Exhaust Issues

[cheez]

hey guys

just want some opinions on how i can quiten my exhaust without having to change to standard so that it passes the epa test for noise pollution?

i've had it tested by 1 of their recommended repairers and it came in at 100dB. i put my modified silenceer in and it went down to 93dB. What else can i do to dull the sound a bit more?

cheers

daneil

[Adriano]

I use some 2mm steel plate with lots of 6mm holes drilled in it to go in between the flanges, just put lots of stainless steel pot scourers in front of these, should do the trick, but t he car will run like crap, so i wouldn't boost it.

[evlgtr]

hi

im getting sent to the same pleace EPA for sound and polution and i will put in that 2mm plate in between the exaust,

but make sure that the 2mm plate is welded to the exaust if its not they will not pass it

(Weld it only in 4 corners so it is easy to take it of again)

(make sure that you havent got a aftermarket computer or chiped and that you havet got a boost controler)

glad i can help

Alex

[R31Nismoid]

Note... putting a plate in is illegal.

Now carrying on... spend the money on a decent system and you wont have the problem

There are many brands that come virtually smack onto the noise restrictions.

Look at additional mufflers, its the only way

[saliya]

Hey,

To shut it up and get it passed a drilled plate might work (either welded in, which is perfectly OK,

or removable-but-nobody-knows-its-there, which isn't).

The problem is that everything is supposed to be part of the exhaust (not removable). So your silencer (I'm

guessing you mean one of those things jammed in the tailpipe) is supposed to be welded in; and any plates

should be welded in. Anything removable will probably be removed before measuring...

The bad news is that when you remove the silencer and plate (you will, because the car will run like a busted ar5ehole),

you will probably get pinged again; this time, they will probably hit you with a big dollar fine straight away...

The good news is that if your pipework is 3" or smaller and you have stock cams/turbo it should be relatively easy to

legalise properly. A working cat, a centre straight-through resonator/muffler, and a rear straight-through muffler of

reasonable volume should allow you to get below the legal limit easily (and it will sound good too ).

If you have more lift/duration/overlap on the cams, or a bigger turbo, or bigger overall pipework you will need more muffling

to counterbalance that. 3.5" pipes are borderline but probably OK with stock cat/turbo/cams; for 4" pipes and aftermarket

turbo I had to use a rear muffler that was not straight-through.

It will be cheaper in the long run to do it right the first time... and no, you don't need to go back to stock to do it...

Regards,

Saliya

[cheez]

i have a 3.5" kakimoto cat back. stock cat, front pipe and dump. turbo is running 7psi (used the solenoid grounding mod on it). the silencer sits right back into the exhaust almost invisible as it it a piece of pipe with a welded flat circle so its hard to see it.

thanks for the advice guys. think its just easier to put stocky zorst back on, pass the car and then just always run the silencer to stop cops picking on it all the time.

just 2 add, this will be my 3rd visit there, first 2 for pod and cooler conflicts.

[mattymagoo22]

whe you get your car checked by the epa they have to use the decibelmeter 1 meter back on a 45 degree angle half a meter off the ground. So when you get your car tested rev the engine slowly (they'll test it at idle and at 65% of maximum engine revs I think) bring them up to the specified limit and then let it down slowly as this will make your exhaust sound quieter (jam your foot on and then let it straight off) every little bit counts.

I've also heard that putting on a droopy tip on your exhaust can also knock off 3-4db, and due to the nature and position of the test and meter I'd believe it as it would have to bounce the sound off the ground up into the meter rather than coming straight out at it.

Hope this helps

Cheers matt