Aftermarket Exhaust in Michigan
Replacing the exhaust system is legal in Michigan, but a muffler in good working order is required and cutouts or bypasses are prohibited. There is no statutory 'no louder than stock' rule — the standard is that the exhaust must not produce excessive or unusual noise.
Verified against primary sources · August 2026
What the law says
Replacing the exhaust system is legal in Michigan, but a muffler in good working order is required and cutouts or bypasses are prohibited. There is no statutory 'no louder than stock' rule — the standard is that the exhaust must not produce excessive or unusual noise. Removing the catalytic converter is prohibited by federal law (Clean Air Act § 203) regardless of state rules. Baffle removal and excessive fumes are banned, and the tailpipe and resonator must be retained if the vehicle was originally designed with them. Michigan has no state inspection.
Specific Limits
- Cutouts
- prohibited
- Muffler required
- Yes
- Louder than stock
- not addressed; excessive noise standard applies
- Catalytic converter
- removal prohibited by federal law
Exceptions & Exemptions
Exhaust system must include a muffler and may not exceed noise levels that would be unreasonable under normal operating conditions. Catalytic converters required on vehicles originally equipped with them. Cutouts, bypasses, or similar devices that allow exhaust to exit before the muffler are prohibited.
Frequently Asked Questions
Are aftermarket exhaust legal in Michigan?
What are the exact aftermarket exhaust limits in Michigan?
Are there exceptions for aftermarket exhaust in Michigan?
Street-legal aftermarket exhaust picks
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