PCA SDR

Hi:

I was looking around to see what the exhaust noise limit is for Qualcomm. I can only find a reference to logging the noise levels but not anything on limits.

Is there a specified limit for this?

Regards,
Kevin

Hi , at the Monday june 19th Ax the figure of 92Db was mentioned at the drivers meeting as being a stadium limit. Cheers, Ralph

Yes the noise limit for the Q is 92 dB.

Greg

...and Greg should know, since his beast of a 928 regularly reaches that limit!

Right-O. It's time for some mufflers...

Regards,
Kevin

Greg Phillips wrote:Yes the noise limit for the Q is 92 dB.

That is what PCA uses, but the actual requirement from the stadium management is 93db, measured at 50' distance from the track, which is the spec for all SCCA events at the stadium. My understanding is that we have applied a conservative limit that is less than required by 1 db. SCCA warns people at 92, but does not require any action until 93db is exceeded.

TT

Why don't we use the SCCA ruling then?

I am the Sound Chair for the San Diego Region SCCA.

The stadium contract says something to the effect that all activity must be below 89db before 12pm, then limited to 93db thereafter. But measured at what distance? We are not told......sooooooooo the SCCA has sound meters at 50' at straight areas of the course (at least a 100' straightaway, with no reflective objects like barriers, bridges, Roach Coaches, or unnecessarily fat people). Sound logs are maintained for each passing vehicle and warnings are given throughout the day as needed. Apparently this is to satisfy any complaints that may arise due to loud cars, and provide proof of due diligence to stay under the sound levels.

In ACTUALITY, it provides a platform for smug unhappy people to point fingers, complain, and generally provide an Official Bad Time to the rest of the organization, who are usually good natured and relaxed and deserve no such treatment. This action is further repeated in meetings, on message boards, at my place of business, and haunts me in my dreams.

My Official SCCA Sound Chair Response to this thread?

"Make sure you have a muffler...if it is so annoyingly loud (completely subjective) that people take notice in a bad way, then please find a way to make it quieter or more pleasant next time".

This makes everyone happy, but MORE IMPORTANTLY maintains the wonderful, calm, happy demeanor that draws so many people into the PCA, especially SDR. Even though PCASDR does not usually record sound measurements or scream irately during the driver's meeting, I have found us to be doing a pretty darn good job and have heard of no major sound issues with the autocrosses and DE's at Qualcomm.

Keep up the good work, and try not to let "what the SCCA does" poison what a good, nay GREAT autocross and DE program that we have!!!

-James

JamesWilson wrote:The stadium contract says something to the effect that all activity must be below 89db before 12pm, then limited to 93db thereafter. But measured at what distance? We are not told...

That is very interesting, as the distance at which sound is measured from a source, as well as atmosheric and geographic conditions, not to mention the accuracy/calibration of the meter used and how it weights the A, B and C sound ranges, can make a HUGE difference in readings. 1-4 decibels is a fairly insignificant range in comparison to these variables. I have heard that doubling the distance to 100' would result in a 6db reduction of measured noise levels alone. If the stadium has not designated anything specific, our sound measurements and enforcement are pretty meaningless.

I do know that the local SCCA clubs schedule their run groups at Qualcomm with stock cars out first in the early morning, and the modified cars later, supposedly to conform to the two different levels mentioned in James' post (modified cars being assumed to be louder.) When I ran the SCCA National Tour event in my FF in 2002, the C-Modified group was scheduled to run in the first heat by the National staff, but was then changed to the last group after consultation with the local clubs on the day of the event, purportedly due to noise considerations.

TT