I keep reading how you FD guys say you're cars are loud with a full exhaust ect.. does anyone have readings from a db meter? I want to see how loud it is compared to a full exhaust NA FC.

I did a search but everything I found was like this..
"on a scale of 1-10 my car is a 4"

 

On a scale of 1-10 mine would be an 8. Straight Exhaust on stock turbos. It will be 10 once I get my Single turbo and have the wastegate open to the atmosphere. But yea, FD's with straight exhaust are damn loud.

 

Yeah but I'm looking for real numbers from a db meter.

from what I've experienced with my car and the scale you just used, my car should be at like 15

 

Yea I've been meaning to dB meter my exhaust, buy I HIGHLY doubt that your car is 50% louder than a FD with straight exhaust. I don't know of any car louder than mine where I live except this one Integra Type R that is runny just headers only.

 

Turbos absorb some of the sound, so a NA FC with full exhaust will always be louder. Not by much, but definitely louder.

Based upon some sound tests we've done with bikes (and remembering a friend's bridgeported RX-2 that he autocrossed way back when), I'd estimate a healthy NA ported FC with straight exhaust is probably around the 115 db mark at full song.

 

he wants to know an FD db reading not FC......he has an FC and wants to know how loud it is compared to an FD. Maybe the FD's are too loud, cause no one seems to listen sometimes. I'm not trying to be mean so please don't take it that way, just saying sometimes people miss or misread things. Read carefully is all I'm saying. Unless I misunderstood YOU.

 

Well, I guess I figured he could guesstimate from that on where a straight exhaust FD will be, since turbos will absorb some of the sound. Not really too concerned with exactly how much louder one car really from the next...

 

"Cossie" posted in a thread a while back about not meeting the track noise limit of 92db (until he did a little exhaust mod).

 

At school I was using a fairly accurate decibel meter good to well over 150 on a project, but didn’t even think about testing the FD.

Maybe I can borrow it from the professor, and test out the RB duel tip once Jason gets it to me.

Does anybody know the estimated arrival dates of those CBs purchased through the GB?

 

92 dB noise limit? S#!t, I'm screwed I'm sure.

 

hehe, i think mines to loud.

especially under wot.

At wot, you can honestly hear me from a mile away.

 

Hurrrm.. Try a BP N/A motor... it's the voice of god!

-Markus

 

I have a couple of results.

Straight thru exhaust with a rice style fart can (Top Speed Cat back) measured 105 DB at Idle at a 45 degree angle from 2 feet away.

Switched to a Racing Beat cat back, MP, and DP. and measured 96DB at idle, at 45 degree angle from 2 feet away.

I will be adding a the RX 7 store resonated midpipe next week, and will take a couple more readings. I still don't think I will fall under the legal noise requirements for california, but it will be quiet enough to detract some attention.

 

Thanks for the info guys, I wish I could remember my physics stuff.. from what I remember increasing a db is like 3x the volume of the previous measurement.

My car would run 95-100 db at idle and just under 120 maxing out 2nd gear from about 15-20 feet away.


http://zeffy.novus-logic.com/media/fc%20loud.wmv

 

First of all, there is a big difference between measuring unweighted decibels and a-weighted decibels. For those of you measuring in the 90-100 dB range at IDLE, that is measuring unweighted (or c-weighted, which is pretty close for most purposes). Any noise standard at a race track or for state noise control purposes, will be a-weighted.

Also, distance and angle to the tailpipe will be required for any measurement to be compared with another (as Jesuscookies measured). For example, Laguna Seca has a 92 dBA noise limit at I believe 50 feet. Now that translates to 110-116 dBA at 3 feet from the exhaust opening.

I would measure my exhaust for you but I still have a stock cat, so not much of a useful comparison for you.

 

just cought me at a bored moment so i went and checked mine, i got completely catless exhaust (apexi n1 muffler) stock twins....

at idle on the c weighting mode it read 108 db

this is 700 rpms.

yeah, its loud

 

I didn't check the legal requirements for measuring a cars noise level, go ahead and search if you like. 3dB is double the noise power (twice as loud, I suppose). You can just notice a 3dB change (which is why the scale ended up that way - done by the telephone engineers way back in the day). My Radio Shack digital sound level meter does both "A" and "C" weighting, but unfortunately, my car is off sleeping in the garage till next April. If you do test a car don't get too close. Check the regs. and you'll see the distance is around 20 ft. Remember your inverse square laws? The sound level drops very quickly with distance. BTW 108 dB (c or a) at a reasonable distance, will cause permanant hearing loss. I presume that was right close to the pipe?

My ears don't bleed so the car is quiet ;-).

 

that measurement was at 3 feet away from the tip and at a 45 degree angle, i measured this way because its what i thought was the correct distance for mesurement coiensiding with government standards

 

Every state is going to be different. I am not sure of the exact techinque used here in the **** Smog Capital. (AKA California) what I believe they do is they measure the car at 3500 to 4500RPM from 2 feet away at a 45 degree angle. They do not just measure level at idle.

 

lol, ill measure my car at 4k tomorrow from 2 feet, i just hope my db meter goes up that high

 

when your passenger actually looses a bit of hearing because you are driving spiritedly and with yoru windows down. (this actually happened when i rode in my brothers old fd when he had a 3 inch dp and 4 inch mp/catback straight thru type)!