Tried it again inside, even pulled the main breaker in the house, as there was just a hint of the frig running 2 rooms over (and who knows what else that was humming I could not hear). Managed to get it down to 36.
BTW, which app are you using?

What is the lowest you have ever measured, anywhere??

Tried the car again too. Got 74/75 idle (odd it got louder fully warmed up) and 89 @ 2900 RPM (use a long screwdriver against the seat for those that don't have another person around). I also tried flipping the phone around in all different directions, had pretty much no affect.

I'm on stock cams, 9 turbo, megan O2, ported stock mani and turbine housing.

 

I thought "silence" is around 30 dB anyway? I will measure my Greddy Ti later... Should be interesting.

 

I wouldn't really worry about silent and passenger jet loud on a phone app.

From what I have read, most consumer-level db meters are only advertised as accurate for a certain range, say 30db - 120db, etc. I would imagine a phone would have less range than that.

 

Aby,

How are you liking the gsc s2 over the previous cams you had?

 

can you take a picture of your exhaust, especially under the cat to see where the mufflers / resonators sit.

So i recently got into a fender bender & I had a jdm rear bumper installed. the bumper hit my old 7" x 18" muffler, so i swapped that out for the dynomax vt muffler.....only becuase i had to do something quick & I already had it.


***Outside***
94 @ 1200 rpm
xxx @ 3000 rpm

...WTF?! the phone read higher @ idle, but the note is completely different....nowhere as "basey" or "boomy". i will modify the flapper so it doesnt flap so much...

 

Yea I'll try to get some but it will probably be from the side.

 

Can you look inside, does the flapper rattle and or open?

 

yes, it flapped @ idle in dynomax factory form....

quite honestly, that muffler sucks if you have big cams....for me, it actually sounds worse in the car @ 3200 rpm.....

initially @ idle, the car sounded like it had a really bad exhaust leak

so I modified the flapper by eliminating the smaller portion of the flapper, relative to the flapper shaft..... i will get #'s & pics showing the mod later on today.

 

it truly sucks that some of you live in states that care about this type of nonsense or haven't found legal loopholes around the laws as I have. Yes, some of you care about this out of personal preference and the desire for a "quiet" setup, but the rest of you worrying about this due to laws and inspection requirements, etc., I feel for you. Good luck with this little experiment Aby.

 

I too had issues with the dynomax setup. It didn't like my 2.3 stroker with cams . That is why I went with the boost acutated cutout and stock catback.

I did get the rattling under control. I adjusted the wastegate arm that actuates the valve. The rattle is just about gone.

 

will it be quieter to run one of these cats or a second muffler where the cat normally goes? im running a mid magnaflow muffler right now.. looking to go quieter though

 

Originally Posted by Aby@MIL.SPEC
can you take a picture of your exhaust, especially under the cat to see where the mufflers / resonators sit.

These are the best pictures I could take at this time. If you need pictures from directly underneath I can do that but I will need some time to do it. The first 2 pictures are the 7" round muffler that sits in the stock cat location or test pipe spot. The 2 last pictures are the pics of my 12" long resonator.

 

I was bored today and remembered this thread so I just checked out my AMS TBE with HFC for fun. Held approximately 20" away and measurements were made with the Android Smart Sound app (so I doubt this could be considered truly accurate). The car has stock cams.

Cold start idle was 93 db, spiked to 100 when the car turned on

3500 RPM was 100 db

I'm not so sure about the 100 db reading because it sounded pretty damn loud haha I figured it would be a bit higher than that.

Edit - did some research about the 100db reading and it looks like the app just doesn't go past that, not even the pro version

 

I used iPhone app and it only goes to 102 dB. I believe I hit that at idle with my Greddy Ti with Cosworth 272s. I revved and it didn't go any higher.

I wonder if I should switch to an RRE stealth with the stock exhaust tip. I do love the sound of the Greddy though.

 

I just downloaded decibel meter pro on my iphone 3GS. Tomorrow i'll record the readings

My exhaust is 3" megan dp, with 3"TP, 3" junb.l cbe. I also have GSC S2's