Turbos and Mufflers (and Bears, oh my!)

[Tosh]

I'm currently driving a turbo diesel from 2007 (early common-rail, no SCR system, but does have a DPF).

This vehicle did not come with a conventional muffler - it had a dinky little "resonator" at the rear. I learned that a muffler is not required on turbo diesel exhaust, because the turbocharger itself is the noise-mitigation device. The replacement exhaust I put on it didn't even have a place to connect a muffler.

All legal. If you have a Turbo, with no Muffler, don't worry about Bears.

Question: does the same thing apply to gasoline turbocharged engines? Is it legal to delete your muffler (as long as you don't live in California)?

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[Tosh]

I've been researching this question, and there are many variables. No simple answer, apparently.

Yes, it's true that a muffler is NOT needed for noise mitigation when a turbocharger is employed

"With the turbochargers installed at the very rear of the vehicle, no additional mufflers were needed. The turbos’ restriction serves to reduce the exhaust note."
- https://www.musclecardiy.com/perfor...r-supercharged-and-turbocharged-applications/

However, state laws have different definitions regarding "noise mitigation". Some states just outright forbid exhaust modifications, others actually measure the noise output in decibels.
- https://www.semasan.com/resources/exhaust-noise-laws-state

I find it interesting that my Jeep, which never had a muffler, was sold legally in the state of Texas, where the law states:

"§ 547.604. Muffler Required


(a) A motor vehicle shall be equipped with a muffler in good working condition that continually operates to prevent excessive or unusual noise.


(b) A person may not use a muffler cutout, bypass, or similar device on a motor vehicle."

Even after I had installed my MBRP exhaust, which visibly did not have a muffler, I passed state inspection 4 times!

I think I'm going to remove my muffler when I get my Ford truck, and see what happens.

 

[Gen14]

Its going to be loud but it is legal.

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