SCCA Exhaust db Limit

14BlackCherry · 04-07-2016, 02:39 AM

I know this subject has been covered, but just wanted to get some input from others as I'm concerned a little. So I have berk HFC, and a Tomei full cat back, y-pipe etc... I'm running STR this year.

The car is ridiculously loud under full throttle. So much so I went and purchased this sound meter from guitar center:

American Recorder Technologies Sound Level Meter | Guitar Center

At 50 feet and about 5-6 feet in the air as my friend was holding it, the car under full throttle was anywhere from 97-97.5db. The Tomei silencer lessened the db reading less than 2db. According to the SCCA rules if you exceed 100db you'll need to fix the issue prior to your next run. If you exceed 97db sound must notify the sound control steward. My question has anyone here exceeded sound before or come close and if so what options are available to remedy the issue? Turn down?

Thanks for you time.

Here's the rule:

The maximum level will be 100 dBA. The measurement will be taken at a point where the vehicle can reasonably be expected to be under load at full throttle. The measuring point will be 50 feet from the edge of the course using an ANSI Type 2 sound meter set to “A” weighting, “Slow” response. The microphone will be 3 to 4 feet above ground level, positioned perpendicular to vehicle direction of travel. The microphone will be away from structures (e.g., buildings) as is practical. If a driver in a vehicle exceeds 97 dBA, the Chief Steward or his/her designated representative will be notified by the Sound Control Steward or representative. The Chief Steward or representative will notify the driver of any measurement over 97 dBA.

BGTV8 · 04-07-2016, 03:26 AM

Our race vehicles are subject to a 95Dba 30 foot drive by test with car under full laod.

My current race car (not Z34) is a 5-litre V8 with 14.5:1 compression pistons on E85 and carbon airbox that breathes thru a AMG C63 filter ..... so induction noise (which is a significant contributor to noise on the car) is about as "muffled" as it can be

I use SpinTech race mufflers - 1 either side and consistently run 94.3 Dba, so I suggest you might like to investigate these mufflers for your car.

www.spintechmufflers.com

My current race car engine uses a pair of 1441's and I have a pair of 3331XL for my new Z34 engine (will be 9000rpm capable, hi-comp on E85).

Zauskycop · 04-07-2016, 06:52 AM

It's an easy fix if you can do it..put some extensions on your exhaust that point them away from the meter. Removable of course.

Tracy Ramsey

gomer_110 · 04-07-2016, 07:05 AM

Quote:

Originally Posted by Zauskycop

It's an easy fix if you can do it..put some extensions on your exhaust that point them away from the meter. Removable of course.

Tracy Ramsey

Pointing them at the ground is the most common.

14BlackCherry · 04-08-2016, 06:58 AM

I've heard of the turn down tips that people point to the ground. I recall seeing a SSM RX-7 at Spring Nats running one. Our first local event is May 1st we'll see if anyone says anything.

I appreciate the input.

Slartibartfas · 04-15-2016, 03:02 PM

Be different, point them up. You'll be even quieter as there'll be no reflections off the pavement.

FPenvy · 04-15-2016, 03:08 PM

I'm not allowed to play at auto x events due to this rule.

I then proceeded to tell the old guys running it to blow me.

oh well. they wouldn't let me swerve around cones in an empty lot against miatas that were falling apart......

Slartibartfas · 04-15-2016, 03:21 PM

Houston's BMW & Porsche clubs band together to run an autoX every month. They don't run under SCCA rules. Does your area have something similar?

FPenvy · 04-15-2016, 03:24 PM

Quote:

Originally Posted by Slartibartfas

Houston's BMW & Porsche clubs band together to run an autoX every month. They don't run under SCCA rules. Does your area have something similar?

there's SCCA and the club one which is the one that told me not to come back.

I may go do the SCCA one considering I know people with similar volume exhausts that run there.

imjello · 04-18-2016, 11:01 PM

Quote:

Originally Posted by BGTV8

... I have a pair of 3331XL for my new Z34 engine (will be 9000rpm capable, hi-comp on E85).

Please point me to your build thread

BGTV8 · 04-19-2016, 12:07 AM

Here

BGTV8 VQ40HRGA Race engine build

imjello · 04-19-2016, 09:49 AM

Quote:

Originally Posted by BGTV8

Here

BGTV8 VQ40HRGA Race engine build

ITB!!!!! rep!

04-07-2016, 02:39 AM	#1 (permalink)
14BlackCherry Base Member Join Date: Jun 2014 Location: Colorado Age: 37 Posts: 178 Drives: 14 Nissan 370z BC M6 Rep Power: 11	SCCA Exhaust db Limit I know this subject has been covered, but just wanted to get some input from others as I'm concerned a little. So I have berk HFC, and a Tomei full cat back, y-pipe etc... I'm running STR this year. The car is ridiculously loud under full throttle. So much so I went and purchased this sound meter from guitar center: American Recorder Technologies Sound Level Meter \| Guitar Center At 50 feet and about 5-6 feet in the air as my friend was holding it, the car under full throttle was anywhere from 97-97.5db. The Tomei silencer lessened the db reading less than 2db. According to the SCCA rules if you exceed 100db you'll need to fix the issue prior to your next run. If you exceed 97db sound must notify the sound control steward. My question has anyone here exceeded sound before or come close and if so what options are available to remedy the issue? Turn down? Thanks for you time. Here's the rule: The maximum level will be 100 dBA. The measurement will be taken at a point where the vehicle can reasonably be expected to be under load at full throttle. The measuring point will be 50 feet from the edge of the course using an ANSI Type 2 sound meter set to “A” weighting, “Slow” response. The microphone will be 3 to 4 feet above ground level, positioned perpendicular to vehicle direction of travel. The microphone will be away from structures (e.g., buildings) as is practical. If a driver in a vehicle exceeds 97 dBA, the Chief Steward or his/her designated representative will be notified by the Sound Control Steward or representative. The Chief Steward or representative will notify the driver of any measurement over 97 dBA.

04-15-2016, 03:02 PM	#6 (permalink)
Slartibartfas Track Member Join Date: Apr 2016 Location: Houston Posts: 551 Drives: 2011 G37S sedan Rep Power: 10	Be different, point them up. You'll be even quieter as there'll be no reflections off the pavement. __________________ 2011 Journey Sport sedan 7AT \| SPL front, SPC rear camber arms \| ARK Grip cat-back \|

04-15-2016, 03:21 PM	#8 (permalink)
Slartibartfas Track Member Join Date: Apr 2016 Location: Houston Posts: 551 Drives: 2011 G37S sedan Rep Power: 10	Houston's BMW & Porsche clubs band together to run an autoX every month. They don't run under SCCA rules. Does your area have something similar? Brendan likes this. __________________ 2011 Journey Sport sedan 7AT \| SPL front, SPC rear camber arms \| ARK Grip cat-back \|

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04-07-2016, 03:26 AM	#2 (permalink)
BGTV8 A True Z Fanatic Join Date: Dec 2009 Location: 03350 Australia Posts: 1,514 Drives: 09 Nissan 370Z M6 Rep Power: 39974	Our race vehicles are subject to a 95Dba 30 foot drive by test with car under full laod. My current race car (not Z34) is a 5-litre V8 with 14.5:1 compression pistons on E85 and carbon airbox that breathes thru a AMG C63 filter ..... so induction noise (which is a significant contributor to noise on the car) is about as "muffled" as it can be I use SpinTech race mufflers - 1 either side and consistently run 94.3 Dba, so I suggest you might like to investigate these mufflers for your car. www.spintechmufflers.com My current race car engine uses a pair of 1441's and I have a pair of 3331XL for my new Z34 engine (will be 9000rpm capable, hi-comp on E85).

04-07-2016, 06:52 AM	#3 (permalink)
Zauskycop Base Member Join Date: May 2011 Location: Hinckley IL Posts: 228 Drives: 2012 370Z, '16 Miata Rep Power: 14	It's an easy fix if you can do it..put some extensions on your exhaust that point them away from the meter. Removable of course. Tracy Ramsey

04-08-2016, 06:58 AM	#5 (permalink)
14BlackCherry Base Member Join Date: Jun 2014 Location: Colorado Age: 37 Posts: 178 Drives: 14 Nissan 370z BC M6 Rep Power: 11	I've heard of the turn down tips that people point to the ground. I recall seeing a SSM RX-7 at Spring Nats running one. Our first local event is May 1st we'll see if anyone says anything. I appreciate the input.

04-19-2016, 12:07 AM	#11 (permalink)
BGTV8 A True Z Fanatic Join Date: Dec 2009 Location: 03350 Australia Posts: 1,514 Drives: 09 Nissan 370Z M6 Rep Power: 39974	Here BGTV8 VQ40HRGA Race engine build