Laguna 90db Day... Odds?
 

Has anyone else run this combo at a quiet Laguna Seca day and passed sound? TSE/EFR6258, 3" exhaust (no cat) through Magnaflow 5x8x18. I'm worried I won't make it. Laguna measures sound about 50ft from the racing line, from my understanding.

It's all about the muffler. I've never run the Magnaflow one, but I can tell you that my car with the 2863, no cat, and just the FM 3" muffler passed 90db no problem.

--Ian

Probably OK with a muffler. Weather affects readings. When it's foggy, sounds carries better so more cars blowing the sound check. Adding a resonator in the midpipe pretty much guarantees you'll make sound but a good muffler might do it.
Center exit (straight back) louder than the OEM S bend routing.

Time for some Laguna mufflers
https://www.autotrader.com/wp-conten...2/260090-1.jpg

Sound checks here are generally in-field. Sometimes (one hillclimb I know) they are between circuit and nearby housing. If it is a fixed position, putting an angled tip on, pointing away from the test equipment, might help, people here do it. But better to just get the sound down and you can sleep easy.

I had a shop replace my muffler this morning (old one was shot) and it measured 85db from about 4ft back according to my phone, revving while on the lift.

The sound shack at Laguna is track right between turn 5 and 6, about 50ft off the racing line. Does anyone know if it's 90db at the shack, or do they do some math to be equivalent to 90db at the muffler? I have a db meter at work and could measure more accurately... Might make one of those laguna turn up pipes anyway to have just in case.

Replicating the Laguna testing is hard. First off, phone sound meters aren't calibrated properly and usually don't have the right weighting scale. Second, the topography of the ground around matters, the hills, the reflectiveness of the asphalt, etc. Finally it also varies -- when it's cold and wet the sound carries further and it registers higher. It's not uncommon to have cars fail in the morning and pass in the afternoon.

It's also possible to fail for intake noise, although that tends to be more of a Honda (or S54!) problem than a Miata one.

I think it's 90db at the shack.

--Ian

Well, I guess we'll see. It's "pretty quiet" subjectively. Fingers crossed, otherwise I suppose I'll just lift from 5-6

If it's "pretty quiet" you're probably OK. When you go out for the first session go carefully up the hill between 5 and 6 at the beginning. Watch the clock and when you get close to the end of the session go for a full throttle run -- that way if you get a meatball you haven't lost much time and know that you need to lift for the rest of the day.

--Ian

Noise under load at WOT is different to that at low/no load. Also, try not to have any bangs or pops on upshift (or downshift as far as that goes, we had someone in our group get pinged for that once). Obv not over there though!

If it is like here, they have so show you the piece of paper with your reading at the meter.

At Laguna you get the meatball flag, pit, then when you get to the starter he tells you what the meter reading was. Then he points you into the paddock through the hole in the wall and your session is done.

--Ian

Narrator: it did not pass sound. Somehow they picked up 96.5dB

An attempt to make a muffler out of some chicken wire and steel wool lowered it to 88db but also almost caught fire. So I coasted past the sound booth the rest of the day. Still managed a 1:46, which I guess is alright. I tried to do a flying lap on my last session of the day but they brought out the checkered halfway through :(

Laguna is tough, I know people who have blown sound in stock GT3's.

Having a collection of 90 degree bends and turn downs help. It seem like a moving target that you gotta keep on top of to keep em happy.

You can thank the home owners who moved in next to a race track then complained about the noise for the excessive restrictions.

That sucks. I hate the new trend of throwing the checker in T7, halfway through the lap -- it screws up your ability to do a proper cooldown lap. I really wish they'd just throw it 45 seconds earlier at start/finish like they used to. Same cars-off-track time, but people who need more than 3 corners to cool the brakes can actually accomplish it.

96 db is surprisingly loud for a turbo Miata, mine is around 88. Are you planning on coming back, or was this a one-off thing?

--Ian

Not sure if I'll head back that way any time soon. It's a long haul from Orange County - towing even at 65mph kind of makes rapid progress difficult.
I also didn't believe 96db. It's pretty quiet by my standards, but lots of humidity (marine layer was still hanging around) and traffic might have contributed.

I'm toying with the idea of selling the car and getting something I can leave pretty stock and reliably drive to the track and back (cayman? m2?). Maybe I'll head back then.

I know its too late, but I have the same turbo kit, running the same exhaust/muffler on my car. I also clocked in at 96.5db. keeping to the left after t5 seems to just barely squeeze me by. I think a slip-on 90* is enough to pass sound there.