Question about noise limits at Palmer

[AVI8_636]

Hi, been a while (about 4 years) since I've been on track and I had a question about Palmer. I'm planning on signing up for an upcoming day but I have a modified (Actually built by a member here I believe back in the day) DRZ400SM and it currently runs an RS2 exhaust on it. How does the noise restriction work on track? The bike has been on track at NHMS numerous times without issue. I don't have any stock exhaust parts for it since I bought it in it's current state. I was looking at noise reduction inserts just incase but they haven't been in stock for some reason for the past few months on any websites or stores.

[Paul_E_D]

If it's a wide open pipe, you will need an insert.

[sdog30]

They are super strict there. They test on the back side were it's uphill and impossible not to be on the throttle on a small bike and radio it in.

I was getting yelled at all day on my yz450 (which had a graves exhaust) and then on my kx450f which had a stock exhaust.

[AVI8_636]

Damn, that's disappointing to hear. I don't understand how they expect a track to operate without noise...

I've tested it with a regular phone app and it didn't come near the 95 that their website states (I tested it 6ft away at a high RPM).

[Jim]

and then on my kx450f which had a stock exhaust.

this cracks me up. a stock exhaust is still too loud for a race track

[Paul_E_D]

this cracks me up. a stock exhaust is still too loud for a race track

Have you heard a stock MX bike lately? They are too loud. I'm trying to find a noise reducer for my KTM.

[aldend123]

Ya I don't think some stock-trim MX bikes will pass some sound checks at local races either. They're bizarrely loud.

I don't understand how they expect a track to operate without noise...

I doubt it's the track driving the expectation.

[sdog30]

The noise meter is to appease the neighbors who protest the track being there. Funny because I think I saw at least two burned down houses on the way to the track from the pike. I think I heard that they test it in that area of the track because that's the side the neighbors are on.

[sdog30]

The stock exhaust comment was more in reference to some aftermarket exhausts I've heard.

You guys remember the flat track set up that Shane ran on his Honda that JC had to go buy and put on his bike? Or any motard Sergio has owned with a yoshi on it?

[sdog30]

Damn, that's disappointing to hear. I don't understand how they expect a track to operate without noise...

I've tested it with a regular phone app and it didn't come near the 95 that their website states (I tested it 6ft away at a high RPM).

Maybe your bike will be fine. Drz is meant to have an inspection sticker on it, so is probably quieter. I was hammering mine pretty good and going back and forth all day with Dave Gelaher on his motard, too so might have been the combination of two motards together.

They always seemed to call my number though. Maybe the 666 had something to do with it? It was pretty frustrating though. We both vowed not to return with a motard. I'm planning on bringing my street triple in August.

[AVI8_636]

Thanks for the info guys. I can't seem to find inserts anywhere. They're sold out at all the online retailers for some reason. The palmer track website says 95db is the limit, I ran numerous different apps and they all registered under 90 while I held the throttle at a high rev. Still not sure I want to risk getting kicked out and losing out on all that cash for a track day...

[sdog30]

You should just go. I'm sure you'll be fine. They test it from the side of the track, so it's at a distance. I'll also specify, I didn't get kicked out. I ran the whole day. They just spoke to me three or four times throughout the day.

I'm sure your bike is quieter than mine. I was also riding in the advanced group ringing my bike out, so not sure what your pace is.

If I was willing to dog it through that one spot, they probably wouldn't have said anything to me. You should go. That track is very fun. Especially on a motard. The straight was a little long for it, but everywhere else is fine. The downhill, sweeping left in the back section is crazy fun on a motard too. You can carry so much speed.

[nhbubba]

I bought an insert for my SV650 before I ran there last time. Although the receipt I have says it is for an RS3 system. If you think it would fit I can dig it out and lend it to you.
FWIW I started the day with the insert in but removed it by the end of the day.
I was also running a WR450F supermoto with a stock exhaust that day and wasn't bothered. It was a wet day that dried out. Maybe I just got lucky and they only measured earlier in the day when we were all taking it easy.
I felt having the insert with me in my toolbox was a nicety. I'd have run without it.

[sdog30]

When I was in Florida at Jennings, they had a very strict noise level that they enforced in a similar way. My buddy I was with got flagged a couple times, so we took a piece of aluminum and attached it to the end of the muffler with hose clamps. It diverts the sound. He ran the rest of the weekend like that with no complaints. I think someone used to manufacture them and sell something similar at Laguna Seca.

[keeena]

You could get a generic insert like THIS; you typically wedge it into the inlet side of the exhaust can.

[sdog30]

Definitely don't shove a bunch of steel wool in... it will blow out within two turns. Lol

[sdog30]

This was our attempt at a homemade baffle. Looks like we did a little more than hose clamps.

[Paul_E_D]

If you measured out that low, I would go. In a weird coincidence, I just got an email that my Fastway billet endcap/sparkarrestor/dblimiter just shipped. It was on backorder for a month from motosport.com. It was stupidly expensive, but looks nice.

[AVI8_636]

This was our attempt at a homemade baffle. Looks like we did a little more than hose clamps.

Holy crap that's awesome and hilarious!

If you measured out that low, I would go. In a weird coincidence, I just got an email that my Fastway billet endcap/sparkarrestor/dblimiter just shipped. It was on backorder for a month from motosport.com. It was stupidly expensive, but looks nice.

Yeah it was measured with just a free phone app, so idk how accurate it is. I talked to a couple of online vendors on the phone this morning and they said basically everyone stopped making parts because of the rona so stock has been very limited.

[Paul_E_D]

Worst case, rig up a sound deflector like the one pictured. It will get you through.

[sdog30]

Seriously, just go and don't worry about it. You'll be fine. You'll have a great time. Those phone apps are pretty good.

[number9]

Damn, that's disappointing to hear. I don't understand how they expect a track to operate without noise...

I've tested it with a regular phone app and it didn't come near the 95 that their website states (I tested it 6ft away at a high RPM).

I am not an audio engineer, but: isn't the dB scale logarithmic? For every 3dB the sound energy doubles.

E.g. 93dB is twice as loud as 90dB, and 96dB is twice as loud as 93dB... so in other words, the 95dB limit is almost 4x as loud as 90dB.

You should be fine?

[sdog30]

I am not an audio engineer, but: isn't the dB scale logarithmic? For every 3dB the sound energy doubles.

E.g. 93dB is twice as loud as 90dB, and 96dB is twice as loud as 93dB... so in other words, the 95dB limit is almost 4x as loud 90dB.

You should be fine?

Is that Australian math?

[jasnmar]

Yes, a 3dB drop is represents 1/2 of the power as measured in sound pressure.

[number9]

Is that Australian math?

Yeah. Did you forget to turn your monitor upside down?