Event #11 Sound "Hall of Shame"

[benk]

Mike, on Vrooman's times (FS 123/23) we switched cars and numbers for the last two runs. At that point were you tying sound to the car or the numbers? Just wondering if Steve got my M3 into danger range or if those last two runs were on the challenger while i was driving? I expect the latter but just want to confirm.

[MikeKelly]

Mike, on Vrooman's times (FS 123/23) we switched cars and numbers for the last two runs. At that point were you tying sound to the car or the numbers? Just wondering if Steve got my M3 into danger range or if those last two runs were on the challenger while i was driving? I expect the latter but just want to confirm.

I noticed that and kept the sound numbers with the cars.

FS14 (car): 84.8, 76.0, 81.8, 80.0, no reading - unknown reason (I don't recall)

FSL14: 75.4, 76.9, 80.2, 81.1, 81.3

[flier129]

STM 92?

[MikeKelly]

Further examination of details relating to Eric Anderson's event #11 sound results:

Jim "literalist" Simmons ran his car without augers for the first time in recent memory, and expected to top 100db. He didn't miss it much, but he did miss it. I didn't get to discuss it at length with him, but I know I wasn't as hard in the throttle in front of sound as I wanted to be due to "too slick". I also made two runs without augers and expected to break 100db - I didn't make it either...


Lots of data for all three run groups on Jim Simmons car (charity runs), two run groups for Eric (same):

Jim Simmons car - 1st run group 97.4, 96.9, 96.6 - 2nd run group 95.4, 97.8, 97.5 - 3rd run group 98.4, 97.9, 99.7, 98.6, 99.8 / 89.9, 98.9, 97.5, 99.0, 97.8

Eric Anderson - 1st run group 95.1, 97.6, 96.4,96.7, 99.1, 96.6 - 2nd run group - 98.8, 95.7, 96.4, 97.8, 97.5

Mike Kelly - 3rd run group 96.6, 96.0, add SuperTrapps - 90.6, 91.8, 88.8

John Brown's car produced exactly the results he + I expected (all day) with SuperTrapp tests - 1st run group (7 fewer disks) 90.9, spin - 3rd run group (7 more disks) 93.3, 94.3, 91.7, 94.1, 94.6 / 93.4, 94.9, 92.8, 93.4, 93.5


Jim was low, I was low, Coatney was low, JB was right on the money, Eric Anderson is ~ 10db high.



Further details:

Eric Anderson event #2: 85.2, 87.0, 87.2, 87.4
Jim Simmons event #2: 88.3, 91.3, 93.8, 93.3 / 92.9, 93.2, 93.9

Eric Anderson event #8: 87.9, 89.4, 89.4, 89.3, 86.6
Jim Simmons event #8: 95.0, 92.4, 93.3, 92.8, 93.4


I'm telling you that something on Eric's car is broke, or something really weird went on with that particular venue and sound meter location that only affected one car (and maybe a kart), or that SuperTrapp addition set up a resonance in the exhaust system.



It's the best I can do with it...



P.S. - STM92: 87.5, 85.9, 87.7, 89.7, 89.4

[benk]

Mike, on Vrooman's times (FS 123/23) we switched cars and numbers for the last two runs. At that point were you tying sound to the car or the numbers? Just wondering if Steve got my M3 into danger range or if those last two runs were on the challenger while i was driving? I expect the latter but just want to confirm.

I noticed that and kept the sound numbers with the cars.

FS14 (car): 84.8, 76.0, 81.8, 80.0, no reading - unknown reason (I don't recall)

FSL14: 75.4, 76.9, 80.2, 81.1, 81.3

Thanks Mike. I'm surprised the m3 is that loud. But good to know.

Sent from my SM-G900V using Tapatalk

[MikeKelly]

Thanks for the check, but I run lots of national events and have never blown over a 94 and for the last few years have been in the 89-92 range, regardless of conditions. My silencer likely needs repacked, but I don't believe I'm anywhere close to 96. But I also don't run at Pelly, so it's no biggie.

I am purposefully aggressive with meter location - to the point where I occasionally have to throw out an event's sound results.

I am intentionally producing the highest fair, honest, and repeatable sound results you're likely to receive anywhere.


If you examine sound meter location at national events with a critical eye, you will find that most events are not doing this - many are using ineffective meter locations for whatever reason.

I can pretty much guarantee you are in no danger whatsoever of blowing the national limit - at any venue.

You're definitely likely to get shut down at Pelli - academic if you don't run at pelli.


Further examination:

Ted (KM86) event #2: 82.4, 85.0, 83.5, 83.7
Ted event #3: 85.1, 84.2, 84.7, 84.3
Ted event #6: 87.2, 86.3, 85.0, 87.1 (huge straight)
Ted event #8: 83.1, 85.9, 84.7, 84.7, 84.6

Ted event #11: 83.3, 82.8, broke
Scott (KM68) event #11: 94.7, 93.2, 95.7, 95.9, 96.0

[steverife]

FWIW, I once got a higher reading on my CRX with it corked up compared to the wide open Supertrapp.

edit: even though it was decidedly quieter in the car with the disks.

[eunos735]

The Supertrap quieted the car 6db At Huntsville 3 or so weeks ago.

There is a good chance I was the only "fast" car on the throttle as much or as long through that section and the Traction Control is loud.

Not saying it wasn't fair. Just a statement of fact that the way we measure sound with the SCCA is annoying.....but it is what it is and there really isnt a realistic way to fix it. There are far too many inconsistencies with the setup and with the actual meter operation

The most likley culprits were:
A) The fact that I was able to use more power for longer than anyone else through that section (it was pretty damn slick)
B) the TC isn't quiet
C) It was a cool overcast day. For NA cars....that doesn't change much. Fot a blower car....makes a HUGE difference.

[MikeKelly]

B) the TC isn't quiet

Credible - What percentage is the TC typically doing in the straight at pelli?


Also - Coatney's supercharged, but I'm pretty certain he's not running near the boost levels you are.

And it was nicer weather for the third run group (Coatney) - but Jim + Ariel's numbers went up (more traction I presume).


Just further thoughts / details...

[John Brown]

Oh my... the pit falls of power.

[MikeKelly]

Oh my... the pit falls of power.

Heh - at least no one's trying to look up our skirts, lol...

[eunos735]

Oh my... the pit falls of power.

What do you mean "power?" It's just a Miata.

[MikeKelly]

Here's an angle:

With your particular setup - would it be a complete PITA to reduce boost by xx% (going in), rather than relying on the "loud" TC to reduce rear wheel HP by xx% (on course)?

I presume that would require a pulley swap on the blower (only?)?

Would that throw your tune all out of wack?


Or an adjustable throttle stop, maybe?


Just for sound sensitive locations.

Just asking.

[eunos735]

Yea.....that would be a bit of a pain.

It's going to be pretty much impossible to get it any quieter without really corking it up.

The Supertrap even has Stainless Steel scrubble in it.

It's not a huge deal. I hadn't intended on running the car there once the limit had changed anyway.....I don't wanna be the one that pushes the property owner over the edge.

I am, however, looking for a codrive next year in something competitive.

[JohnSmith]

Can I get the sound readings for STR 87 and STR 187?