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Hawaii Exhaust & Muffler Laws (2026)

Info: For cars, the muffler can't be noticeably louder than the factory one; motorcycles and mopeds need a muffler, and a cutout or bypass (which routes exhaust around the muffler) isn't allowed.

InfoVerified Jun 19, 2026

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For cars, the muffler can't be noticeably louder than the factory one; motorcycles and mopeds need a muffler, and a cutout or bypass (which routes exhaust around the muffler) isn't allowed. Hawaii sets no fixed decibel limit (HRS §§ 291-24.5, 291-24).

Official source: capitol.hawaii.gov →

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