How LOUD are you. A poll!

[spookypt]

Hi all, a question. Nothing to do with my beautiful racer BUT

if 93 - 95 Dba is the generic standard for exhaust noise... How loud is your "street" exhaust while driven normally

[spookypt]

To begin the responses.... mine when switched off and not actually running is as quiet as a mouse... Dont suppose that can be classed as driven normally but its about as normal as it's ever gonna get!

[Shelby400]

Not sure what mine registers on the loud meter but its definately way past the pain threshold.

[dbn04]

mine passed inspection with flying colours (i believe the engineer said thats the quitest cobra i have heard)then on the day it was redgistered the mufflers fell off , its good for around town when you are just cruising but boot it and the brainns start to rattle ,just love it

[Aussie Mike]

First thing in the morning shortly after I wake up is when I'm loudest. Fortunately the doona muffles a lot of the sound (and the smell) but quite often I'm loud enough to wake up my daughter at the other end of the house.

I've got a digital noise meter, I'll have to set it up the night before and get an official reading.

[BOURRET]

Mine is sufficiently noisy to be refused at some tracks in England.
I have a dBmeter but I did not used it yet.

[REPTYL]

When I had the side pipes running I did a little test down the south eastern freeway.

Held the sound meter at my right ear while doing 100 k/ph.

109db at my ear!!!!!!

Let’s just say I started wearing earplugs while driving the Cobra long distances.

The exhaust now exits out the back of the car and I must say it's much nicer that way.

When I had the car engineered for the first time it blew 102db at the tip.
It had to be 92db 4 inches from the tip at 45 degrees at 2/3 max revs.
To get it to that I ran duel inch and five eighths exhaust with 2 commodore mufflers, four resonators and two and a half metres of chook wire jammed up the tail pipes.
From memory it blew 98db with out the chook wire. (max revs dropped to 4 grand when the wire was added).

What ever it takes, right.

[Aussie Mike]

Part of you problem Jason was that the measurement should have been taken a 525mm from the tip. 4" is way too close.

Cheers

[REPTYL]

OK so 4" was an estimate. It was 1998 for god sake!
I have trouble remembering what I had for breaky this morning, let alone engineering requirments for noise testing pre 2000.

[400TT]

Well your guess is as good as mine...

On the GT40 by time I fit headers, I've got room for an 11" muffler and an inch of pipe either side. No idea how I'm going to fit my large ricer exhaust tips in yet.

So I've got an 11" muffler &a few inches of pipe after the collectors...I reckon it's going to be real quiet.

Seriously though, my brother drives one of the quietest cars in the club...silent, but deadly. Hairdryers make for very effective mufflers.

[OLSCHL]

Hey Jas i saw you while back on your way up to Calder Park (i think) on Citylink (i was heading in the other direction) Could hear you coming from a mile away!! I reckon it was 109db at my ear on the other side of the road (over the other side of the barrier!!

[Cameron Parsons]

Ahh the wonders of the Roadster configuration. I think I have about 4 mtrs of exhaust to play with. Still run cats and mufflers. At highway speeds, it's a quiet burble. Give it a boot full and those 8 TB's start to protest

However, I got to drive Garretts beast at Winton... it was actually painful. But there is truth to the saying 'it's a fine line between pleasure and pain"

Cameron



2 X 2.5 Inch

[Kanga]

Spookypt

What type of side pipes are you running, mine are spiral only with cats, they are too loud and give me a headache after awhile. I have been thinking about turning them back under the car and out the back, however there is no ground clearance on a classic revival, something I wish Ian had worked on to improve. I like the look of side pipes but not the noise. I would be interested to know if anyone is running 'quite' side pipes and how have they achieved this.


steve

[Plums]

Unfortunately, (and I don't know because my car isn't even built yet) I think that the sidepipes will be loud because they are right next to you. My Ute is very quiet, but I think if the pipes were coming out next to me I may have a different opinion.

Kanga, do you have hotdog style mufflers, or perforated tube and glass inside your sidepipes? There are many different types of these "hotdogs" (perforated tube, louvered, different sound deadening material etc.) that may do the trick.

[Rebel1]

I'm with Cameron, side pipes are a pain on the road.

Apart from the noise, I have a genuine fear. That is that some young kid, my grandson maybe, runs up to welcome me or to look at the car and uses the pipe as a step up.

Don't get me wrong...I'm not critical of those using them...but....I really have this fear and would never forgive myself if that ever happened.

So...it's pretend ones for me...nice and quiet, and saves me hanging around until the pipes have cooled to leave the car.

[Cobra.au]

At the moment mine will set of car alarms easily while driving along the suburban street but my new pipes have 2" primaries and 3" cat into straight through 3" perf pipe I will have to get back to you on those.

[Don]

Just for comparison purposes, the standards used by Connecticut DMV during the inspection for registration. The DMV Inspectors are using a dB meter:


"CT DMV Section 14-80a-4a , Allowable Noise Levels since Jan 1, 1979. The maximum dB for a stationary test is 72 dB for soft site( grass ) and 74 dB for hard site ( pavement ). Section 14-80a-9a mentions the distance for measuring the dB. The baseline is 48 feet or more but less than 58ft. An adjustment to the dB reading is made up or down for readings either closer or farther away than the baseline range. The max reading is 81 dB for a hard site, highway operation above 35MPH, using the 48 to 58 ft baseline for measuring. "
_

[Kanga]

Plums,

there is no hotdogs in them, there is a central pipe and a spiral around this, I think that a lot or hot rods use this type of system.

steve

[Philm]

I run a 2 1/2 inch perforated tube wrapped in fiberglass in my 4 inch side pipes. This was fine when short shifting arround town and cruising at low revs on the freeway.

The new engine is a different story, the same pipes are now extremely loud, I too need to find a way to quite them down.

The noise tests are a joke, i had a simple under the car exhaust that was quite in the first place, but not quite enough. I stuffed a few stainless scourers up the pipe and that go me thru. the car was just running.

Phil

[OZVENOM]

speak up ay!!