legal limit is 95 db, wondering how loud that really is. running tri-y headers with 2.5 inch exhaust with turbo tube mufflers on a 347 stroker with 10.8 to 1 compression. have to get my car tested next week & i'm kinda worried.
95 db is pretty loud, Im sure you'll pass. Make sure they test it with a standard of sorts, outdoors at 50 or 100 feet from the outlet of the tailpipe. Some are WOT drive bys at 50 feet away. Sometimes it'll get done inside and the db is raised with all the reverb. ASk them to see the law first and if it isnt clear cut with specific db @ a specific distance then tell them to stand at 100 feet and test it haha!
I actually do acoustic testing for work. 95 db is VERY loud for a car. However, the distance makes a huge difference. Why do you have to get your car tested?
I had my Harley tested last year it has stock headpipes with aftermarket slip on mufflers. they test at 12 inches away at a 90 degree angle 2500 rpm it was 101db now as far as harleys go I would say mine is about middle loud there are a lot of them that are way louder. A v8 with a mild cam and open headers would be louder than my Harley.
ive never heard of Db testing, heck if they did something like that here not many of my buddies cars would pass. i dont know how loud 95db is but my Falcon would give me a headache sometimes when i would drive home from work after a hard day. it was a 302 with 12.5:1, humongous solid roller cam, severely ported and polished set of trick flow heads, and 3" exhaust with single chamber flows and turn downs before the axle. it also didnt help that it was a 4 speed and 4:88 gears and absolutely no interior but the 2 seats and a 10 point cage. sometimes the reverb in that car was so bad that it would distort your vision (my wife would never ride in that car). i kinda miss it because it was a fun little street car but i love my shoeboxes more. and the only thing i can hear is the air blowing from the A/C vents.............and a little bump from the cam.
Try advancing the ignition timing.This will take the laboring sound out of the engine. Take a timing light with you if you have to travel very far to the test and just stop before you get there and jack the timing. Play with it in the shop to find the sweet spot at 2500 rpm and record were it needs to be. Set it before you go to the test and you'll be ok>>>>.
I am running headers, 2.5" pipes, and turbo tubes that turn out in front of the rear wheels on my 56 Chevy. Its got a severely clapped out 350 with a 144 Weiand blower. I have never heard anything that sounds like turbos tubes.....ever. They are slightly obnoxius at low speeeds, but on the pedal, cover your ears. You can literaly hear my hotrod for miles. You might do better to hang a set of mufflers on it for the test. I really doubt I could pass any Db test, at all, ever. Good luck
We're supposed to have db testing done here as part of the modified car (eg hot rod) registration purposes. There's a diagram of where the mic has to be, how high off the ground, how far back and so on. I think the limit is 94db from where the reading is taken. Plenty of guys have done stuff to the exhaust to make sure they get the box ticked (checked for Americans) the the "baffle" is removed.
Spent many years battling with db meters and getting banned from race tracks but I did learn a few tricks that helped. 1. Make sure the car is fully warm before you get it tested. 2. Ensure that the meter is the full 12" away from the exhaust. 3. If your exhausts have a turn down covert them to a straight pipe, the sound bouncing off the ground increases the db reading. 4. Get the car tested on the back of a trailer. Sounds odd but I got bored unloading the car to fail a db test and then having to load it back on again so got them to test it before I unloaded. Passed everytime. 5. Dont know how practicle this one is but carry a bit of old carpet and put it under the tail pipe. I think even the guys that used to test me got bored with failing the car so I was allowed some 'licence'. As I said this was for a track based car so how practicle or relevant some if it is for a street car is debatable. Might give you some ideas of how to pass though. P.
Dont test it on a rainy day. The wet blacktop will make the Db meter read a lot higher. The angle of the pipe to the ground makes a difference too.
I borrowed a meter from work to check out the flatty with just the open pipes fitted and it was 128 db wich was just too loud to drive any distance. I then fitted some small baffles up the pipes and the reading went down to about 95 db which is fine. This is the setup
Years ago we were faced with a new noise regulation at the track. Everyone had to run mufflers and they had a whole page of test procedures for us to follow if we wanted to "pre-test" our race cars. I ended up buying a db meter from Radio Shack and we dialed in the car according to the outlined procedure. It wasn't a big deal but the race car wasn't too loud in the end, actually it could have been street driven I think. Anyway......the race track has since bit the dust and they have developed the property it was on..........we still have the race car.
i used to drive around with straight pipes everyday, never got a ticket. got sick of the noise, & girls complaining about riding in my car so i put the mufflers on. got 2 loud exhaust tickets here in sb with mufflers! car really isnt that loud, i actually got the station officer to sign off one of the tickets, but the tickets are not correctable anymore. i keep getting hit with 27151 tickets. they arent fix it tickets anymore, & they are a point on your record each time. cant afford this shit. going to a smog referee next week to get the car decibel tested. hoping it falls under the legal limit so i can take it to the judge & get the cops to leave me alone. kinda pisses me off, both tickets were blocks away from my house, theres homeless people making & selling meth a block away, & prostitutes 2 blocks away the other direction, but i'm the big criminal driving my car!
I dunno Man, Maybe if you "Lightened" yer skin like Michael Jackson you would fit in better up there in Yuppie Ville On a serious note......... I read somewhere that the Db test was to be done by CHP in a "CONTROLED" environment. Said the car had to be placed in an open area with NO obstructions.. Such as Phone Poles, Trash Cans, etc... I would call CHP & ask to see the legal garb the have written in the books to get an accurate reading.
its a legal chp testing station, actual california smog referree. we'll see how it goes i guess. they arent very fond of michael jackson here anymore either, so they might be on to the whole lightened skin thing! fucker.
back in the early 80's Fremont Ca was well known for hassling people in modified cars. I had a Datsun pickup with 2" pipes and glass packs. one day I tached it up a bit with a cop in earshot. he got out his Sun dwell tach and decible meter and went to work. 95 DB at 2500 RPM was the limit. I was like 97 DB, but his hand held Sun tach did not match the RPM's of my Sun Tach on the dash. he ended up giving me the benifit of the doubt and let me go. I can't believe a noise ticket is a point on your record. that's about as stupid as getting a ticket on your bicycle and having it go on your driving record.which is also true
don't know if they still do ,but radio shak used to sell a d.b.meter relatively cheap i think.or was that a dream? worth a check
If this is a static test (not moving) based on RPM, use the lightest oil you feel safe, hottest plugs, ignition all in by test speed, hot thermostat, turn off your electric fan or use a mechanical with fewer blades, kill the alternator field lead, remove the fan shroud. Attach as much carpet, fibrous material etc. as you can to the floor from underneath, especially hanging down vertically between the muffler and the door.
I entered a muffler rapping contest one year at Sled Scene East and my 52 Buick tested at 121 decibels. (455 Buick powered). That wasn't loud enough to win.
officially no but did get a pulled over and loud exhaust warning with our 60 chev pick up .. stock 6..Fenton split exaust with steel packs out the rear duals... on the way home from having the exhaust system installed.!!!! its loud like a chainsaw...
well had the car tested today, failed pretty bad! 107-105 decibels. they tested each pipe individually, at 3000 rpm's.
Ha Ha...what if your exhaust points UP?! I think my car is too loud when I get into it (anything above an idle, really)...but DirtyT says it's fine!! I guess I'll know once I start driving it! (Don't know if they do decible testing here, but if their meter is on the ground and the exhaust points at the sky...will that make for an easy pass???!!)
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