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3 Generations on a MkIII
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1,415 Posts
Discussion Starter · #1 ·
So far I have a bone stock 5.0 and in the process of tear-down. Stock intake and exhaust. :( I was looking at going with 3.55s and found a thread with this link http://www.corral.net/tech/gearcalc.html BUT I have never heard an FFR in the flesh. I know everyone has a differnt idea of what loud is. But at what RPM on a 302 does the symphony become a cacophony of devastation?
 

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FFCobra Craftsman
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1,767 Posts
I can tell you I heard a stock 302 with 4x4 headers and it was about half as loud as my 347 with Dart heads and the same headers. The stock car sounded mellow to my ears. The difference3 in noise is surprising.
Steve
 

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3 Generations on a MkIII
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1,415 Posts
Discussion Starter · #4 ·
I agree that setting off car alarms would be "great fun". I want loud. But a 300 mile road trip sounds good too. Thanks "Mancunian" your responce was the best Candidate. ;)

Anyone ever put a Db meter on one of these things?
 

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Former Roadster Owner
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1,861 Posts
Pb foot,

Its like you said, it depends on what your experience is and what you're use to. I had a 440ci Dodge Coronet R/T that was much more thunderous than my 347 powered Roadster. By thunderous I mean ground shaking--feel it in your chest--and causes you to wonder if your heart will change rhythm. The Roadster still has a commanding presence, but its loudness is just that and nothing more. This loudness occurs in the upper rpms, which is clearly a characteristic of the Glass-Pack side exhaust. I'd say by 3500-4000 rpm I'd consider the car really loud. Under 2500rpm I feel the car is actually fairly quiet.
I also owned a 03 Cobra with an off-road H pipe and Bassani exhaust. That car was much louder at high rpm than my roadster, but of course it idled like a kitten. -Dan
 

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Senior Member
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3,798 Posts
No Db meeter, but my son got a thril the other day when we set off several alarms in a store parking lot and that was when going less than 10 mph!
 

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3 Generations on a MkIII
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1,415 Posts
Discussion Starter · #7 ·
Thanks FordManDan. I will go with the 3.55s now. I enjoyed your description of the 440ci Dodge. I did find a post where a DB meter was used. His was in the "Threshold of pain". I have made the choice to bulid and drive a car that can set off alarms. Others on the side walk.... I don't want little kids crying. Drooling yes. Threshold of pain...not so much.
 

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Charter Member
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When a cop comes by I usually upshift or throw it in neutral and coast. If "Brutus" is running above 2000, it starts getting really frakken loud. Earplugs are mandatory. This is why I am a proponant of the 3:08 gears. I can cruise without shattering everyones earbone.
 

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3 Generations on a MkIII
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1,415 Posts
Discussion Starter · #9 ·
Please tell me about "Brutus". I'll pay you tomorrow for stats today :D
 

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Premium Member
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9,698 Posts
Check out my dyno operator, this was at 6100 RPM. I was standing about 20 ft away, when I took the photo and I could feel the pressure on my chest.
 

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Premium Member
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6,142 Posts
Any long trip and its ear plugs for me. Not so much sound but the wind blows straight thru my head.

0-3000 RPM is mild. So highway speed is ok noise wise.
 

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Senior Charter Member
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2,397 Posts
30 min's at highway speed and my ears ring for a about an hour. ear plugs for me any time i get in the car now.
 

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FFCobra Fanatic
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12,975 Posts
With the stock motor at highway speeds the exsaust is not that loud at cruise. The noise happens when you put the power to it. At 65 mph wind noise will be a concern. Mine starts to change note around 3000rpms and up. Course loud is in the ear of the beholder.
 

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Senior Charter Member
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Heck, I've got cats with stock headers and I set off car alarms!
 

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Master "Gear Head"
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434 Posts
Originally posted by Pb Foot:
Anyone ever put a Db meter on one of these things?
Yep, a few people have (including myself). Check here for some readings I recently took, in an Excel spreadsheet. The numbers are in a 3 car garage with the doors open, so the readings will be somewhat high compared to real world use but not by much. When I had my 408 with 4 into 4's and brand new sidepipes, I took the car outside and took some sound measurements. I got 99 dB's at idle 6' away and back even with the rear tire! Compare that to the data in the spreadsheet and the indoor readings aren't up to far from expected outside readings for my current motor (maybe 2-3 dB's).

There is also a thread here on the subject of exhaust loudness. This thread also has sound files to go along with the SPL data. Also check in here for another thread on some upcoming dyno tests of different exhaust setups (with SPL measurements to be taken as well).

Be aware that the sound you get when the glasspacks are new will be different from when the glass packing blows out with use. They get much louder when they get some miles on them.

Note: All my SPL readings are using C weighted measurements. "A" weighted measurements are much lower (in the order of 10-15 dB's) and is really geared for measurement of the human voice and that sort of thing. C is the right "weighting" to use I believe.

[ December 20, 2006, 01:05 PM: Message edited by: Got-V8? ]
 

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1st RFM/FFR Legacy Winner
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Huugh? What?
 

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Charter Member
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Stats on "Brutus". Just a 5.0 with Twisted Wedge heads, E-cam, Programable Computer, "Ported and Flowed" 65mm throttle body, 70mm mass air, Aluminum flywheel, power pulleys, 93 Cobra Intake, J-pipes. About 350hp. Fast little small block. The pipes are 7 years old so I don't know how much glass is still inside. LOUD! Oh, 82 Db at idle. Off the meter at speed.
 
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