decibel level for AX, Whats too much? Options

[Rough_Rider]

So i popped off the banana muffler & fired her up on the driveway, ferking heck thats loud. I reckon 105-110db.

Presumably thats how loud it'd stay with megaphones or some straight pipe!! Dang. Sound good though (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) just need earplugs.


Question is how loud is too loud for AX / track venues. circa 95db?? Didn't see anything specific in PCA or SCCA rules.

[boxstr]

Trev I know PIR, has a set level for noise emmisson from race cars. You might check there website and see if posted there. JP might be able to help. He may be sniffing paint fumes in the garage still.
CCLINMIDASIZEIT

[ArtechnikA]

typically, it's 92dB-A. the 'A' scale is critically important.

it also matters how it's measured. IIRC, in San Diego Region, it was 30' from the car and perpendicular to its axis of travel. ( do not know if it was always the same side, the side away from a side-discharge exhaust, or on the same side. for a rear-discharge exhaust, it's a wash, i guess... )

Laguna Seca uses 92 dB-A for all but its few 'unlimited' weekends.

[Dave_Darling]

Typically, it's "whatever the site allows". Each site has its own policies, and the clubs are pretty much there completely at the mercy of whomever owns the site.

PCA Zone 7's rules, I believe, only say "No open exhaust". But most sites have their own limits. Most of those involve the number of complaints they get, though, not a specific decibel reading.

Laguna Seca has a number of different levels that are allowed on different days. I believe there are even some 89 dBA days, and there are 95, 98, and possibly 102 or 103 dBA days. And for just a few glorious weekends per year, there are no sound limits...

--DD

[lapuwali]

It also depends on the venue. I've been to events with completely unmuffled full racing cars, but they're usually held in places out in the sticks. The very best venue I've known about was literally next to a busy working airport, so sound level was a complete non-issue. IMHO, anything over 98dB is getting unsocial, and some full racing clubs limit you to 103dB regardless of venue.

Laguna's 92dB limit is very picky, as they have asshole neighbors with money and no sense (buy land and build a house within earshot of a racetrack THEN complain about the noise). They do a pretty serious job of enforcing it.

[Toast]

I would assume that 180 dBA would be the max. (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)






(similar to a rocket launch) (IMG:http://www.914world.com/bbs2/html/emoticons/burnout.gif)

[Rough_Rider]

fyi just pinged the PIR (Portland) folks here's their response...

103 measured 50 feet from trackside for most events. Drags after 10 p.m. and Monday events are 90 db...the permanent monitor is almost at the 1/8th mile marker on the drag strip, on the west end of the 2nd grandstand. Clubs during race events usually also measure on the back straight near Turn 8.


Hmmm open mufflers or a shorty straight through muffler might not be that far from 103db... (IMG:http://www.914world.com/bbs2/html/emoticons/idea.gif)

[Joe Ricard]

Down here in the sticks there aren't any sound limits. there was a C prepared Camaro sitting next to me in grid I couldn't even hear my car running let alone think straight. He was just idleing.
the Raby powered E-mod car has a megaphone on it and it is LOUD on the straight sections cranking over 7K rpm.

[Andyrew]

See.. I think I have a problem here... My car has a good rumble, and is a good deal loud, but mellow at the same time... Thats daily driving style.. You floor the sucker, it feels good, kicks open the secondary's.. and well.. All hell breaks loose, and it sounds like open headers from the back, My parents can hear me from a 1/2 mile away in the city...

I need to check the DB level.. but I think I have a problem here.. lol

[J P Stein]

At both SCCA & PCA AXs at PIR, there are cars that can make your ears bleed .....a BP early Vette(fast mo fo) and most assholes with RX7s (possibly the most obnoxious sound on earth)....they seem to think they can make up for being slow with a shit load of noise.
Anyhew, no official type has ever said anything about it.

I've been laying off the paint for a bit in the faint hope that some neurological pathways will repair themselves......thus far, no joy. (IMG:http://www.914world.com/bbs2/html/emoticons/wacko.gif)

[Joe Bob]

88-92 are the most normal limits. Each site will let ya know. As Herzog mentioned, they use the dbA scale....that's important as some morons don't know that the meters most always default to "C" scale when turned on and off...which depending on the "tone" of your car can give false limits.

I was black flagged once and I asked to see the meter...yup in C mode. I pointed it out and then showed them their own rules...they still were pissy...but consider the source it was a PCA event.

San Diego @ Jack Murphy was/is 92 with a rumor to 90 soon, Laguna last I heard was 88.....the tracks that are in the boonies usually don't have limits.

Be advised...MOST stock motors lose bottom end w/o a muffler providing back pressure. You MIGHT gain some on the top end....but I like the low end grunt.

Manfred runs better with a 2-1 Bursch than with the zoomies....same with Frank and my 3.6 powered 911.

YMMV

[ArtechnikA]

QUOTE (mikez @ Mar 10 2005, 05:44 PM)

Be advised...MOST stock motors lose bottom end w/o a muffler providing back pressure.

that's true. the better breathing will also want to make the car run leaner which will increase its tendency to ping -- which you won't be able to hear any more...

i've heard that "about" 5 clicks on the 'part throttle' MFI adjustment is a good baseline for enrichening an E, and AT LEAST ONCE i will run the car with megaphones at Watkins Glen, just for nostalgia and because i can... (it's 'mostly' stock :-) ...)