FisterD's bypass mufflers - some feedback and some instrumented noise level readings.
11-06-2007, 02:12 PM
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Racer
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FisterD's bypass mufflers - some feedback and some instrumented noise level readings.
Hi guys,
I finally got around to sending a set of Bischoffs to Darin (FisterD). He welded in 2" bypasses, and did a really nice job at a reasonable price - check out the pictures of the welds.
There is no drone, and they are perfect for my commute. They have a stock sound quality at cruise, but bark when you rev up the engine. They sound FANTASTIC - I'm very happy with them.
I've never seen any quantitative measurements of the change in sound levels for this modification, so I used my consumer-grade digital meter to take some samples. Generally, the bypasses are 1-2dB louder.
Here's the sound level data - it's A-weighted dB with 10-second average samples. My car has RS motor mounts, which transmit more noise into the interior. Best to use these levels as comparisons between the two mufflers rather than absolute levels.
I was mostly concerned about noise while cruising, so I didn't take measurements while revving the car up - it should be loud then, right?
Generally you don't want to be exposed to anything over 85 dBA for more than a couple hours per day. Anything over around 80 dBA is generally considered annoying over long periods. Check out the Fed's OSHA site for guidelines.
I finally got around to sending a set of Bischoffs to Darin (FisterD). He welded in 2" bypasses, and did a really nice job at a reasonable price - check out the pictures of the welds.
There is no drone, and they are perfect for my commute. They have a stock sound quality at cruise, but bark when you rev up the engine. They sound FANTASTIC - I'm very happy with them.
I've never seen any quantitative measurements of the change in sound levels for this modification, so I used my consumer-grade digital meter to take some samples. Generally, the bypasses are 1-2dB louder.
Here's the sound level data - it's A-weighted dB with 10-second average samples. My car has RS motor mounts, which transmit more noise into the interior. Best to use these levels as comparisons between the two mufflers rather than absolute levels.
I was mostly concerned about noise while cruising, so I didn't take measurements while revving the car up - it should be loud then, right?
Generally you don't want to be exposed to anything over 85 dBA for more than a couple hours per day. Anything over around 80 dBA is generally considered annoying over long periods. Check out the Fed's OSHA site for guidelines.
Last edited by cowtown; 11-06-2007 at 02:28 PM.
