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In a message dated 12/21/2003 9:13:48 PM Central Standard Time,
sqpilot@earthlink.net writes:
<< Rusty....I'm glad I found someone familiar with the Borla muffler. If I
understand you correctly, using only a Borla muffler on my aircraft, it might be
too loud? Thanks. Paul Conner >>
I have a 4" Borla on my race car. It gives us 97DB at 50 feet and wide open
throttle under load. It is all stainless. It has been on the car for 4 years. I
would like to point out that 97 DB is a mind shattering amount of sound
energy. We are limited to 103 DB. The V8 powered TransAm cars didn't require
mufflers at 105 DB. Now they run giant Flowmasters. About the size of a small suit
case to make the 103 DB limit.
Years ago we started out with a big glasspacked Tube style. It lasted almost
a full weekend. First, spraying liquid glass, and then, melting the center
tube.
Then I made a stainless wool packed tube type out of a piece of a house jack
for the center tube and 4" carbon steel truck exhaust pipe for the outer tube.
It lasted a whole season. Getting pretty loud near the end. The stainless
wool turns to dust and blows away. Then the center tube melted. When I cut it
open to see why it had become so loud, about 6" of the center tube was missing
and all of the stainless wool was gone. Then we tried a Flowmaster 3 1/2" flat
suit case muffler. We went down to Sebring in central Florida. We had moved the
Flowmaster back from the engine about 4 feet to cut down the heat load, We
beat the Flowmaster to pieces.
Some pieces of baffling started to block the exit pipe. Every single weld
inside the case had failed. The muffler was swelled up like a giant pillow. I cut
the top off and welded all of the baffles back into place. I drilled 3/8"
holes behind each baffle and inserted 3/8" steel rods through one side and welded
the baffles to the rods. Then I put the top back on and welded both ends of
each rod to the case. We moved the whole mess to the rear of the car, and it
worked fine for the rest of that year. It is the most quiet of anything we ever
tried. I still have it. We put in the Borla because the Engine builder
specified a shorter system with 4" pipe diameter. The Borla starts about 3 feet from
the engine. It makes the DB limit, and it could be better if I turned the exit
tip down and to the rear.
Lynn E. Hanover
Car.jpg
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