At what RPM do EPA test the exhaust note?

[Guest RedLineGTR]

i wouldnt think revving an engine in a stationary position is to good for the engine..assume it will be for a couple of seconds..and i've heard as well that they rev it to about 4000rpm...but what would happend if you had one of those aftermarket tachos from japan that go in the dash where the original one is...like redline at 11,000... :shrugs:

[predator]

so in other words there is no real process, therefore its a bullshit test..

[aybee]

Originally posted by whistla

now iv put the old custom twin pipe back on and if inasnt is saying he got 83dB on a STOCK muffler (which is only 7dB away from limi), i think im screwed!

if i remember correctly from yr 12 physics, an increase of 3dB doubles the sound. So 83dB is twice as loud as 80dB and so on. that means that 7dB under the limit is a lot of noise difference. with stock turbo and 3 inch exhaust, got a good chance of getting under with a silencer. mate of mine did that and got 89.9dB

[aybee]

Originally posted by predator666

Any1 know how much these places charge for the basic test?  

i was told that mr muffler do them for 26 bucks, dont quote me though

[NismoR34]

mine cost $27.50 last year for a basic test.

aybee is correct in saying that 3db is a doubling in sound output - but i didnt learn that in high school. 83db is very quiet compared to 90db.

The human ear can not detect a volume change of 1db either, usually 2db or higher. So another b.s. part of the story is that if your exhaust is say around 90 / 91 / 92db you might get called in for a test but actually pass it without needing to make a change. A cop that hears your car drive passed doesnt actually have a clue what the output is - they just decided that YOU need to pay the govt some more $$$

sux.

[predator]

yer, i forgot the 3db = double the noise rule!! i knew that now you reminded me bet Mr Engineer denham didn't know that - lol. So I could be fine.

My car was pulled over and and the car would have been driven gently because i wasn't driving it, not even thrashing it to redline (like i do).. the cop was just being an asshole (as they do) and making life difficult (as they do). Unless the cop carries a CO^2 meter, then he has basically no idea and just does it to annoy you ..

The EPA test is actually free, so if anything the cops are wasting the EPA's time - when they should be more actively going after 95% of where the pollution is, and that is industry and older smokey vehicles... not well tuned japanese sports cars which (generally) have pollution requirements several years ahead of our local manufacturers.

[whistla]

3db = double the noise

THATS RIGHT! argh..totally forgot about that, sorry :S

We did a few tests and got damn close to 90dB

Im gonna wing it and just rock up, see how it goes

For a bit of fun, we tested my mates HQ and got 100dB

[YogiR33]

if u wanna be 100% safe u can borrow my stock muffler mite even bolt straight in !

[whistla]

Thanx Yosh but the stock muffler wont just bolt in..

Ill need to bolt the whole system in, there isnt enough time for it and i have exams to study for

If it wasnt for these f**king exams i would have gone today, no good now

Well see how it goes

[whistla]

Dicks...i failed the test

Passed emissions and all of that (cos i bloody well too everything off)

They knew where to look, theyre sneaky!

I was going to hide my Wolf and put in a mock loom into my facotry computer, but the moment they opened up my bonnet, he disconnects the AFM to see if itll stall

If i hid the Wolf (the Wolf doesnt use the AFM) it would have done anything, and would have been shafted pretty good

Other than that, i failed my noise test

94dB when it should be 90dB

So, im in need a stock cat back exhaust if anyone has one i can borrow, can u please PM me

Cheers

[meggala]

what revs did they check it out at luck you took the wolf out you would have been owned

cheers

[predator]

lol.. just glue the AFM plug on.. say its stuck.. if they try and pull it off and it snaps, go ape at them and charge them for the damage. That would be funny, they'd probably leave you alone then. Actually

Yes, i've heard they are getting wiser in what to look for, but it still doesn't stop the process of what everybody does and that is return it to stock for just the test.

I need to know for sure what level they test the noise at for my test in a couple of weeks - so plz enlighten.

What is the process if you fail the test? do they fine you? When do you have to come back again? What is involved in the 2nd test? They are not very specific in these important details in their damn letter

[YogiR33]

Dude when is the next test ???? u free this friday during the day i'll bring round my exahust for you to hav a look at and see if u can use it, i use to hav it on my car and it was quiet as ! it is the stock muffler !

[whistla]

Yosh, thanx dude...ill give u a buzz, wont be able to do ANYTHING till after monday though cos i have two exams iv gotta get through first before i start with the car

they give me an extra 30days to clear it

the correct and up to date test for the R33 GTSt is 90dB @ 4800rpm

the guys were pretty cool there, had a laugh

theyre more than aware of what we do where we take all the gear off only to pass the test

he laughed at the new bolts here and there and said "just put

these on hey?"

he did admit that its a shame that the RB25 rev so high because the general rule was a straight 6 would USUALLY be tested at 3500rpm but because the RB rev so freely/high its basically 3/4 of the rev range

note: i was under 90db at 3500rpm

the mic was taking roughly 25cm back and 45degrees across from the point of the exhaust (worse for those guys that have the angled exhaust because its directed to it, but youll be a dumb knob if u think youll pass with a cannon)

speaking of nobs, a guy before me actually brought his R33 AS IS with BOV, cannon, bald tyres (not that it makes a difference), intake, etc THINKING he'd get off i suspect

he got 100dB for noise

theres two stages at which u can fail:

1. emission (including intake/ecu/boost/bov/etc)

You fail this, u get a pretty little green sticker on your car, 30days to fix and ONLY EPA can take that sticker off

2. noise test (providing emissions pass)

This is where i was at, they gave me two options...

Get a pretty little green sticker, get the noise fixed, then go back to EPA to test the noise

OR

No pretty little green sticker, but i see to it getting fixed, approved by a tester and fax/mail/hand in the test results providing they pass..then the matter is cleared

i took option two cos f**ked if im gonna make the trip up there again

i passed everything but the noise, only because i put ALL my stock gear on, but thinking my old sedate exhaust would be under

i was shocked

i still had my front mount in, and they duely noted that that was considered my one intake modification

they were cleaver and i was watching their moves...they confidently looked around in the engine bay, under my heatshield for aftermarket turbo, vaccum lines and IMMEDIATLY noted a small wire that make out of my intake pipes

this guy stunned me! i have a temp probe drilled in just before the throttle body for the Wolf to register intake temps and to compensate igintion/fuel

dont take these guys as being dumb farts, cos they looked as though they deal in skylines/vls all their lives and know EXACTLY where to look

ahh well, price we pay really

[Guest INASNT]

shit i forgot u had a wolf with map sensor, coz the first thing they checked on mine was the afm 2! But u couldnt of fixed it anyway, i am surprised u acxtually still have the afm in the engine bay

DOH!

[whistla]

luck for me the Wolf was Plug in and Play

Just took it out, plugged the factory ECU, put the airbox and afm (luck cos i was >

I would have looked at him dumb founded and say "was something suppose to happen?"

[predator]

lol - well it probably has with guys who don't actually know their car had an aftermarket ECU (jettttt )

thanx for the headsup whisla, appreciated. Mine is in 3 weeks.

[whistla]

good luck dude...

pm me if u need any help

[aybee]

a friend of mine took his 33 in for sound test. the guy said rev to 4800 and hold it till i say. then he walked back and set up the his shit. anyway car passed cause was only revved to 2200 odd. quite funny.

[whistla]

They revved the car while the mic was on a stand behind the car