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Being Sent To Epa, What To Do With Current Exhaust?

S3RK

By S3RK,
in Engines & Forced Induction

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sydking Veteran

sydking

Posted
Posted

"... the vehicle bearing Registration Number XXXXXX is excessively noisy and therefore likely to be exceeding the legal noise levels for the vehicle..."

"The noise test and anti-tampering inspection must be undertaken by an EPA approved Mechanic by the compliance due date which is Wednesday, 23 May 2012"

"- the engine test speed for your vehicle is 4800 rpm and the legal noise level for your vehicle is 90 dB(A)."

Again, I have a stock standard RB25DE with a K&N high flow panel filter, and a 2.5" exhaust system with a high-flow cat and 1 resonator + cannon (Will replace shitty cannon with twin tip muffler, hoping for less than 90 dB), stock extractors.

Will that pass the test? I'm just curious about the 'anti-tampering' part of it. Is a high-flow cat considered to be 'tampered' with?

Thanks.

got the exact same thing, Get a flage made up and put behind cat with steel wool stuffed in, I did and i passed at 1 DB under

Too easy.

Miguelone Grand Master

Miguelone

Posted
Posted

Get a stock GTt rear muffler (assuming the pipe joints are in the original location). Plenty of flow for an RB25DE and quiet.

I was gonna say have you heard a gtst system on an na 25 but then I saw you said rear muffler. In which case probably a good way to go.

kaitoukid Veteran

kaitoukid

Posted
Posted (edited)

Woot, also an EPA letter in the mail for me. Zzzz. To avoid making a new topic, going to post here. Unless I get no replies... in which case I'll have to make a new thread :P.

Similar to OP; think I've got a 3" catback with huge canon (kakimoto), possible hi-flow cat (not sure). Lols (Yeah, I'm one of those). In my defense, it was on the car when I got it down from Japan, and I was initially too lazy / no monies to swap it over; and then I just got used to the sound (or maybe I just lost some hearing LOL).

What are the chances a custom made 2.25" or 2.5" mandrel bend mild steel catback, with one (or two?) centre mufflers, and a twin tip muffler of some sort; will come in under the legal limit of 90dB?

Whilst hurting my ears, I enjoyed my stupid loud exhaust sometimes in tunnels/under freeways/general spirited driving. But now that I have to change it; I figured it's high time I get the exhaust I was meant to do all that time ago when I first got it haha.

Obviously it's got to pass EPA first though, and I don't know if I can be bothered getting a stock one just for EPA, then swapping over to one I get made up. Would be better if it's possible the one I get made up is legal in the first place...

Cheers for any help brahs.

Edited by kaitoukid
Captain Natro Grand Master

Captain Natro

Posted
Posted

i get tired of helping sometimes... nevertheless.

a 2.5 inch mild steel system with a twin tip and two center mufflers/one center and one resonator id.imagine would.come close to legal.... in saying that mines gota twin tip nd a resonator and its not even close to legal noise. hope this helps...

at the end.of.the.day if its too loud people are just offended by the noise/sound, better off having it sound nice then loud.

kaitoukid Veteran

kaitoukid

Posted
Posted (edited)

Haha, I'm pretty over just loud. But reluctant to make a full-time switch to stock; ideally would get one that sounds nice as well as being under the legal limit. The reason I asked straight away about that system is that's the one that's more or less recommended over and over; which I was initially going to go get ages ago anyway; but would prefer to hit two birds with one stone (change over AND clear EPA).

Just wanted to know if people thought it was possible, haha. Yeah would've thought the two mufflers would help (as well as no canon lawls) keep the sound down, but down enough is the question.... Might have to just swap over to stock for EPA and then change later; or see if there is a way to (properly) make it under the limit. Either way probably a good time to swap over from my current set up, want the next to be quieter.

Edited by kaitoukid
S3RK Community Regular

S3RK

Posted
  • Author
Posted

In regards to my car, it passed by a good 4db @ 86db. So I was all sweet, then he got it up on the hoist and started taking pictures, seeing the high-flow cat, he didn't care less about it and let me off with it :)

Costed $200 to get the EPA muffler on, will be getting something else done tomorrow that shouldn't sound too loud, I'm hoping for a nice tone. Being a N/A, are they generally louder than a T with a similar setup?

34GeeTeeTee Grand Master

34GeeTeeTee

Posted
Posted

Why would they take pictures? Does it stay on file incase they get you again for the same thing?

I am pretty sure my 3" system would pass the noise test as its pretty damn quiet but its going to restrict power i think.... I was going to look at a bigger system but with size i assume comes noise :/ BUT will see how the current one performs before i go replacing anything i guess.....

Captain Natro Grand Master

Captain Natro

Posted
Posted

yer mate natros are always going to beloude then their turbo brothers due to the design of how turbos work.

because their driven by exhaust gas and bolt directly in the flow of the gas (read noise :P) it acts as a muffler in the system.

In regards to my car, it passed by a good 4db @ 86db. So I was all sweet, then he got it up on the hoist and started taking pictures, seeing the high-flow cat, he didn't care less about it and let me off with it :)

Costed $200 to get the EPA muffler on, will be getting something else done tomorrow that shouldn't sound too loud, I'm hoping for a nice tone. Being a N/A, are they generally louder than a T with a similar setup?

AngryRB Grand Master

AngryRB

Posted
Posted

I found the best muffler for sound reduction was my fujitsubo 3 1/2inch cannon with silencer inside, it was virtually silent idling, and looking round import wreckers 90% of mufflers had the silencer in them too, all Jasma complient

Now i have a 3inch Oval muffler which isnt annoying loud, sounds quite good but probably over 90db,

It really does come down to the pipe size, If a turbo skyline can make 250kw with a 2 1/2inch silencer, then a 2inch is probably heaps for the little power an NA will ever make, and alot quieter too.

2inch might actually help make more power cause im pretty sure you need a bit of backpressure with a NA motor.

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