[DeTomaso] ANSA mufflers

[Pantera Place]

Thanks Jim,

 

If loudness is related in any way to free flowing mufflers I expect I've
reached nirvana!!  I was using scale A but I need to do more testing.  The
high interior db is at idle and around the 2,000 RPM range.   It drops way
down at WOT and other RPMs.   My front engine inspection hatch is not
covered with any sound deading material so I expect I could cut the interior
db level with sound deading material work.  

 

Here is some OSHA sound level standards
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=standards
<http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=standards&p_i
d=9735> &p_id=9735 

 

Mike 

 

 

From: Pantdino [mailto:pantdino at aol.com] 
Sent: Monday, May 23, 2011 1:11 AM
To: PanteraPlace at hotmail.com; detomaso at realbig.com
Subject: Re: [DeTomaso] ANSA mufflers

 

Mike, is that with the meter on the A scale or the C scale?

The C scale includes much more low-frequency energy than the A, the latter
approximating the human ear.

 

I believe the 90dbA  (A meaning A scale) OSHA limit is assuming the employee
is wearing over the ear hearing protection. 

 

115db without protection would exceed the pain threshold for most people and
cause permanent hearing loss in a very short time indeed.

 

If you are really getting around 100db on the A scale you NEED to wear ear
plugs when you drive the car.

 

Jim

 

-----Original Message-----
From: Pantera Place <PanteraPlace at hotmail.com>
To: 'Pantdino' <pantdino at aol.com>; detomaso at realbig.com
Sent: Sun, May 22, 2011 1:31 pm
Subject: Re: [DeTomaso] ANSA mufflers

Jim,
 
 
 
Picked up a RS db meter today and did some testing.  At idle (performance
cam at about 850 RPM) the interior db is between 104 and 106 with the
windows down.  Windows up deduces the db to about 98.  At WOT (up to about
3,500) the interior db drops to about 98 and around 102 db cruising at 2,000
RPM.  Much less when out of the 2,000 RPM range.  
 
 
 
Five feet behind the car at idle is 101 db.   I'm somewhat surprised at the
high db readings, but because I've made the modifications one step at a time
the increase has been a slow process.  Expect I'm about a loud as I should
be without ear protection!       
 
 
 
OSHA work rules allow up to 90 db for 8 hours.  If the noise level reaches
115 dB hearing protection is required if the anticipated exposure exceeds 15
minutes.  
 
 
 
I'll do some testing with other Pantreras and see how the levels compare.  
 
 
 
Mike
 
 
 
 
 
From: Pantdino [mailto:pantdino at aol.com <mailto:pantdino at aol.com?> ] 
Sent: Saturday, May 21, 2011 8:39 PM
To: panteraplace at hotmail.com; detomaso at realbig.com
Subject: Re: [DeTomaso] ANSA mufflers
 
 
 
Mike,  
 
 
 
the resistance of airflow thru a tube is inversely proportional to the
fourth power of the radius-- so if you double the diameter of a hole the
resistance decreases to 1/16th. So yes, the resistance thru all those little
holes is much greater than thru a single  large hole.
 
 
 
What you describe regarding being disappointed with new mufflers being too
quiet is why I have not replaced the rusted-out, ratty-looking Ansas on my
car.  I like the sound and that is more important to me than appearance.
 
 
 
Do you have a sound level meter?  You can get one at Radio Shack very
inexpensively.  It would be interesting to see what levels you get behind
your car compared to a GTS, Hall, and other systems.
 
 
 
Jim Oddie
 
 
 
 
 
 
 
-----Original Message-----
From: Pantera Place <panteraplace at hotmail.com>
To: detomaso at realbig.com
Sent: Sat, May 21, 2011 2:57 pm
Subject: [DeTomaso] ANSA mufflers
 
I've been working on a series of modifications to my ANSA mufflers to
improve the exhaust flow and relieve back pressure.   The latest work is at
the bottom of this page http://www.panteraplace.com/page200.htm 
 
 
 
Mike 
 
 
 
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