s30kid Posted April 26, 2012 Share Posted April 26, 2012 280z Twice Pipes, California street legal? California smog legal? Are they too loud? I have a 1977 280z and would like to have twice pipes on my car. I have a 3-2 header sitting in my garage and i want the twice pipes to go with it. would there be any significant horse power increase? I know they sound amazing, but will the local cops think the same? I'm near San Diego, anyone in the same area have any trouble with loud exhaust? Are they strict on it? Quote Link to comment Share on other sites More sharing options...
Josh280z Posted April 26, 2012 Share Posted April 26, 2012 I don't live in CA but I'm pretty sure that it won't be legal. Somebody else step in to help. From what I understand, if your car is a 1976 or newer, they will you on just the visual during the smog check for that that header. Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted April 27, 2012 Share Posted April 27, 2012 No it won't be legal, but can you get away with it? yes as long as you don't drive like a jackass. HP increase? no if you didn't do anything else to the system you probably wont be getting anything (unless your current exhaust has rust build up blocking flow) I had a 3" straight pipe to a turbo muffler that was loud as an elephant and I passed cops many times going speed limit without problems. On another note I did get pulled over in my 280zx for a "modified exhaust" but I had Florida plates and the guy just let me off with a warning since he didn't want to do paperwork I think. This was in SoCal. Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted April 27, 2012 Share Posted April 27, 2012 On that old of a car, 1977, you have smog to deal with still, but as long as it is after the catalyst you should be fine. As far as noise I would bet with the catalyst in place it would quite enough to pass a sound check. They only hickup you may face is the BPT for the EGR. If you dont have enough back pressure in the system the EGR will not function and constitute a failure. The way that system is checked on your car though, it will pass an emissions functional check as all they do is connect vacuum to the it and cover the exhaust to simulate back pressure. In short it will still pass. As for the header you will need one that is Ca legal. The Catalyst has to remain on the vehicle within 3" of its original location. Other than that I do not see why you would have an issue. Technically speaking its illegal. The law is written to the tune of any modification from the beginning of the emissions system to the end that is not approved is illegal. That said the loop hole is that you cannot purchase an original OE cat back exhaust system for the car. So who is to say you cannot replace the exhaust pipe and muffler with something else. This would ONLY be an issue if you were sent to a Ca ref though. A smog station is not gonna flinch over it as long as the header has CARB or EO numbers and the catalyst is in place. Quote Link to comment Share on other sites More sharing options...
s30kid Posted April 27, 2012 Author Share Posted April 27, 2012 Do you know when the smog limit is going up? I heard that within the next year a bill will hopefully pass saying cars 1980 and older wont need smog. Is this true? Quote Link to comment Share on other sites More sharing options...
Tony D Posted May 7, 2012 Share Posted May 7, 2012 Thing is, I don't know of any headers that are CARB listed. There was, under the pre-CARB days the simple requirement that as long as the headers retained all smog fittings, they would pass. Then the rules said you had to go through CARB testing. Most existing header makers for the Z-Car didn't want to bother with the new testing and sims dropped "smog legall" headers for the "not Ho be used on any pollution controlled vehicle" or " Not legal for sale in CA on Any pollution-controlled vehicle " Good Luck! Quote Link to comment Share on other sites More sharing options...
johnc Posted May 7, 2012 Share Posted May 7, 2012 Don't expect any changes in the model year exemption from smog testing. Quote Link to comment Share on other sites More sharing options...
yhlz Posted June 29, 2012 Share Posted June 29, 2012 Just incase you were still wondering, I believe that it can not be louder than 94dB. If your car came with a catalytic converter, it is also illegal to remove it. Quote Link to comment Share on other sites More sharing options...
ctc Posted June 29, 2012 Share Posted June 29, 2012 280z Twice Pipes, California street legal? California smog legal? Are they too loud? I have a 1977 280z and would like to have twice pipes on my car. I have a 3-2 header sitting in my garage and i want the twice pipes to go with it. would there be any significant horse power increase? I know they sound amazing, but will the local cops think the same? I'm near San Diego, anyone in the same area have any trouble with loud exhaust? Are they strict on it? There are CARB legal twice pipe cats out there. Run the stock manifold into a 1-2 splitter, when you need to hit the smog station. Then swap back to the header. As stated the header will never be CA legal, but you can get the cat and everything behind it to be. Quote Link to comment Share on other sites More sharing options...
kaito Posted June 29, 2012 Share Posted June 29, 2012 I think you will be fine with the cops as long as you have something that says e.o. and exhaust on the same paper. CA cops are stupid. I also had headers and a straight pipes on the flattop motor and it was loud but I never got pulled over. This was in san diego, but in the cops defense my car looked like it was falling apart. Quote Link to comment Share on other sites More sharing options...
johnc Posted June 29, 2012 Share Posted June 29, 2012 You may be fine with the cops, but you won't be fine with the smog techs. Especially after the STAR program is fully implemented. Quote Link to comment Share on other sites More sharing options...
8DC Posted June 29, 2012 Share Posted June 29, 2012 Does anyone know how many decibels the twicepipes system with header puts out while cruising? Under moderate acceleration? Idling? Would be good information to have if anyone has access to the instruments used to measure such things. Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 30, 2012 Share Posted June 30, 2012 Does anyone know how many decibels the twicepipes system with header puts out while cruising? Under moderate acceleration? Idling? Would be good information to have if anyone has access to the instruments used to measure such things. For people in CA, it's easy to know if your car passes if you have the sound meter app on your smart phone --- you can read the procedure in the the CVC and set up the test yourself. Easy Peasy, Lemon Squeasy! Quote Link to comment Share on other sites More sharing options...
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