In NH, we pride ourselves on being a free state, but that doesn’t mean that we don’t have rules. When it comes to mufflers and exhaust, NH has very specific rules, in fact. At Lou’s Custom Exhaust, we are committed to providing you with the best custom exhaust systems and exhaust repairs that will keep your car running and ensure that you pass inspection. Here is a quick overview of the NH exhaust laws.
Keep the noise down
NH law requires that all motor vehicles be equipped with a working muffler. Additionally, some states specify that the muffler must reduce noise so that it does not exceed a certain decibel level (usually 80 or 95 decibels). NH does not set a specific decibel level; the law only states that a vehicle’s muffler must “prevent excessive or unusual noise.” While the state leaves the definition of “excessive or unusual noise” open to interpretation, certain counties and cities may have more specific regulations. It’s best to check the noise regulations where you live. If you are planning to get custom exhaust work done on your car knowing these regulations will help. The state of NH also prohibits muffler cutouts and bypasses.
Don’t pollute (too much)
Although gasoline-powered vehicles will never be zero-emissions vehicles, car manufacturers are doing what they can to reduce emissions. Your car’s catalytic converter is what controls the oxygen level to keep your car’s air to fuel ratio as close to the ideal point as possible. NH is one of the 34 US states that require emissions testing to pass inspection; NH’s specific law is that all vehicles 20 years old and newer must undergo an emissions test as part of the inspection. NH law again only states that fumes, smoke, and residue must not be “excessive.”
No straight pipes
Combining the elements of the first two parts of NH’s law affecting car mufflers, straight pipe exhaust systems are prohibited in NH. Straight pipe exhaust systems have no dampeners between the exhaust headers and the rear of the vehicle. This means the exhaust system has no muffler or catalytic converter. To comply with both NH’s noise regulations and emissions standards, a car with a straight pipe exhaust system will not pass inspection. Installing such a system in your car could incur a hefty fine, too.
NH Exhaust Professionals at Lou’s Custom Exhaust
Our NH exhaust professionals at Lou’s Custom Exhaust are well-versed in the NH exhaust laws and are ready to build or repair the perfect custom exhaust system for your car. Contact Lou’s Custom Exhaust today at 603-249-5918 to schedule an appointment to take care of all your NH exhaust needs.
