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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
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