Jump to content
Bill Strong

Laguna Seca - Quiet!!! - How to make your race car quiet document

Recommended Posts

I am up working late. Decided to tackle something that caused us quite a number of issues at last year's WeatherTech Raceway Laguna Seca event. I will be including this document in the supps for the December event. I would request some feedback from racers. I only have my own Laguna Seca experiences and would welcome yours.
Now, remember, in the past, it was 3 strikes and you were done for the day. Now, it is 3-strikes and you are done for the event. So if you get three hits on Fridays test day, you are done and asked to go home. There is no testing. done.
Mike Chisek and Mike Morrison and I have discussed using the morning session on Friday to use the front straight to test your sound levels using ChampCar sound meters at certain levels. But there were a few people that did not want that precious track time taken away from them. We are still in discussion about this issue. 
Please give me feedback on this document.

 


 

Screen Shot 2019-03-15 at 9.20.57 AM.png

 

 

 

 

SoundLimits.pdf

Edited by Bill Strong
document and image edited with additional content and edited for terminology.

Share this post


Link to post
Share on other sites

@Bill Strong Thanks for the info! Do you have any info about tubing size? For instance, if I have 2.5" tubing and a 2.5" x 30" cherry bomb, would it be quieter if I went to 2" tubing with 2" x 30" cherry bomb? And how much quieter? (obviously would need more than that for Laguna, but trying to gain insight)

Share this post


Link to post
Share on other sites

What did I say about flow through mufflers? Cherry Bombs won't pass. They are too loud. Now maybe 90" of cherry bombs may, combined with a Chery Bomb Turbo muffler...

 

  • Like 1

Share this post


Link to post
Share on other sites
8 minutes ago, enginerd said:

(obviously would need more than that for Laguna, but trying to gain insight)

 

3 minutes ago, Bill Strong said:

What did I say about flow through mufflers? Cherry Bombs won't pass. They are too loud. Now maybe 90" of cherry bombs may, combined with a Chery Bomb Turbo muffler...

 

Fine, how much quieter is a walker muffler with 2" inlet compared to walker with 2.5" inlet

Edited by enginerd
  • Like 1

Share this post


Link to post
Share on other sites

the other issue is open element air filters... 

the valve / intake roar is probably what got the 46 Uncommon Friends Datsun 280Z kicked out on lap 4 of the Saturday race.
A quiet STOCK baffled stock air box should be good.

 

  • Like 1

Share this post


Link to post
Share on other sites

My go to book is the standard exhaust book for like 100-years. You read it and you are blown away with the science that was done on the exhaust system in the early 1900s. Then you ask yourself why you are reading this because none of it applies to you and your 900hp car with 4" exhaust.

But look past the numbers and look at the engineering and science and you will see that so many "new exhaust muffler tech" is not really new, just forgotten. Today's new trend was done 70 years ago...
 

It's late - my book is in my bedroom with my wife sleeping. She will kill me if I go in there and rummage through stuff to try and find it.

https://www.amazon.com/Scientific-Exhaust-Systems-Engineering-Performance/dp/0837603099

 

 

Share this post


Link to post
Share on other sites
8 minutes ago, enginerd said:

 

 

Fine, how much quieter is a walker muffler with 2" inlet compared to walker with 2.5" inlet

 

 

Good. stop using big words.

 

I don't know. But the sound is quieted by the expansion from the pipe to the open chamber of the muffler. So you would think that going from 2" to 8" would be quieter than 2.5" to 8".
But I would need to test it. and all my cars are not working, well except for the Opel. 

  • Like 1

Share this post


Link to post
Share on other sites

If you have a certain RPM you're trying to attenuate, Helmholtz resonators are pretty interesting. https://grassrootsmotorsports.com/forum/grm/problem-exhaust-drone-solution-side-branch-aka-14-wave-resonator-or-helmholtz-resonator/129212/page1/

 

This is more for tuning street car sound, for a race car to pass testing I'd say  you'd want to use more of a sledgehammer than a scalpel like this.

 

You don't want to be anywhere near the limit on track, because even the weather can cause the SPL reading to change a lot.

Share this post


Link to post
Share on other sites

How about we keep the offensive, borderline racist words like "ricer" off our official documents, and leave them to the conversations between chew spittin, busche lite swillin, good ol boys.

 

See also, "that's our word, you can't use it"

  • Like 3

Share this post


Link to post
Share on other sites
7 hours ago, enginerd said:

@Bill Strong Thanks for the info! Do you have any info about tubing size? For instance, if I have 2.5" tubing and a 2.5" x 30" cherry bomb, would it be quieter if I went to 2" tubing with 2" x 30" cherry bomb? And how much quieter? (obviously would need more than that for Laguna, but trying to gain insight)

 

I can tell you that I went from 2.5 to 3 inch, same brand muffler cherry bomb, same routing, etc and it got much louder

  • Thanks 1

Share this post


Link to post
Share on other sites

20190315_085404.jpg

20190315_085712.jpg

1 hour ago, SonsOfIrony said:

How about we keep the offensive, borderline racist words like "ricer" off our official documents, and leave them to the conversations between chew spittin, busche lite swillin, good ol boys.

 

See also, "that's our word, you can't use it"

Actually, I never thought of that as being racist. ever.

sorry. 

You are right though.

Share this post


Link to post
Share on other sites
2 hours ago, Huggy said:

 

I can tell you that I went from 2.5 to 3 inch, same brand muffler cherry bomb, same routing, etc and it got much louder

Curious,  to the ear, or a meter? 

  • Like 1

Share this post


Link to post
Share on other sites
2 hours ago, SonsOfIrony said:

How about we keep the offensive, borderline racist words like "ricer" off our official documents, and leave them to the conversations between chew spittin, busche lite swillin, good ol boys.

 

See also, "that's our word, you can't use it"

I usually find Asians to be well down the list of fragile sub-groups. :) 

 

Would this be Hiaced out?

https://www.japan-partner.com/Auto/22404/Toyota/HIACE+VAN/car-for-sale.html

 

Here's an interesting article:

https://ultimatemotorcycling.com/2018/04/01/laguna-seca-ends-sound-enforcement-regulations-win-win-for-motorcyclists/

 

http://quiethorsepower.com/mufflers.html

Edited by mender

Share this post


Link to post
Share on other sites

That is a cool setup, that still may not pass. You want to be down in the mid-80s to be certain.
side_914-6.jpg

  • Like 1

Share this post


Link to post
Share on other sites
1 hour ago, Bill Strong said:

Actually, I never thought of that as being racist. ever.

sorry. 

You are right though.

 

I actually planned to green font that post, but decided leaving it as is would be more fun.

 

I also had never considered the racial undertones of that particular coloquealism until someone of far greater knowledge than myself who I respect explained to me the derogatory origins of the phrase, and why its best not to use it.

  • Like 1

Share this post


Link to post
Share on other sites
37 minutes ago, mender said:

I usually find Asians to be well down the list of fragile sub-groups. 

 

Better to be safe rather than sorry.  There are millennials of all nationalities.

  • Like 1

Share this post


Link to post
Share on other sites
1 hour ago, JDChristianson said:

Curious,  to the ear, or a meter? 

Never been to a metered track.

Share this post


Link to post
Share on other sites

Editorial comment:

 

15 minutes from my shop, a new track will be starting construction this spring. The opposition to the track has been fierce by a particular person who made it her life mission to stop or stall this track. Much fear-mongering, questionable "facts" and "studies" and outright lies were used, along with political and economic ties to delay the process. At the public hearing, trumped-up (is that now an offensive term? ;)) claims of potential damage to breeding cow operations, the desire to preserve the quiet of the countryside that neighboring people consider sacrosanct, and of course the lies: that the track is really a front for the local Hell's Angels branch for drugs and prostitution and a base for property crime.

 

The last is laughably false, but the noise claims were quite effective. However, very few of the people who didn't have a vested interest in maybe getting a cash settlement to buy them off (rumours that $20,000 cash under the table would have shut up the loudest protesters) were fooled by the claims that the cows cared one way or another about noise, and even fewer believed the ones pleading that the track would disturb their peaceful country existence. 

 

The track is being built directly beside the busiest highway in Alberta. IIRC , the traffic volume is 26,000 vehicles passing that point daily. I stopped my Duramax truck adjacent to where the track will be, across the road from one of the properties that was owned by  the people claiming to be there for the solitude and silence of the country and opened my window with the engine idling. There was a noticable percentage of time that I couldn't hear my diesel engine running because of the traffic noise. 

 

There were herds of cows visible in the fields beside the highway calmly munching away that were part of highly touted breeding operations. No reaction at all despite a few coal-rollers large diesel pick-up trucks with open exhaust snorting by. Probably the same cow breeds that live under the flight paths of airports.

 

The political and economic ties were the most effective. A shut-in well on the site suddenly became very valuable and caused a major delay and significant cost in redesigning the track to allow for setbacks that usually apply to public facilities rather than a privately owned and run development. 

Share this post


Link to post
Share on other sites
6 minutes ago, SonsOfIrony said:

 

Better to be safe rather than sorry.  There are millennials of all nationalities.

I understand, I raised my children to be aware and proud of their Viking heritage.

 

Vikings never had horns on their helmets yet this is one of the most universally used visual in identifying them, and I for one am outraged by that travesty and insist that all references to horned helmets be erased from the records. I have urged my children to take up their axes and continue our tradition of annihilating whatever we get the hankering to chop up. It's our ancestral right.

 

And don't be calling others Valkyries, that's ours too. :)

  • Like 1
  • Haha 1

Share this post


Link to post
Share on other sites

Does this mean I cannot wear my Haggar the Horrible helmet in my Nissan Titan pickup any more? Man I just cannot ever seem to get this P.C. Stuff straight. 🙄😏

 

12 minutes ago, mender said:

I understand, I raised my children to be aware and proud of their Viking heritage.

 

Vikings never had horns on their helmets yet this is one of the most universally used visual in identifying them, and I for one am outraged by that travesty and insist that all references to horned helmets be erased from the records. I have urged my children to take up their axes and continue our tradition of annihilating whatever we get the hankering to chop up. It's our ancestral right.

 

And don't be calling others Valkyries, that's ours too. :)

 

  • Haha 2

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...