High-Performance Exhaust: Legalize It

High-Performance Exhaust: Legalize It

8/21/2003
By: Chris Neprasch

On a morning in early July, Chris Cruz was driving his blue 1992 Acura Integra through the streets of West Covina, California. His DA has a lowered stance, carbon fiber hood and rolls on 16-inch Work wheels. It is obviously a modified car and that morning it caught the attention of a local police officer. After pulling off to the side of the road, Cruz was issued a fix-it ticket for having a modified exhaust. “I write these tickets all the time,” the officer said. And with that, Chris was sent on his way.

Until recently, automotive enthusiasts like Cruz have been at the mercy of a police officer’s subjective judgment when being cited for violation California Vehicle Code 27151—modified exhaust. In a nutshell, the code says that in the state of California it is unlawful to modify a vehicle’s exhaust system in a matter that amplifies or increases the engine’s noise beyond 95 dB. Since police carry guns and not sound level meters, if an officer felt a car made too much noise a citation was issued.

The Specialty Equipment Market Association (SEMA) has been actively pushing for new legislation that would allow for more objective means of testing noise levels. They scored a big victory in 2001 when California Governor Gray Davis signed into legislation a bill that not only clearly states that it is legal to use a replacement exhaust system if it complies with the 95 dB limit, but also allowed courts to dismiss a citation if the exhaust is passes a test under SAE test procedure J1169. SEMA didn’t stop there. They continued to lobby and in 2002 Davis signed a new law that requires smog check stations that provide referee functions to perform exhaust noise-level testing.

Luckily, Cruz is an employee with Overboost and when we caught wind of his ticket, we wanted to put the new law to the test. We made a few phone calls to SEMA and the Bureau of Automotive Repair and were told that the centers would begin testing in late-July. Well, July came and went, but in early August we were contacted by Dan Burnett from the Bureau of Automotive Repair (BAR) and were able to arrange the first official exhaust sound pressure level test in Southern California. After confirming a date and time for the test we headed to a referee station at Rio Hondo Community College in Whittier, California.

Dealing with bureaucracy in the past, we were expecting the trip to be like going to get a root canal at an anesthetic-free dentist’s office. While Cruz was filling out paperwork in the office—which had a recent San Gabriel Valley Tribune article on illegal car modifications posted on the wall—we were outside talking to the student assistant about ways to do a B18 swap and get it legally certified. About 20 minutes and a safety inspection later we were ready for the test. (The inspection was for liability reasons, not road-legality reasons. –OVB)

Instead of having the exhaust tested by the highly precise ear of a beat officer, the referee station uses an electronic sound level meter to measure the noise emitted from the tailpipe. With our journalistic noses still sniffing around for flaws in the system our initial response was, “What if the meter is off?” Before we were even able to flap our big mouths we were shown how the meter is calibrated prior to each test to ensure accuracy.

The car was driven to a designated test area because under the procedure guidelines there cannot be buildings or anything else that might reflect sound waves within 10 feet of the car. The meter was placed eight inches above the ground and 20 inches away from the tailpipe at a 45-degree angle. The engine is then revved to three-quarters the maximum horsepower RPM, which in the case of the DA was 4,700 RPM, and that is where the sound level is measured.

The Integra passed with flying colors and only put out 90 dB. That might sound pretty close to the 95 dB limit at first glance, but for every 3 dB gain the sound doubles. Technically the car could have been nearly four times louder and still passed the test. A certificate and a decal on the ticket proved that the car’s exhaust was legal and they also noted the make and model of the system to help avoid future problems with the mounties. Since we no longer had to worry about being a roving band of outlaws anymore, we packed back in the DA and headed back to the office.

Not counting the time we spent talking cars with the staff, the process took less than an hour. Referee stations are now conducting the test all over California and are currently available by making an appointment through the BAR appointment center. The only catch is that you must first be issued a citation before you can take your car in, which somehow seems to conflict with the whole innocent until proven guilty thing. But it’s a big step in the right directions and much like Neo said at the end of Matrix, “I know that you’re afraid… afraid of us. You’re afraid of change. I don’t know the future. I didn’t come here to tell you how this is going to end. I came here to tell how it’s going to begin.”

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