Exhaust loudness testing

[Hot Rod JayRad]

Hey,

So I wondering how teams have done the exhaust loudness testing on thier own, before going to comp, and how accurate its been in relation to the equipment tech uses. Is there cheap equipment that will get the job done? Last time, we barely made it, and I want to make sure our new muffler meets regs.

Thanks!

[Hot Rod JayRad]

Hey,

So I wondering how teams have done the exhaust loudness testing on thier own, before going to comp, and how accurate its been in relation to the equipment tech uses. Is there cheap equipment that will get the job done? Last time, we barely made it, and I want to make sure our new muffler meets regs.

Thanks!

[Dallas Blake]

Our school's health and safety department has a decibel meter that we use. However we consistently have problems passing noise so I don't have a great deal of faith in the tester we currently use

[jsmooz]

Radioshack decibel meter works good for us. Ours is spot on to an expensive calibrated unit the same as they use a competition at the fraction of the cost.

[Nitesh]

Nokia 3250 http://fsae.com/groupee_common/emoticons/icon_biggrin.gif
we didn't check noise before and had problems at the comp. when working on the noise we used the phone to check the noise levels. atleast got us through

[drivetrainUW-Platt]

We have own Decibl meter, but our car was fine on it in the pits and didnt pass tech when we ran there....they are hit and miss, plus or minus 5 dec I on ours I would estimate.

[BeaverGuy]

Testing the noise level of the exhaust isn't trivial. HOwever, if your meter can measure peak A weighted fast averageing and has an ANSI 1.4 Type 1 or Type 2 or the comparable European rating then it should perform perfectly well for verifying exhaust sound level. However, it must be calibrated and not just with the internal calibration if the device has one.

In '05 we measured sound at our pit, it passed and then we took the car to be checked. The reading was higher at the event and the car didn't pass. So the car came back to the pits and we immediately tested it again. The car had acceptable noise levels. So they guys took the meter to the testing station and they were kind enough to let our crew cheif measure cars along side the tech inspector. After the first one gave different readings they used their calibrator on our meter and calibrated it for us. After that our meter and the official meter read the same.

So, if your meter gives a good reading and you don't pass because the official one says you are too loud then your meter needs calibrated. Bruel & Kjaer sells a real nice calibration unit, B&K 4231, that is small, lightweight, and easy to use. It seems like it only cost $400, which I would consider reasonable for a team that has been around 4 or so years, when I bought one for our company last April but it might have been $900 in which case it is probably too expensive for even the most established teams to justify.

[Superfast Matt McCoy]

No need to test, just make it work the first time.

http://sae.ou.edu/muff.bmp

And safe, too.

[skillet]

wow you must have lots of free time.

[Wesley]

I suppose we can reveal our secrets for passing noise tech...

http://photos-480.ak.facebook.com/ip002/v66/181/98/9619773/n9619773_33252480_8678.jpg

[Yellow Ranger]

Damnit Wes, giving away our secrets again, at least you haven't hinted at our new fancy cross-drilled brake lines- opps...

[Sooner_Electrical]

Hey, I know you're new members, but stop giving away the secrets! Next you'll be blabbing on about our rotary exuberator! Dammit! Don't even get me started on the Kanuter Valves. I am sure by now that these fine people know we buy most of our critical parts from

http://kalecoauto.com/

... If we lose this year we all know why.