GT3 exhaust setup to reduce sound (Laguna!)
08-05-2018, 08:34 PM
#1
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Thread Starter
GT3 exhaust setup to reduce sound (Laguna!)
Read more than I can digest on options and variations... what setup do you all have when trying to reduce decibels while still sounding good?
Right now I have stock headers/cats/side mufflers and a BBI center section. Sounds amazing.. but loud at 103+db. Stuck on which center/side muffler combo to go with. Some of the options out there:
OEM/stock center section
Dundon quiet lifetime center muffler
Dondon side muffler deletes
Fabspeed mini maxflo center section replacement
Turn-away/Laguna pipes (not sure who makes these now?)
GPS valve close (not sure if these still exist?)
Tubi/Kline/iPe etc
Interested in what combo you drive and what decibel you can achieve? I'm assuming all the center section deletes (sharkwerks, fabseep, tubi etc) all have similar decibel ratings.
Thanks
Matty
Right now I have stock headers/cats/side mufflers and a BBI center section. Sounds amazing.. but loud at 103+db. Stuck on which center/side muffler combo to go with. Some of the options out there:
OEM/stock center section
Dundon quiet lifetime center muffler
Dondon side muffler deletes
Fabspeed mini maxflo center section replacement
Turn-away/Laguna pipes (not sure who makes these now?)
GPS valve close (not sure if these still exist?)
Tubi/Kline/iPe etc
Interested in what combo you drive and what decibel you can achieve? I'm assuming all the center section deletes (sharkwerks, fabseep, tubi etc) all have similar decibel ratings.
Thanks
Matty
08-05-2018, 10:23 PM
#2
Rennlist Member
Was actually speaking to someone today regarding this. They told me they simply lift off the throttle as they approach and pass the decibel meter. Obviously not feasible if you're chasing lap times. And as far as I know, the GPS valve close still exists (I was told around $800).
08-05-2018, 11:12 PM
#3
GT3 player par excellence
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^ whomever u talked to is either EXTREMELY slow or he got lucky.
if u just lift throttle u will pass. but the tower will figure it out. you will get caught.
GPS works
turn pipes works some of the time
that's about it.
if u just lift throttle u will pass. but the tower will figure it out. you will get caught.
GPS works
turn pipes works some of the time
that's about it.
08-05-2018, 11:46 PM
#4
Rennlist Member
Thread Starter
Mooty - are you saying that stock exhaust and/or Dundon “quiet” mufflers aren’t even quiet enough?
if yes.. these sound restrictions are even worse than I thought!
if yes.. these sound restrictions are even worse than I thought!
08-06-2018, 03:53 AM
#6
Banned
lifting didn’t work for me...still got dinged for 98db lifting to half throttle and a gear high. My car has aftermarket headers, side muffler delete and stock center.
when I had a gmg center bypass, stock header and stock side muffler, I passed sound once by forcing the valves closed using a vacuum cap on the exhaust pressure switch. Not the best way to do it though due to the heat build up in the cats from keeping the valves closed the whole time.
08-06-2018, 12:59 PM
#7
Read more than I can digest on options and variations... what setup do you all have when trying to reduce decibels while still sounding good?
Right now I have stock headers/cats/side mufflers and a BBI center section. Sounds amazing.. but loud at 103+db. Stuck on which center/side muffler combo to go with. Some of the options out there:
OEM/stock center section
Dundon quiet lifetime center muffler
Dondon side muffler deletes
Fabspeed mini maxflo center section replacement
Turn-away/Laguna pipes (not sure who makes these now?)
GPS valve close (not sure if these still exist?)
Tubi/Kline/iPe etc
Interested in what combo you drive and what decibel you can achieve? I'm assuming all the center section deletes (sharkwerks, fabseep, tubi etc) all have similar decibel ratings.
Thanks
Matty
Right now I have stock headers/cats/side mufflers and a BBI center section. Sounds amazing.. but loud at 103+db. Stuck on which center/side muffler combo to go with. Some of the options out there:
OEM/stock center section
Dundon quiet lifetime center muffler
Dondon side muffler deletes
Fabspeed mini maxflo center section replacement
Turn-away/Laguna pipes (not sure who makes these now?)
GPS valve close (not sure if these still exist?)
Tubi/Kline/iPe etc
Interested in what combo you drive and what decibel you can achieve? I'm assuming all the center section deletes (sharkwerks, fabseep, tubi etc) all have similar decibel ratings.
Thanks
Matty
Dundon quiet center also passes but then your car is quiet all the time. Since you live here you must find a way to pass sound at Laguna, otherwise it is just frustrating
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08-07-2018, 01:45 AM
#8
Rennlist Member
Thread Starter
Adi - do your side deletes maintain the valves or did you go with straight through sacrificing the valves?
In a perfect world I would like similar to you: side delete (with valves) for the weight and heat reduction.. and then a stock/other center muffler to manage decibels with turn down pipes if needed.
The BBI center section has integrated tips so normal turn down pipes may not work. I’m open to swapping any of the components, but reluctant to spend a bunch to find it not work correctly.
I also see fabspeed now have turn down tip replacements. Two sizes, can either replace stock tips, or a size that fits the fabspeed center section.
In a perfect world I would like similar to you: side delete (with valves) for the weight and heat reduction.. and then a stock/other center muffler to manage decibels with turn down pipes if needed.
The BBI center section has integrated tips so normal turn down pipes may not work. I’m open to swapping any of the components, but reluctant to spend a bunch to find it not work correctly.
I also see fabspeed now have turn down tip replacements. Two sizes, can either replace stock tips, or a size that fits the fabspeed center section.
08-07-2018, 01:52 AM
#9
Adi - do your side deletes maintain the valves or did you go with straight through sacrificing the valves?
In a perfect world I would like similar to you: side delete (with valves) for the weight and heat reduction.. and then a stock/other center muffler to manage decibels with turn down pipes if needed.
The BBI center section has integrated tips so normal turn down pipes may not work. I’m open to swapping any of the components, but reluctant to spend a bunch to find it not work correctly.
I also see fabspeed now have turn down tip replacements. Two sizes, can either replace stock tips, or a size that fits the fabspeed center section.
In a perfect world I would like similar to you: side delete (with valves) for the weight and heat reduction.. and then a stock/other center muffler to manage decibels with turn down pipes if needed.
The BBI center section has integrated tips so normal turn down pipes may not work. I’m open to swapping any of the components, but reluctant to spend a bunch to find it not work correctly.
I also see fabspeed now have turn down tip replacements. Two sizes, can either replace stock tips, or a size that fits the fabspeed center section.
I used the TPC side delete with the flaps, as those are necessary for the right sound reduction (straight cup or BBI side deletes won't work). If you are primarily focused on tracking then that is the setup to have as less weight and less heat trumps everything else. On my setup I have 200 cell cats, side deletes and RS titanium center. Car sounds good enough but performance well.
If you want to keep your stock as is, I have my old sharkwerks bypass if you want to try it out as you can interchange the tips. Either way no setup will work without the gps box to close the walves, as that is the biggest reduction available.
I would definitely get that figured out so you can fully enjoy Laguna
08-07-2018, 02:20 AM
#10
Rennlist Member
Thread Starter
As it stands I have no chance at Laguna.. in fact I breached the Thunderhill sound limit last time there (I didn’t think that was possible with my setup!)
Thanks for all the ideas.. since the gps valve close is non-negotiable i will reach out to Alek as a starting point.
Matty
Thanks for all the ideas.. since the gps valve close is non-negotiable i will reach out to Alek as a starting point.
Matty
08-07-2018, 02:41 AM
#11
Banned
As it stands I have no chance at Laguna.. in fact I breached the Thunderhill sound limit last time there (I didn’t think that was possible with my setup!)
Thanks for all the ideas.. since the gps valve close is non-negotiable i will reach out to Alek as a starting point.
Matty
Thanks for all the ideas.. since the gps valve close is non-negotiable i will reach out to Alek as a starting point.
Matty
08-11-2018, 10:24 PM
#12
Dundon muffler with turn ups absolutely works for 92 DB at Laguna Seca. It's been tested and works on stock 991 GT3/RS exhaust systems. if you have side muffler deletes, you may have issues as I don't think that combination has been tested. There is a NorCal shop that will let you rent the Dundon Orange if you want to try it.
Hit Jamie up at Dundon for details.
08-12-2018, 06:10 PM
#13
Rennlist Member
Thread Starter
Thanks for this. I am going to go with Adi’s setup I think: valved side muffler deletes with the Alekshop GPS valve closer (remove heat and weight) and a stock center section.
08-13-2018, 06:07 PM
#14
Regarding Laguna, is the consensus that center bypass + turn away tips will not be enough for <90-92dB?
08-13-2018, 06:11 PM
#15
At Laguna, just having turn down pipes reduces sound by 2-3 DBs, meaning if default is a 103, you are down to 100 or so. You can also stick to the left side of the track and reduce another 1-2 DB for sure. I am thinking of just generic turn down pipes. Cup cars and other folks have had turn down pipes that were packed with material and those worked fine, but are significantly larger, heavier and more expensive to setup. Just some thoughts...