Clearing EPA, how do they usually test it?

**lemmiwinks** · 31-07-2011 11:21 AM

So I got EPA'ed last night and wanted to know how they test the loudness of my car.

How high do they rev the car to obtain the db reading?

Car in question is a DC5R, toda headers with a mugen twin loop. Factory DC5R does not allow you to rev the car past 5k rpm while being stationary. So I was wondering if I would fall under the limit if I took my car to a tester as it is at the moment, without reverting the exhaust system back to the standard one.

According to this youtube video, the mugen twin loop exhaust is pretty much the same volume as the OEM exhaust.

**trism** · 31-07-2011 11:26 AM

if you did a quick google seearch, im sure youll find the answer. its not like youre the first person to ever ask this question

**trism** · 31-07-2011 11:27 AM

http://lmgtfy.com/?q=exhaust+noise+test

**Lukey** · 31-07-2011 11:32 AM

they set up a microphone thing on a stand about 30cm from ur exhaust tip and rev it to a certain rev and and get a noise level on there little computer jigger connected to the microphone.

personally i think ur better to go back to stock as it costs money to get it tested.

you also cant do it on a rainy day either

**lemmiwinks** · 31-07-2011 11:43 AM

Originally Posted by trism

if you did a quick google seearch, im sure youll find the answer. its not like youre the first person to ever ask this question

Already tried googling it and searched on ozhonda. Can't find anything in regards to my stock ecu having a rev limit of 5k rpm while being stationary, So would they just test it at 5k rpm?

Originally Posted by Lukey

they set up a microphone thing on a stand about 30cm from ur exhaust tip and rev it to a certain rev and and get a noise level on there little computer jigger connected to the microphone.

personally i think ur better to go back to stock as it costs money to get it tested.

you also cant do it on a rainy day either

You wouldn't happen to know what revs they conduct the tests at would you? Do they test it at a certain percentage of the redline revs?

**dc2r-0636** · 31-07-2011 11:49 AM

its tested at 75% of where it makes its peak power

easy example would be a car that makes peak power at 10,000rpm would be tested at 7500rpm,

**Lukey** · 31-07-2011 11:51 AM

it varies from vehicle to vehicle. mine got tested at 4750rpm

they will also have a look at ur exhaust system and make a small diagram on it aswell

**mugen_ctr** · 31-07-2011 11:52 AM

they rev to 5000RPM if the vehicle is made from 1989 onwards if i recall.... though since u say dc5r cant rev to that whilst stationary, than im sure they will just rev it to what ever its limited to id assume....

To be safe, get a independent tester, to test the Mugen twinloop to see if it matches with the video, or else ur gonna have to go back to oem exhaust to pass....

Or if u want a easy pass, just go oem all the way, swap the cat back over later on... the headers u can keep, as it doesn't effect noise so much.

Just to give an idea, on my car, reved to 5000rom, i hit 87db! on stock system lol, bit high but i passed

**trism** · 31-07-2011 12:10 PM

Originally Posted by lemmiwinks

Already tried googling it and searched on ozhonda. Can't find anything in regards to my stock ecu having a rev limit of 5k rpm while being stationary, So would they just test it at 5k rpm?

You wouldn't happen to know what revs they conduct the tests at would you? Do they test it at a certain percentage of the redline revs?

are you serious? did you even look at my link? all your answeres are in the first result!!!

**lemmiwinks** · 31-07-2011 12:33 PM

Originally Posted by mugen_ctr

they rev to 5000RPM if the vehicle is made from 1989 onwards if i recall.... though since u say dc5r cant rev to that whilst stationary, than im sure they will just rev it to what ever its limited to id assume....

To be safe, get a independent tester, to test the Mugen twinloop to see if it matches with the video, or else ur gonna have to go back to oem exhaust to pass....

Or if u want a easy pass, just go oem all the way, swap the cat back over later on... the headers u can keep, as it doesn't effect noise so much.

Just to give an idea, on my car, reved to 5000rom, i hit 87db! on stock system lol, bit high but i passed

I'm probably just going to revert everything back to oem just to be safe.

Originally Posted by trism

are you serious? did you even look at my link? all your answeres are in the first result!!!

Yes I did read that, but I'm still not certain what rev's they would conduct the tests at. 75% of my ESMP would be 6075 RPM, however the stock DC5R ecu does not allow you to rev past 5k rpm while being stationary. More interested to know if someone has been in a similar position where their car could not rev to 75%.

Code:

Where the ESMP for that engine has been determined by the testing
authority the engine shall be brought to and stabilised at a speed as close to
¾ ESMP as the testing officer can achieve;

**TheSaint** · 31-07-2011 01:45 PM

Originally Posted by lemmiwinks

I'm probably just going to revert everything back to oem just to be safe.

Yes I did read that, but I'm still not certain what rev's they would conduct the tests at. 75% of my ESMP would be 6075 RPM, however the stock DC5R ecu does not allow you to rev past 5k rpm while being stationary. More interested to know if someone has been in a similar position where their car could not rev to 75%.

Code:

Where the ESMP for that engine has been determined by the testing
authority the engine shall be brought to and stabilised at a speed as close to
¾ ESMP as the testing officer can achieve;

you wont have to revert everything over ... its only the muffler that will make the system loud
can you unbolt the axel back and bolt on your OEM muffler?
that would be the easiest solution

from memory a stock Dc2 will only just pass the test lol

**lemmiwinks** · 31-07-2011 06:58 PM

Yeh, I've still got the oem muffler which I will bolt back on. Although the mugen twin loop would probably fall under 90db at 4-5k rpm anyway. Always good to be safe