Maximum legal exhaust noise?

[Software Guy]

I'm thinking about adding a couple of aftermarket components to my Civic Si, specifically a cat-back exhaust.

Can someone tell me what the legal limit is for exhaust noise here in CA? I think it's 93 dB, but I'm not sure. I would prefer to keep the noise well under the legal limit.

Thank you.

[PapaBear]

After market exhaust systems that are installed to amplify or increase the exhaust noise are illegal.

Modification of Exhaust Systems

27151. (a) No person shall modify the exhaust system of a motor vehicle in a manner which will amplify or increase the noise emitted by the motor of the vehicle so that the vehicle is not in compliance with the provisions of Section 27150 or exceeds the noise limits established for the type of vehicle in Article 2.5 (commencing with Section 27200). No person shall operate a motor vehicle with an exhaust system so modified.

(b) For the purposes of exhaust systems installed on motor vehicles with a manufacturer's gross vehicle weight rating of less than 6,000 pounds, other than motorcycles, a sound level of 95 dbA or less, when tested in accordance with Society of Automotive Engineers Standard J1169 May 1998, complies with this section. Motor vehicle exhaust systems or parts thereof include, but are not limited to, nonoriginal exhaust equipment.

Amended Sec. 10, Ch. 92, Stats. 2001. Effective January 1, 2002.

As far as noise limits are concerned, passenger vehicles manufactured after 1974 are limited to 80 dba.

Limits for Other Vehicles

27206. For the purposes of Section 27200, the following noise limits shall apply to any other motor vehicle, not specified in this article, manufactured:


(1) After 1967, and before 1973 .................................................. .........86 dba

(2) After 1972, and before 1975 .................................................. .........84 dba

(3) After 1974 .................................................. .........................................80 dba

Amended and renumbered Ch. 558, Stats. 1977. Effective January 1, 1978.

[Software Guy]

Thank you for your reply.

I should have clarified that I would like to keep the exhaust noise as close to stock as possible. I live in a close-quarters condo complex and don't want to upset my neighbors, and I don't want to attract more attention from the local PD or CHP than I already do driving a sports car.

FYI--I found this on the web. It's a CHP web page that contains enforcement guidelines for exhaust noise.

http://www.cent-21.com/laws/exhaust-us.htm

FWIW.

[Andy O'Hara]

Thr rule of thumb I used was to stand at the driver's door while the driver lightly stepped on the gas. If the engine was the main source of sound, fine. If all the racket was coming out the tailpipe, obviously the "muffler" wasn't doing its job.

From there, a quick exam to decide if it was defective or modified. I loved writing those. Wish I still could--they come through here at night setting off all the car alarms.

I've never understood, I guess, why someone wants their itty car to sound like a John Deere tractor.

[SB 405]

Forget the cars. I'd suggest going after some of the motorcycles on the road. I can't believe how loud some of them are.

[Fire1]

The first question is why do you want more exhasut noise. If you are not racing the car, then you do not need the small increase in power that an exhaust "might" give you (and even if you are racing, the car should not be on the road) All it does is give us an extra excuse to pull you ever. I never go by the decible rule. I have people all the time give me certs from the state referee stating that their exhausts are "legal" and under the noise maximum. I say "sorry, sign here" on their cite for 27150(a)VC. If i think it is too loud, its too loud. If i can hear your car as you pass me on the freeway with my windows closed, then you are getting a ticket.

[TheForceCHP]

If you are trying to stay legal then only buy a CARB/ARB certified cat-back exhaust and also put the provided sticker in the proper place

[PapaBear]

Thank you for your reply.

I should have clarified that I would like to keep the exhaust noise as close to stock as possible. I live in a close-quarters condo complex and don't want to upset my neighbors, and I don't want to attract more attention from the local PD or CHP than I already do driving a sports car.

FYI--I found this on the web. It's a CHP web page that contains enforcement guidelines for exhaust noise.

http://www.cent-21.com/laws/exhaust-us.htm

FWIW.

And, sir, FWIW, your post has this inclusion:

Enforcement Guidelines

The only drivers who should be cited are those whose vehicles:

1) are not equipped with a muffler

2) clearly emit an offensive, harsh, excessive noise, or

3) have a clearly defective exhaust systems (holes, leaks, etc.)

That means, if an officer who has stopped you considers your exhaust is emitting "...an offensive, harsh, excessive noise..." you may get a ticket! Clearly, the references I offered you are the law. If you were to replace your exhaust system with a lawful system that does not emit a noise as indicated above, there would be no need for an officer to stop you and examine your system. The law is clear! Abide by it or reap the consequences of your actions.

A final note to you is this: if you are going to ask a question within this forum, ask the question and await the answer(s). DO NOT argue with the respondants or attempt to qualify your reasons for wanting to disregard the law. If you are looking for us to support your actions, you will be sorely disappointed.

[Software Guy]

The first question is why do you want more exhasut noise. If you are not racing the car, then you do not need the small increase in power that an exhaust "might" give you (and even if you are racing, the car should not be on the road) All it does is give us an extra excuse to pull you ever. I never go by the decible rule. I have people all the time give me certs from the state referee stating that their exhausts are "legal" and under the noise maximum. I say "sorry, sign here" on their cite for 27150(a)VC. If i think it is too loud, its too loud. If i can hear your car as you pass me on the freeway with my windows closed, then you are getting a ticket.

Again, my intent is not to make my exhaust louder. If I can find an exhaust that is quiet enough to meet my criteria for (a) not upsetting my fellow condo tenants and (b) not attracting you guys :) then I will buy it.

I have no intention of making my exhaust louder for the sake of making it louder. That would be just stupid.

[Software Guy]

And, sir, FWIW, your post has this inclusion:



That means, if an officer who has stopped you considers your exhaust is emitting "...an offensive, harsh, excessive noise..." you may get a ticket! Clearly, the references I offered you are the law. If you were to replace your exhaust system with a lawful system that does not emit a noise as indicated above, there would be no need for an officer to stop you and examine your system. The law is clear! Abide by it or reap the consequences of your actions.

A final note to you is this: if you are going to ask a question within this forum, ask the question and await the answer(s). DO NOT argue with the respondants or attempt to qualify your reasons for wanting to disregard the law. If you are looking for us to support your actions, you will be sorely disappointed.

As to the law regarding loud exhausts, we are in perfect agreement.

Perhaps there was a misunderstanding regarding your last statement, sir. I published the URL to this web page to support your statements of the vehicle codes. I apologize if I seemed argumentative.

[Fire1]

I am just going to throw this out there. I am going to agree with PapaBear here but also say something. You really seem to be fishing here. All your posts have had to do with speeding, engine modifications, racing motorcycles, and bad officer behavior. While it is ok to have questions, your purpose here seems to be more than just seeing information.

I am just going to leave it at that. If you get my point, then good. Otherwise, you might find yourself at the end of increasingly negative post responses (or none at all).

[Software Guy]

I am just going to throw this out there. I am going to agree with PapaBear here but also say something. You really seem to be fishing here. All your posts have had to do with speeding, engine modifications, racing motorcycles, and bad officer behavior. While it is ok to have questions, your purpose here seems to be more than just seeing information.

I am just going to leave it at that. If you get my point, then good. Otherwise, you might find yourself at the end of increasingly negative post responses (or none at all).

I get your point clearly, Fire1. I own my behavior that I may have fished or dissed officers. That said, I do not have any negative motives--I am simply socially clumsy and unaware of people's feelings like a lot of engineer types are. I hope you and others understand. I will endeavor to be more aware of my behavior, the rules, and the professionalism of the CHP in the future. Thank you.

:doh:

[dw]

Give the guy a break, guys. This is a public forum and the topic is Legal and Enforcement. Though this topic doesn't have a whole lot of activity, these questions and discussions are exactly why I created such a forum.

CARB/Emission modifications are one of the most complicated subjects to interpret -- there is a reason we've had specialized training dedicated to the subject. He asked a legitimate question and then cited one of our own Information Bulletin's. (I don't think the IB was intended for public distribution, but it is not a confidential document and is easily accessed on the Internet.)

I too question why a software engineer would want to modify the exhaust on his Honda, but the fact is that this is America and if he wants to do so in a legal manner, who gives a flying f%&^? I somewhat sympathize with Software Guy having engineers as friends most of my life; they think differently than most. The fact is that there are hundreds of laws that are written and/or enforced with substantial gray. The sentence "Clearly emit an offensive, harsh, excessive noise," is substantially gray and I don't see a problem discussing it.

We have good reason to skeptical of Software Guy's intentions based on the totality of his posts, but this is an Internet discussion forum and not the road. I have yet to see anything other than an inquisitive mind and (and I mean this in the most endearing way :wink:) some social awkwardness typical of his claimed profession.

I don't see anything in this thread that would constitute Software Guy arguing and I don't agree the law (or at least the IB) is as clear as some have claimed.

[Software Guy]

Sorry for all the mixup.