Exhaust noise reduction for HPDE

[rastta]

I have two ways of reducing sound on my Boxster. One is a set of supertrapps that bolt on the exhaust and the other is a set of "Laguna pipes" that I built which are essentially angled pipes with a small insert and exhaust packing stuffed in them. The pipes didn't work well enough to pass sound - 92dB was the limit and I was hitting 94-95 dB. The supertrapps were more effective but I still have to lift when going by the sound station. My car without either is at about 98dB wide open.

Pipes installed - 3" diameter


Inside


Inside #2


Supertrapps

[Topless]

I just always run stock exhaust when running under sound restrictions. Bolt it on and you have a sure thing, vs whack and hope, and maybe go home after 1 session.

[Geof3]

Originally Posted by rastta

I have two ways of reducing sound on my Boxster. One is a set of supertrapps that bolt on the exhaust and the other is a set of "Laguna pipes" that I built which are essentially angled pipes with a small insert and exhaust packing stuffed in them. The pipes didn't work well enough to pass sound - 92dB was the limit and I was hitting 94-95 dB. The supertrapps were more effective but I still have to lift when going by the sound station. My car without either is at about 98dB wide open.

Pipes installed - 3" diameter


Inside


Inside #2


Supertrapps

That looks sweet with the Supertrapps sticking out like that!

[AZ986S]

I know this is not for the purists
Here's my fist low budget / in a hurry attempt at turn down tips.
I used 45 degree 1 1/2 in ID galvanized exhaust piping elbows, wedged inside the ID of the round pipe in the Borla muffler. Then I used exhaust patching sheet aluminum (malleable) and fabricated 5in wide by 12 in long pieces that wrap around the oval Borla tip and then around the 1 1/2 in elbow pipe. Then I used hose clamps to attach to both. As you tighten the pipe clamp, it draws in the sheet metal and does a good job at holding the pipe in place. It is not moving. I hope it works well enough for 96 dB. We shall see!