Silencing the Beast

CountryTom · 10-30-2017, 11:33 PM

Hey all,

First off, sorry if this is out there but I tried search first.

Has anyone fabricated a clip that holds the muffler closed? Or better yet - a GPS-based valve device like this for Porsche? (https://rennlist.com/forums/991-gt3-...nd-checks.html)

Had Laguna Seca yesterday and blew sound 2x while severely lifting past the sound booth. (97 dB both times. But very low fog) Laguna pipes will help on a clear day but not in fog. Just researching for now and may settle on the Laguna Pipes in the end. Appreciate the insights

Thx!

travislambert · 10-31-2017, 09:14 AM

I assume the exhaust valve mode was set to Track?

CountryTom · 10-31-2017, 01:26 PM

Quote:

Originally Posted by travislambert

I assume the exhaust valve mode was set to Track?

It was actually Track first time and tour second. Wondering if the fog impacted this since it was a low ceiling.

*Mr. Wyndham* · 10-31-2017, 01:43 PM

Manual warns against performance driving with valves always closed (aka Stealth Mode). I assume there's a little too much back-pressure built up. Dunno if that helps, but I wanted to share.

If you don't care about that...pushing "Stealth" in the settings menu for exhaust sound should do the trick.

soceur77 · 10-31-2017, 04:14 PM

it just bugs me there is a sound check at a race track....its not like youre driving a 1800hp dragster....lol

Can'tHave2MuchHP · 10-31-2017, 04:33 PM

There's no way you can make any car but especially a supercharged engine like the LT4 quieter than it is stock without compromises. And in this case it could be power/reliability/exhaust temps/burn your cats. Or you're going to have it tuned after these new Cats ("Laguna pipes") are installed and going to be forced to run different timing and probably more fuel to keep the cats cool. That's my guess at least because I've never seen this done and don't know how in the heck it's safe or worth it. (And it probably won't make a difference if both Track and Stealth got you flagged.)

bensf · 10-31-2017, 08:15 PM

Quote:

Originally Posted by CountryTom

Hey all,

First off, sorry if this is out there but I tried search first.

Has anyone fabricated a clip that holds the muffler closed? Or better yet - a GPS-based valve device like this for Porsche? (https://rennlist.com/forums/991-gt3-...nd-checks.html)

Had Laguna Seca yesterday and blew sound 2x while severely lifting past the sound booth. (97 dB both times. But very low fog) Laguna pipes will help on a clear day but not in fog. Just researching for now and may settle on the Laguna Pipes in the end. Appreciate the insights

Thx!

Ran one of the first gps units from that Rennlist post. After 2.5 years, we have never been black flagged once and no issue with the car as well. Hopefully a similar solution can be made for our cars. Where did you get the Laguna pipes?

MoreSpeed · 10-31-2017, 09:14 PM

There is old trick of fabricating a 90-degree downpipe forcing the exhaust down to the ground. I have done sound before at events. It is not at all how loud your car is at your car. The measurements are taken at a distance. It is more how sound travels from your car. Probably pretty cheap to temporarily take off the decorative end tips and bolt something on.

Can'tHave2MuchHP · 10-31-2017, 10:12 PM

Quote:

Originally Posted by MoreSpeed

There is old trick of fabricating a 90-degree downpipe forcing the exhaust down to the ground. I have done sound before at events. It is not at all how loud your car is at your car. The measurements are taken at a distance. It is more how sound travels from your car. Probably pretty cheap to temporarily take off the decorative end tips and bolt something on.

The tips are welded on.

MoreSpeed · 11-01-2017, 05:32 PM

Quote:

Originally Posted by Can'tHave2MuchHP

The tips are welded on.

I get that. Easy to cut off and then jury rig something. Certainly easier than somehow fabricating clips that hold the muffler closed.

Can'tHave2MuchHP · 11-01-2017, 08:23 PM

Maybe it's because I've never gotten flagged at a track nor seen anyone at the track I've been to, but, what's the big deal with blowing the sound at a track like Laguna? Do they ban you? Throw you out? Or can you keep blowing it?

Unless you must track there and continuing to track there will result in being thrown out or banned, then I say don't mess with your car. If you have to track there, sounds like you're altering your cars exhaust for the worse.

Gunkk · 11-02-2017, 03:25 AM

you had to ask...

BMWM.D. · 11-02-2017, 09:50 AM

Quote:

Originally Posted by Gunkk

you had to ask...

Yeah...kinda. It's mainly the rich people who built houses near Laguna Seca. I know, right? Build a house near a historic race track, then get mad about noise.

I just got a note from my neighbor last weekend saying my ZL1 is "excessively and unnecessarily loud". I thought that was pretty funny, as the car is bone stock. I told him there wasn't much I could do, other than what I already do (not taking it out early in the AM or late at night, going easy on the throttle leaving, etc.). Part of me wants to go out into the street behind his house and do a big smoky line-lock burnout, but I've restrained myself so far. Haha...

*Mr. Wyndham* · 11-02-2017, 10:03 AM

Quote:

Originally Posted by BMWM.D.

Yeah...kinda. It's mainly the rich people who built houses near Laguna Seca. I know, right? Build a house near a historic race track, then get mad about noise.

I just got a note from my neighbor last weekend saying my ZL1 is "excessively and unnecessarily loud". I thought that was pretty funny, as the car is bone stock. I told him there wasn't much I could do, other than what I already do (not taking it out early in the AM or late at night, going easy on the throttle leaving, etc.). Part of me wants to go out into the street behind his house and do a big smoky line-lock burnout, but I've restrained myself so far. Haha...

I'd return his note with another saying: "thank you!"

10-30-2017, 11:33 PM	#1
CountryTom Drives: 2017 ZL1 - Nightfall Gray Metallic Join Date: May 2017 Location: Fremont, CA Posts: 30	Silencing the Beast Hey all, First off, sorry if this is out there but I tried search first. Has anyone fabricated a clip that holds the muffler closed? Or better yet - a GPS-based valve device like this for Porsche? (https://rennlist.com/forums/991-gt3-...nd-checks.html) Had Laguna Seca yesterday and blew sound 2x while severely lifting past the sound booth. (97 dB both times. But very low fog) Laguna pipes will help on a clear day but not in fog. Just researching for now and may settle on the Laguna Pipes in the end. Appreciate the insights Thx!

10-31-2017, 01:43 PM	#4
Mr. Wyndham I used to be Dragoneye... Drives: 2018 ZL1 1LE Join Date: Jan 2007 Location: Buffalo, NY Posts: 31,873 View My Garage	Manual warns against performance driving with valves always closed (aka Stealth Mode). I assume there's a little too much back-pressure built up. Dunno if that helps, but I wanted to share. If you don't care about that...pushing "Stealth" in the settings menu for exhaust sound should do the trick. __________________ *"Keep the faith."* - Fbodfather

10-31-2017, 09:14 PM	#8
MoreSpeed Drives: 2017 Hyper Blue A10 ZL1 Join Date: Dec 2016 Location: New England Posts: 716	There is old trick of fabricating a 90-degree downpipe forcing the exhaust down to the ground. I have done sound before at events. It is not at all how loud your car is at your car. The measurements are taken at a distance. It is more how sound travels from your car. Probably pretty cheap to temporarily take off the decorative end tips and bolt something on. __________________ - Life is a highway... I want to ride it all night long... Sold 2010 997 GT3, 2016 WRX, 2006 997 C2S, 2003 996 C4S, 2001 Boxster S, 1997 E420 AMG etc..

11-02-2017, 03:25 AM	#12
Gunkk Thank you Al Oppenheiser! Drives: Red Hot A10 ZL1 Convertible Join Date: Jun 2017 Location: Sarasota, FL Posts: 5,183 View My Garage	you had to ask... Attached Images

10-31-2017, 09:14 AM	#2
travislambert Drives: '17 ZL1 Join Date: Jul 2016 Location: Fairmont, WV Posts: 1,567	I assume the exhaust valve mode was set to Track?

10-31-2017, 04:14 PM	#5
soceur77 Drives: 17 NFG ZL1 17 GTR 22 RS6 Join Date: Apr 2017 Location: Upper Marlboro MD Posts: 625	it just bugs me there is a sound check at a race track....its not like youre driving a 1800hp dragster....lol

10-31-2017, 04:33 PM	#6
Can'tHave2MuchHP Drives: Fast Join Date: Mar 2015 Location: Michigan Posts: 3,696	There's no way you can make any car but especially a supercharged engine like the LT4 quieter than it is stock without compromises. And in this case it could be power/reliability/exhaust temps/burn your cats. Or you're going to have it tuned after these new Cats ("Laguna pipes") are installed and going to be forced to run different timing and probably more fuel to keep the cats cool. That's my guess at least because I've never seen this done and don't know how in the heck it's safe or worth it. (And it probably won't make a difference if both Track and Stealth got you flagged.)

11-01-2017, 08:23 PM	#11
Can'tHave2MuchHP Drives: Fast Join Date: Mar 2015 Location: Michigan Posts: 3,696	Maybe it's because I've never gotten flagged at a track nor seen anyone at the track I've been to, but, what's the big deal with blowing the sound at a track like Laguna? Do they ban you? Throw you out? Or can you keep blowing it? Unless you must track there and continuing to track there will result in being thrown out or banned, then I say don't mess with your car. If you have to track there, sounds like you're altering your cars exhaust for the worse.

User Name		Remember Me?
Password