Sound Meter Testing / Logging

[PaulB]

Current pipe 108-110
3inch borla 100-103
5ft long dual muffler in my garage???


I can understand the reasoning for not allowing the 90 degree left/right.
What about turn up's like those used at LS that go straight up?

When will we know what the number is?
I can make the car as quiet as needed ---which is fine but we need to know when or where we can "officially test" and what the official number is???
should I have added the 45lbs of mufflers for the east track or for the upcoming west-
I guess I can also turn the RPM down and run in C...

Don't forget about the air intake noise-

[J Richard]

The DB levels are only half of the equation, the weighting of the sound curve is a huge variable, and will make a big difference in the "official" reading. You can get a big low frequency motor to pass much easier than a small high revving motor. Trying to do it on a dyno or in a shop is almost impossible they can give you a baseline, but the on the track sound level is what matters...

...and pauls car is too loud...even with the motor off....

[j0oftheworld]

At FIR East Paul was 112..
The Big Bore Viper and Blk Vette were both a close 108..

If you were @ FIR East last month and handed in a "logbook" check the inside of the front cover and you *may* have a reading.

None of the cars measured in the HPDE sessions were over 100 so obviously there's a gap to the race groups and some TT cars.

Remember to not get too worked up about this. Nothing's been set in stone and members are being made aware to solely aid in organizing this data collection.

..and no lifting when you pass by the metering zone!! ahaha

[wmckeenster]

with all due respect, I doubt many cars at all would even come close to pass at 90db....good luck to them trying to pull many successful race events off at AMP...

Geez, what a joke too being right next door to Luke!

[BigBadBlue96]

Originally Posted by wmckeenster

with all due respect, I doubt many cars at all would even come close to pass at 90db....good luck to them trying to pull many successful race events off at AMP...

Geez, what a joke too being right next door to Luke!

I'll take that bet!

My stock LS6 enginewith modified intake and exhaust was metered at 50 ft. at San Diego with lower temperatures and high humidity at 89 Db with the BMW, yes BMW, 1/2 tubes on the back of my Billy Boats.

Stock LS6 engine with only Billy Boat Bullets with 8" resonators = 93 Db
Stock LS6 engine with Kook headers and Billy Boats Bullets= 99 Db.
Stock LS6 engine with Kook headers and Billy Boats Bullets and BMW 6" tubes= 89Db.

[crazy_ugly_coyote]

So since I have a side exit exhaust on the drivers side would that help that much with the sound reading since I assume the reading will be done on the outside of the course.

[Dave "turtlespeed" Schutt]

since I haven't seen a scheduled date yet for AMP I'm not gonna start scrambling. I'm sure as a date is set and the closer we actually get to an actual event there will be more and more chances to pass whatever noise level the track wants. as it stands now it almost seems like they want showroom stock noise levels. maybe our tire screeching will piss off the neighbors if the engines don't. LOL.

[Tage]

Please stop quoting specific dB levels. It has NOT been announced what the limit will be yet.

Darrell, that's some good comparison data but the problem with your example is it looks like the majority of the effectiveness of those exhaust tips are due to them being pointed away (right or left) from the sound meter which will not be allowed.

Paul, I'm not sure if they will allow sound to be pointed up or down but my guess is no. I know I tried going straight up in San Diego and it made no noticable difference but it likely made the sound travel further for others not at the event to hear.

Jake, good question on the side exit exhausts. The point is not to get creative to fool the meter. The point is to keep the cars as quiet as possible to avoid the place getting shutdown a 2nd time once they re-open. If people still complain we can quickly show them that we met the sound requirements. If inspectors come onsite and see a bunch of 90 deg exhaust elbows and side exit exhausts on the opposite side of the meter, that just isn't going to fly.

Dave, good point on the fact that there's no need to scramble since there isn't a data set yet at AMP nor is there a projected date. Just trying to be prepared to avoid a mad rush. However, keep in mind that we will NOT do sound meter testing at PIR. So the only other opportunity to do testing would be at FIR East in Oct.

[treefrogaz]

Well let me know what we need to do we all have our passport books. See how loud the Subaru's are.

[Leland]

too bad there wasnt something else that could be done to deaden the noise...
landscaping, barrier material, wall material, banks... stuff to absorb the sound waves.