Sound limits?
12-04-2015, 12:20 PM
#1
Melting Slicks
Pro Mechanic
Thread Starter
Member Since: Nov 2013
Location: Ex DPRK, now just N of Medford, OR
Posts: 2,914
Received 735 Likes
on
545 Posts
Sound limits?
C6Z...
Thinking of doing some NCRC Laguna dates in 2016... but they're all 90 db.
Has anyone gotten down to that? And how?!
Right now I have catted headers and stock mufflers. I wrapped the headers to try and damp out the ringing, and was thinking about turndowns and wiring the exhaust control for manual operation past the sound station.
Any thoughts or suggestions?
Thanks!
Thinking of doing some NCRC Laguna dates in 2016... but they're all 90 db.
Has anyone gotten down to that? And how?!
Right now I have catted headers and stock mufflers. I wrapped the headers to try and damp out the ringing, and was thinking about turndowns and wiring the exhaust control for manual operation past the sound station.
Any thoughts or suggestions?
Thanks!
Last edited by Nowanker; 12-04-2015 at 12:54 PM.
The following users liked this post:
Nowanker (12-05-2015)
12-05-2015, 02:23 PM
#4
Melting Slicks
Pro Mechanic
Thread Starter
Member Since: Nov 2013
Location: Ex DPRK, now just N of Medford, OR
Posts: 2,914
Received 735 Likes
on
545 Posts
NCRC has a bunch of modestly priced dates coming up, but I'd hate to sign up and get thrown out after 3 laps!
12-09-2015, 01:45 PM
#5
Burning Brakes
this worked for me
C6Z...
Thinking of doing some NCRC Laguna dates in 2016... but they're all 90 db.
Has anyone gotten down to that? And how?!
Right now I have catted headers and stock mufflers. I wrapped the headers to try and damp out the ringing, and was thinking about turndowns and wiring the exhaust control for manual operation past the sound station.
Any thoughts or suggestions?
Thanks!
Thinking of doing some NCRC Laguna dates in 2016... but they're all 90 db.
Has anyone gotten down to that? And how?!
Right now I have catted headers and stock mufflers. I wrapped the headers to try and damp out the ringing, and was thinking about turndowns and wiring the exhaust control for manual operation past the sound station.
Any thoughts or suggestions?
Thanks!
By the way, my LS3 had a cold air intake, Z06 exhaust manifold,
Z06 cats, Z06 H pipe and C6 NPP exhaust tips. This combination is louder than a conventional C6.
Hope this helps. Good luck
The following users liked this post:
Nowanker (12-09-2015)
12-09-2015, 03:07 PM
#6
Have not drove there in about 10 years but the sound check station was in a yellow shack between turns 5&6.It was on the rh side.The guys with mazda rotorys would hang a 90 degree bend and another muffler pointing left away from the shack.They might be running around with a hand held meter now.
12-09-2015, 03:40 PM
#7
Melting Slicks
Pro Mechanic
Thread Starter
Member Since: Nov 2013
Location: Ex DPRK, now just N of Medford, OR
Posts: 2,914
Received 735 Likes
on
545 Posts
Interesting thought about pointing the turn downs at 10:00. Never occurred to me, but might make sense to have it dissipate into the air, pointed away from the sound booth, rather than echoing off the pavement.
Been a couple of years since I was there, and far as I know the sound station is still in the same place... but on occasion they have had a hand held guy sneaking around.
Been a couple of years since I was there, and far as I know the sound station is still in the same place... but on occasion they have had a hand held guy sneaking around.
12-15-2015, 09:03 PM
#8
Burning Brakes
12-16-2015, 01:06 AM
#9
In stock form, my 07z measured 92.2 at Laguna......of course, they meatballed me during that 92db day. I spent the rest of the day short shifting.
When the 90db days rolled around, I knew I had to do something more drastic. I ended up using the flap system in my stock bi-mode exhaust system by installing a switch that routes either the normal computer control output or a custom output to the exhaust solenoids. The custom output is a second switch on the stock shift handle (from LG) that outputs either 12v or 0v, essentially forcing the flaps shut or open. This allows me to switch to quiet mode when downshifting for T5 (approaching sound station). When past the sound station, I switch back to open (loud) mode, and I can feel the little extra kick when the exhaust opens up on that uphill section between T5 and T8. With the switch in the shift ****, I can use my thumb to control the flaps without hunting for a switch and/or taking my eyes from the track.
So far it has worked for four 90db days in varying conditions.
When the 90db days rolled around, I knew I had to do something more drastic. I ended up using the flap system in my stock bi-mode exhaust system by installing a switch that routes either the normal computer control output or a custom output to the exhaust solenoids. The custom output is a second switch on the stock shift handle (from LG) that outputs either 12v or 0v, essentially forcing the flaps shut or open. This allows me to switch to quiet mode when downshifting for T5 (approaching sound station). When past the sound station, I switch back to open (loud) mode, and I can feel the little extra kick when the exhaust opens up on that uphill section between T5 and T8. With the switch in the shift ****, I can use my thumb to control the flaps without hunting for a switch and/or taking my eyes from the track.
So far it has worked for four 90db days in varying conditions.
The following users liked this post:
Nowanker (12-16-2015)
12-16-2015, 09:53 AM
#10
Melting Slicks
Pro Mechanic
Thread Starter
Member Since: Nov 2013
Location: Ex DPRK, now just N of Medford, OR
Posts: 2,914
Received 735 Likes
on
545 Posts
I'll see you out there. We actually met down at Buttonwillow about a year ago, I had (still have...) a blue C5. Moved up to a C6Z, looking forward to some track time.
Steve
12-16-2015, 09:57 AM
#11
Melting Slicks
Pro Mechanic
Thread Starter
Member Since: Nov 2013
Location: Ex DPRK, now just N of Medford, OR
Posts: 2,914
Received 735 Likes
on
545 Posts
In stock form, my 07z measured 92.2 at Laguna......of course, they meatballed me during that 92db day. I spent the rest of the day short shifting.
When the 90db days rolled around, I knew I had to do something more drastic. I ended up using the flap system in my stock bi-mode exhaust system by installing a switch that routes either the normal computer control output or a custom output to the exhaust solenoids. The custom output is a second switch on the stock shift handle (from LG) that outputs either 12v or 0v, essentially forcing the flaps shut or open. This allows me to switch to quiet mode when downshifting for T5 (approaching sound station). When past the sound station, I switch back to open (loud) mode, and I can feel the little extra kick when the exhaust opens up on that uphill section between T5 and T8. With the switch in the shift ****, I can use my thumb to control the flaps without hunting for a switch and/or taking my eyes from the track.
So far it has worked for four 90db days in varying conditions.
When the 90db days rolled around, I knew I had to do something more drastic. I ended up using the flap system in my stock bi-mode exhaust system by installing a switch that routes either the normal computer control output or a custom output to the exhaust solenoids. The custom output is a second switch on the stock shift handle (from LG) that outputs either 12v or 0v, essentially forcing the flaps shut or open. This allows me to switch to quiet mode when downshifting for T5 (approaching sound station). When past the sound station, I switch back to open (loud) mode, and I can feel the little extra kick when the exhaust opens up on that uphill section between T5 and T8. With the switch in the shift ****, I can use my thumb to control the flaps without hunting for a switch and/or taking my eyes from the track.
So far it has worked for four 90db days in varying conditions.
That's the info I was looking for! I was planning to try that approach, but wasn't sure if it'd do the trick. I might bring some turndowns with me just in case...
12-16-2015, 11:39 AM
#12
Drifting
Member Since: Nov 2006
Location: Sierra Mtns. The Great State Of Jefferson
Posts: 1,810
Received 169 Likes
on
128 Posts
In stock form, my 07z measured 92.2 at Laguna......of course, they meatballed me during that 92db day. I spent the rest of the day short shifting.
When the 90db days rolled around, I knew I had to do something more drastic. I ended up using the flap system in my stock bi-mode exhaust system by installing a switch that routes either the normal computer control output or a custom output to the exhaust solenoids. The custom output is a second switch on the stock shift handle (from LG) that outputs either 12v or 0v, essentially forcing the flaps shut or open. This allows me to switch to quiet mode when downshifting for T5 (approaching sound station). When past the sound station, I switch back to open (loud) mode, and I can feel the little extra kick when the exhaust opens up on that uphill section between T5 and T8. With the switch in the shift ****, I can use my thumb to control the flaps without hunting for a switch and/or taking my eyes from the track.
So far it has worked for four 90db days in varying conditions.
When the 90db days rolled around, I knew I had to do something more drastic. I ended up using the flap system in my stock bi-mode exhaust system by installing a switch that routes either the normal computer control output or a custom output to the exhaust solenoids. The custom output is a second switch on the stock shift handle (from LG) that outputs either 12v or 0v, essentially forcing the flaps shut or open. This allows me to switch to quiet mode when downshifting for T5 (approaching sound station). When past the sound station, I switch back to open (loud) mode, and I can feel the little extra kick when the exhaust opens up on that uphill section between T5 and T8. With the switch in the shift ****, I can use my thumb to control the flaps without hunting for a switch and/or taking my eyes from the track.
So far it has worked for four 90db days in varying conditions.
12-16-2015, 01:02 PM
#13
I published a detailed writeup on 12/28/2012 under the title "Homebrew Exhaust Control (long)", but here it is again............
At my last Laguna track day, it turned out to be a 90db (!) day. Turns out the locals are winning the noise battle and it appears many Laguna days from here on will be 90db ones. I flunked during my last session (92.2db) in my stock C6Z, so I decided I needed a bolt-on exhaust diverter like so many others do. However, I did not want to damage my exhaust tips, but the more I looked into it, the more it seemed difficult and expensive, and jerry rigged at best.
So I decided to use the stock exhaust valve system in my z (I'm assuming that it will be quiet enough with the valves closed). I had some mini spdt toggle switches around and plenty of wire and had previously purchased an add-a-circuit and an LG exhaust valve harness with the switch in the shift ****. The idea was to cut the 12v feed to the exhaust solenoid and use the spdt toggle to switch the solenoid to connect to either the exhaust control module (stock config) or to 12v (controlled by the shift **** switch). This way I could close the exhaust valves when passing the sound shack at T5 exit and leave them open during the rest of the lap.
I also decided while I was wiring things up to install another toggle switch to control my AMB transponder.
I took my time, and it got it done in three days (a few hours each day) despite a few surprises. The exhaust control module was not where I thought it was. Some previous posts indicated it was behind the passenger side rear side carpet, but it was in the battery compartment. Also, I assumed that once I removed the tombstone there would be plenty of room to run wires and connectors, but there is a big piece of foam that surrounds the cup holder and part of the shift area. I had to pull out the center console to get enough room to run the shift **** connector to the tombstone cavity. Also, I decided not to use the usual exhaust module fuse location for 12v since I did not want to worry about the constant power with ignition off. The seat heater did not work because the add-a-circuit would not fit right side up (more on that later). I was surprised that most of the 10A fuse locations are powered with ignition off. I finally decided to use the cruise control fuse location; it is a 2A location, but assumed that all the wires are the same size to the fuse panel so there should be no issues with the small additional load of the solenoid.
I ran the wires from the exhaust controller in the back along the passenger side rear speaker, down the back carpet and along the central console to the tombstone cavity. The wires from the fuse panel I ran under the "hockey puck" trim piece, under the cup holder cover, and into the tombstone cavity.
It turned out the trickiest wire run was running a ground wire from the engine compartment to the console. I could not find a suitable entry point so I ran the wire along the bottom windshield trim, under the A pillar, under the door forward opening trim, then under the passenger kick panel into car. After that it followed the 12V run from the fuse panel.
I soldered all connections and used shrink tubing for protection. For the exhaust control module harness mods I used crimp connectors so that the harness could be easily returned to stock. After soldering the switches up I fired it up and everything worked. I then put all the panels back on and cleaned up......can't wait to try it on the track!
BTW, the earlier comment I made about the add-a-circuit being right side up or upside down.............when I checked out the fuse panel, all the circuit locations had the right fuse terminal being hot. This meant that if the add-a-circuit was installed right side up (fuses up or the red lead on the left), then both fuses were protecting their respective circuits. However, if the add-a-fuse was installed upside down (red lead to the right), then the "new" circuit is now dependent on the original fuse. Not a big deal, especially if both fuses are the same size, but I just wanted both to be independent so I went with a different location.
At my last Laguna track day, it turned out to be a 90db (!) day. Turns out the locals are winning the noise battle and it appears many Laguna days from here on will be 90db ones. I flunked during my last session (92.2db) in my stock C6Z, so I decided I needed a bolt-on exhaust diverter like so many others do. However, I did not want to damage my exhaust tips, but the more I looked into it, the more it seemed difficult and expensive, and jerry rigged at best.
So I decided to use the stock exhaust valve system in my z (I'm assuming that it will be quiet enough with the valves closed). I had some mini spdt toggle switches around and plenty of wire and had previously purchased an add-a-circuit and an LG exhaust valve harness with the switch in the shift ****. The idea was to cut the 12v feed to the exhaust solenoid and use the spdt toggle to switch the solenoid to connect to either the exhaust control module (stock config) or to 12v (controlled by the shift **** switch). This way I could close the exhaust valves when passing the sound shack at T5 exit and leave them open during the rest of the lap.
I also decided while I was wiring things up to install another toggle switch to control my AMB transponder.
I took my time, and it got it done in three days (a few hours each day) despite a few surprises. The exhaust control module was not where I thought it was. Some previous posts indicated it was behind the passenger side rear side carpet, but it was in the battery compartment. Also, I assumed that once I removed the tombstone there would be plenty of room to run wires and connectors, but there is a big piece of foam that surrounds the cup holder and part of the shift area. I had to pull out the center console to get enough room to run the shift **** connector to the tombstone cavity. Also, I decided not to use the usual exhaust module fuse location for 12v since I did not want to worry about the constant power with ignition off. The seat heater did not work because the add-a-circuit would not fit right side up (more on that later). I was surprised that most of the 10A fuse locations are powered with ignition off. I finally decided to use the cruise control fuse location; it is a 2A location, but assumed that all the wires are the same size to the fuse panel so there should be no issues with the small additional load of the solenoid.
I ran the wires from the exhaust controller in the back along the passenger side rear speaker, down the back carpet and along the central console to the tombstone cavity. The wires from the fuse panel I ran under the "hockey puck" trim piece, under the cup holder cover, and into the tombstone cavity.
It turned out the trickiest wire run was running a ground wire from the engine compartment to the console. I could not find a suitable entry point so I ran the wire along the bottom windshield trim, under the A pillar, under the door forward opening trim, then under the passenger kick panel into car. After that it followed the 12V run from the fuse panel.
I soldered all connections and used shrink tubing for protection. For the exhaust control module harness mods I used crimp connectors so that the harness could be easily returned to stock. After soldering the switches up I fired it up and everything worked. I then put all the panels back on and cleaned up......can't wait to try it on the track!
BTW, the earlier comment I made about the add-a-circuit being right side up or upside down.............when I checked out the fuse panel, all the circuit locations had the right fuse terminal being hot. This meant that if the add-a-circuit was installed right side up (fuses up or the red lead on the left), then both fuses were protecting their respective circuits. However, if the add-a-fuse was installed upside down (red lead to the right), then the "new" circuit is now dependent on the original fuse. Not a big deal, especially if both fuses are the same size, but I just wanted both to be independent so I went with a different location.
The following users liked this post:
moose.b3 (12-17-2015)