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Author Topic: Springfield Dyno Exhaust @ Laguna Seca
tvance85
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Year : 2001
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We were planning to run the NASA HPDE event at LS and wondered if we would have any issues with this exhaust (92 db at 50 feet is the requirement). I am assuming it will be over the limit...Id so what modifications can I make to make it legal for the weekend? Thanks in advance.

Sacslider
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No, you will not pass sound. At minimum you will need to add another muffler (most use a magna flow, offset in center out) to the system. You would be better off building a laguna system rather than cobbling something together if you will be there more than once this year.

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Craig Evans
#27 Spec Miata
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Ken Tubbs Verified Driver Made Donation to Website
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What can be done with a Mazda Comp exhaust specifically for Laguna?

Ken

Jack Arluck Verified Driver
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A Mazda Comp exhaust with a hollowed out cat will pass sound 99% of the time. A Mazda Comp exhaust with a full cat will pass sound all the time. That said I run a Mazda Comp with a hollowed cat and have never had a sound problem.

Jack

JD Morris Verified Driver Made Donation to Website
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A search turns up good answers to your question:

http://forum.specmiata.com/cgi-bin/ultimatebb.cgi?/topic/26/426.html#000019
http://forum.specmiata.com/cgi-bin/ultimatebb.cgi?/topic/44/928.html
http://forum.specmiata.com/cgi-bin/ultimatebb.cgi?/topic/26/51.html
http://forum.specmiata.com/cgi-bin/ultimatebb.cgi?/topic/26/257.html

JD

JeffG11 Verified Driver
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quote:
Originally posted by tvance306:
We were planning to run the NASA HPDE event at LS and wondered if we would have any issues with this exhaust (92 db at 50 feet is the requirement). I am assuming it will be over the limit...Id so what modifications can I make to make it legal for the weekend? Thanks in advance.

I can't offer advice specific to Laguna Seca, but here is my experience with the Springfield Dyno Exhaust (SDE).

Waterford Hills has a requirement of 75 dB at the property line. I ran a SDE with a turn down pointed down and away from the sound wall. This system blew a 77 dB. People have had success with adding a 2.5" Supertrapp attached to the end of their SDE. The Supertrapp is good for approximately 3-4 dB, depending on weather. I recently tested a SDE, SDE w/Supertrapp, and a stock exhaust system on a chassis dyno. The Supertrapp only cost the car 1/2 hp.

For reference, my car blew a 94 dB with the SDE at Mid-Ohio during an OVR-SCCA regional this summer.

For what it is worth, I am going with the Supertrapp next year.

Jeff

[ 12-23-2007, 06:43 AM: Message edited by: JeffG11 ]

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Dave Lewis
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Can I have my Supertrapp back now Ski? [Big Grin]

tvance85
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Jeff - Thanks for the info, just what I was looking for.

Kim Ouye Verified Driver Made Donation to Website
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77db??? That doesn't sound right...I put on a Laguna specific exhaust system and it blows sound at 90db once in a while. The SD exhaust I have is orders of magnitude louder...more like 96db-98db...

I found a 90 deg elbow to be worth maybe 1 db at LS...

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Kim

91 BRG SMT RIP
06 MX-5 Cup

"Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting 'Holy sh*t...what a ride!'" - Unknown

NV Racer Verified Driver
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I asked for sound checks last time at Laguna with my SDE and 90 degree elbow during the ITA race. They recorded 97,98,97 if it's foggy or low overcast add a dB or two to those readings.

Dennis

   

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