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Trying to quiet down Bridgeport FD

Old 03-09-18, 05:29 PM
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Trying to quiet down Bridgeport FD

Hey guys,

I am looking to quiet down my Bridgeport FD RX7.. I am getting HoA complaints and have no choice but to atleast try to quiet it down a bit.

I was looking at either a Vibrant Ultra-quiet resonator, Vibrant Streetpower Muffler or a Magnaflow 4-6" Round muffler.

The cold start / idle is all that really matters as I can creep out of my neighborhood pretty fast and then be as loud as I want.

Not sure if a resonator would do the trick for the idle as I heard it only really helps when you're on the gas.

Any help would be appreciated!
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Old 03-09-18, 07:26 PM
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I used an offset in/out through type SPT Subaru muffler at the back and it kept things very reasonable
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Old 03-09-18, 07:29 PM
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Originally Posted by dpartinvr4 View Post
I used an offset in/out through type SPT Subaru muffler at the back and it kept things very reasonable
Happen to have a video?

Thank you for the input!
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Old 03-09-18, 07:46 PM
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My experience is straight through mufflers will knock the high frequency out and can make the exhaust pleasant enough to the ears if there are enough/long enough.

The issue is the low frequency that gets through rattles people dishes in the cupboards and their windows and its not easy to take this out with large diameter straight through mufflers.

If you also find this to be the case for you; you can attenuate the low frequency by putting in a "throttle plate" style variable exhaust valve so the low frequency hits the plate when closed driving around your neighborhood and bounces back toward the motor while the exhaust flow gets pushed out little holes in the throttle plate. Then when you want flow you can open the valve.

You can do the same with the exhaust tip silencers, but its a pain to stop and take it out and put the hot piece of metal in a box and into your car every time you leave your neighborhood.

Don't tune or drive your rotary hard with either one, it is really hard on the engine and you can see the difference in VE in the AFRs with the valve open/closed or tip silencer in/out.
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Old 03-10-18, 11:09 AM
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i have a P port in a 1st gen, and i tried a bunch of stuff clamped to the tail pipe, and the most effective thing was a resonated tip that is 2 pipes instead of one big one.

the DB goes down a bit, but it knocks the low frequencies way down.

the lower the frequency the longer the wave is, or the larger the pipe diameter the lower frequency it will be tuned too. look at a pipe organ.
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Old 03-10-18, 08:29 PM
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the header merges at the diff and about 3" of pipe into the 2.5" muffler
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