the test pilot crew!
07-21-2017, 01:19 AM
#38
Instructor
So when might you guys be making them? I'm a bit unhappy with the volume increase of my side deletes. If it's quieter, then I'm happy, and I imagine a fair amount of others as well.
Not to mention decreasing track volume problems.
I want to be one of the cool kids who are in as well.
thanks
-Francis
Not to mention decreasing track volume problems.
I want to be one of the cool kids who are in as well.
thanks
-Francis
07-21-2017, 07:29 PM
#39
Rennlist Member
I could be in if it accepts OEM tips, and will pass Laguna Seca sound... 
07-23-2017, 06:44 PM
#40
Yes, we just bring the revs up slowly to 4500 rpm while the marshal holds the meter on a stick giving the correct distance and angle - or at least that is how it should be done.
Most of the time they just wing it while we cheat with the revs, but thats another story :-D.
The interesting thing is of course the difference in noise between OEM exhaust and yours, and this method is very easy for testing purposes.
Most of the time they just wing it while we cheat with the revs, but thats another story :-D.
The interesting thing is of course the difference in noise between OEM exhaust and yours, and this method is very easy for testing purposes.
07-23-2017, 11:10 PM
#41
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Yes, we just bring the revs up slowly to 4500 rpm while the marshal holds the meter on a stick giving the correct distance and angle - or at least that is how it should be done.
Most of the time they just wing it while we cheat with the revs, but thats another story :-D.
The interesting thing is of course the difference in noise between OEM exhaust and yours, and this method is very easy for testing purposes.
Most of the time they just wing it while we cheat with the revs, but thats another story :-D.
The interesting thing is of course the difference in noise between OEM exhaust and yours, and this method is very easy for testing purposes.
07-26-2017, 12:46 AM
#42
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"Loud" Center muffler finishing up fab work this week, and the 2nd quiet muffler will be heading to BR Racing next week for one of their customers. We'll have two Quiet prototypes being torture tested at Laguna on the 4th of August. One on a 991 GT3 with Side Muffler Deletes, and one on a 997.2 GT3
07-26-2017, 12:30 PM
#43
Rennlist Member
"Loud" Center muffler finishing up fab work this week, and the 2nd quiet muffler will be heading to BR Racing next week for one of their customers. We'll have two Quiet prototypes being torture tested at Laguna on the 4th of August. One on a 991 GT3 with Side Muffler Deletes, and one on a 997.2 GT3
07-26-2017, 06:16 PM
#44
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OH no.
Please do not misunderstand me: Sound is good and I really like it. It's perfectly balanced and perfectly streetable.
I don't want more sound à low rpm.
I would like to keep it as quiet as possible at low speed and more loud at WOT and high range rpm.
What are your lound version catacteristics?
Will it be loud everytime or just at wot?
07-26-2017, 06:53 PM
#45
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OH no.
Please do not misunderstand me: Sound is good and I really like it. It's perfectly balanced and perfectly streetable.
I don't want more sound à low rpm.
I would like to keep it as quiet as possible at low speed and more loud at WOT and high range rpm.
What are your lound version catacteristics?
Will it be loud everytime or just at wot?
Please do not misunderstand me: Sound is good and I really like it. It's perfectly balanced and perfectly streetable.
I don't want more sound à low rpm.
I would like to keep it as quiet as possible at low speed and more loud at WOT and high range rpm.
What are your lound version catacteristics?
Will it be loud everytime or just at wot?