100DB Track Limit

andy_meng1024 · 12-18-2018, 01:39 PM

A new local track requires the noise level to be under 100DB directly behind the car at and 95DB on some corners but with a bit distance. I currently have FI LTH and CBE with 18" resonator but it's still too loud, any idea on how to quiet it down without sacrificing power? I also have the side pipe welded to the muffler to reduce the drone at about 3k rpm, but that doesn't really do much at high rev. Thanks in advance.

gomer_110 · 12-18-2018, 08:04 PM

How the hell are you over 100dB with that setup? I have that same setup and consistently come in around 93-94 dB. Maybe try adding some turndowns on the tips that are pointed down to help quiet it down a bit.

yaoxiao4 · 12-18-2018, 09:47 PM

thats crazy, granted i dont have the FI LTH but my FI CBE (also 18 res) doesnt even break 90db on Laguna Seca

andy_meng1024 · 12-18-2018, 09:49 PM

Quote:

Originally Posted by gomer_110

How the hell are you over 100dB with that setup? I have that same setup and consistently come in around 93-94 dB. Maybe try adding some turndowns on the tips that are pointed down to help quiet it down a bit.

What RPM did they use for sound level? The local track asks me to rev to 6k.

iPhoneTapatalk

gomer_110 · 12-18-2018, 10:00 PM

I do autox with SCCA. Generally they setup the sound meter along the course at a point where most people will be near redline. I'm sure I've been measured everywhere from 5500 to 7600 rpm.

Do you know what the settings on the sound meter are. Most have a peak capture mode along with an averaging mode. Averaging mode is what most organization use because peak basically screws everyone. I've see bone stock 911 GT3's hit 100 when measured in peak mode.

Easiest first attempt to get quieter would be to get some 90° ductwork elbows that will slip over the exhaust tips and use hose clamps to secure them in place. Make sure they are pointed down at the ground. This should help noticeable. It won't look pretty but won't lose performance and they can be removed after the event.

Elmo370z · 12-20-2018, 10:01 PM

Thank god I live in Florida. Car to loud for the track is ridiculous

Rusty · 12-22-2018, 03:19 PM

Quote:

Originally Posted by Elmo370z

Thank god I live in Florida. Car to loud for the track is ridiculous

A lot of tracks are like that now.

gomer_110 · 12-22-2018, 05:00 PM

Quote:

Originally Posted by Elmo370z

Thank god I live in Florida. Car to loud for the track is ridiculous

I would normally agree with you but the fact is there's always those one or two aholes that show up with a straight piped POS that is loud for the sake of being loud. These jacka$$es are the ones that have ruined it for the rest of us.

Rusty · 12-22-2018, 05:11 PM

Quote:

Originally Posted by gomer_110

I would normally agree with you but the fact is there's always those one or two aholes that show up with a straight piped POS that is loud for the sake of being loud. These jacka$$es are the ones that have ruined it for the rest of us.

You ever get passed by a NACRAPER during a track day? Fvcker's will make your ears bleed.

gomer_110 · 12-22-2018, 05:46 PM

For me it's the miatas and civics that show up at autox with straight pipes that argue putting a muffler on would kill their power.

Spooler · 12-22-2018, 10:21 PM

Quote:

Originally Posted by gomer_110

For me it's the miatas and civics that show up at autox with straight pipes that argue putting a muffler on would kill their power.

What power? LOL

gomer_110 · 12-22-2018, 10:40 PM

Precisely their argument. When they only make ~100 hp, giving up 5 hp for a muffler is a 5% drop in in power.

12-18-2018, 01:39 PM	#1 (permalink)
andy_meng1024 Premium Member Join Date: Nov 2009 Location: Taipei Posts: 233 Drives: 2012 370z Rep Power: 3381	100DB Track Limit A new local track requires the noise level to be under 100DB directly behind the car at and 95DB on some corners but with a bit distance. I currently have FI LTH and CBE with 18" resonator but it's still too loud, any idea on how to quiet it down without sacrificing power? I also have the side pipe welded to the muffler to reduce the drone at about 3k rpm, but that doesn't really do much at high rev. Thanks in advance. __________________ Current: 2015 C200 / 2018 Cayenne / 2012 370z / 2012 C250 Coupe Gone: 2013 Cayenne / 2004 Cayenne S / 2003 SL55 AMG / 2008 C300 / 2006 350z / 2006 C280 4Matic

12-18-2018, 08:04 PM	#2 (permalink)
gomer_110 A True Z Fanatic Join Date: Aug 2011 Location: Perrysburg, OH Posts: 17,992 Drives: '11 Nismo #528 GM Rep Power: 36941	How the hell are you over 100dB with that setup? I have that same setup and consistently come in around 93-94 dB. Maybe try adding some turndowns on the tips that are pointed down to help quiet it down a bit. Chuck33079, Rusty and Hotrodz like this. __________________ '11 370Z Nismo #528 Fast Intentions \| Stillen \| Motordyne \| Uprev \| CSF \| Zspeed \| Z1 Motorsports \| AST \| Swift \| SPC \| SPL \| Whiteline \| Hotchkis \| Bride \| Schroth \| Robispec \| Cusco \| Nismo \| Volk \| Forgestar \| Hoosier \| RJM '17 Titan Bone Stock

12-18-2018, 10:00 PM	#5 (permalink)
gomer_110 A True Z Fanatic Join Date: Aug 2011 Location: Perrysburg, OH Posts: 17,992 Drives: '11 Nismo #528 GM Rep Power: 36941	I do autox with SCCA. Generally they setup the sound meter along the course at a point where most people will be near redline. I'm sure I've been measured everywhere from 5500 to 7600 rpm. Do you know what the settings on the sound meter are. Most have a peak capture mode along with an averaging mode. Averaging mode is what most organization use because peak basically screws everyone. I've see bone stock 911 GT3's hit 100 when measured in peak mode. Easiest first attempt to get quieter would be to get some 90° ductwork elbows that will slip over the exhaust tips and use hose clamps to secure them in place. Make sure they are pointed down at the ground. This should help noticeable. It won't look pretty but won't lose performance and they can be removed after the event. andy_meng1024 likes this. __________________ '11 370Z Nismo #528 Fast Intentions \| Stillen \| Motordyne \| Uprev \| CSF \| Zspeed \| Z1 Motorsports \| AST \| Swift \| SPC \| SPL \| Whiteline \| Hotchkis \| Bride \| Schroth \| Robispec \| Cusco \| Nismo \| Volk \| Forgestar \| Hoosier \| RJM '17 Titan Bone Stock

12-20-2018, 10:01 PM	#6 (permalink)
Elmo370z A True Z Fanatic Join Date: Apr 2013 Location: st. petersburg Posts: 5,709 Drives: 09 nissan 370z Sp M6 Rep Power: 295378	Thank god I live in Florida. Car to loud for the track is ridiculous madwi, Brendan, Spooler and 2 others like this.

12-22-2018, 05:46 PM	#10 (permalink)
gomer_110 A True Z Fanatic Join Date: Aug 2011 Location: Perrysburg, OH Posts: 17,992 Drives: '11 Nismo #528 GM Rep Power: 36941	For me it's the miatas and civics that show up at autox with straight pipes that argue putting a muffler on would kill their power. Rusty, Hotrodz and Spooler like this. __________________ '11 370Z Nismo #528 Fast Intentions \| Stillen \| Motordyne \| Uprev \| CSF \| Zspeed \| Z1 Motorsports \| AST \| Swift \| SPC \| SPL \| Whiteline \| Hotchkis \| Bride \| Schroth \| Robispec \| Cusco \| Nismo \| Volk \| Forgestar \| Hoosier \| RJM '17 Titan Bone Stock

12-18-2018, 09:47 PM	#3 (permalink)
yaoxiao4 Enthusiast Member Join Date: Feb 2017 Location: Bay Area Posts: 320 Drives: 13 370z Black M6 Rep Power: 8	thats crazy, granted i dont have the FI LTH but my FI CBE (also 18 res) doesnt even break 90db on Laguna Seca

12-22-2018, 10:40 PM	#12 (permalink)
gomer_110 A True Z Fanatic Join Date: Aug 2011 Location: Perrysburg, OH Posts: 17,992 Drives: '11 Nismo #528 GM Rep Power: 36941	Precisely their argument. When they only make ~100 hp, giving up 5 hp for a muffler is a 5% drop in in power. Hotrodz likes this. __________________ '11 370Z Nismo #528 Fast Intentions \| Stillen \| Motordyne \| Uprev \| CSF \| Zspeed \| Z1 Motorsports \| AST \| Swift \| SPC \| SPL \| Whiteline \| Hotchkis \| Bride \| Schroth \| Robispec \| Cusco \| Nismo \| Volk \| Forgestar \| Hoosier \| RJM '17 Titan Bone Stock

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