Race Car Tech Discuss anything related to road racing and auto X.

Exhaust turn-downs for Laguna Seca

Old 10-20-08, 11:23 PM
  #1  
Warming the planet.
10 Year Member
Thread Starter
 
Gadd's Avatar
 
Join Date: Dec 2004
Location: Chico, CA
Posts: 843
Likes: 0
Received 0 Likes on 0 Posts
Exhaust turn-downs for Laguna Seca

Has anyone come up with a clever solution to defeat the noise police at Laguna?

I have been meatballed for noise with a DP, OEM cat and a RB duel tip. Now I have replaced the OEM cat with a high flow, and the car is quite a bit louder, and I really don't want to be lugging up the hill in fifth, pointing all the corvettes by. I was going to go by the local exhaust shop and see if they have some 2 1/2" 90s that will slip over the tips, but I know I'll bust my shins no them at some point during the day. Have any of you smarty pants guys come up with a more "elegant" fix?

Paul
Gadd is offline  
Old 10-20-08, 11:59 PM
  #2  
ChumpCar**Apex of Failure
10 Year Member
 
Join Date: Jul 2002
Location: Oregon
Posts: 259
Likes: 0
Received 0 Likes on 0 Posts
What is the DB limit down there anyway? I was thinking about visiting once next season and I'd hate to make it all the way down there and get meatballed. My fd is probably on the louder side. 3" with a high flow
parid is offline  
Old 10-21-08, 08:19 AM
  #3  
Warming the planet.
10 Year Member
Thread Starter
 
Gadd's Avatar
 
Join Date: Dec 2004
Location: Chico, CA
Posts: 843
Likes: 0
Received 0 Likes on 0 Posts
There is a STRICT 92 dBA sound limit for all open track days, as far as know. If you are over the sound limit you will be given one chance to fix it. After that, you will have to sit out. The sound level monitoring is all done by the county, and there is zero tolerance.


Paul
Gadd is offline  
Old 10-21-08, 11:39 AM
  #4  
needs more track time
iTrader: (14)
 
gracer7-rx7's Avatar
 
Join Date: Mar 2006
Location: Bay Area CA
Posts: 7,834
Received 14 Likes on 13 Posts
Not sure if he ever posted pics but try searching for 'John Magnuson' Laguna setup. I can't seem to find it right now.

He did a special muffler configuration that places a second muffler running parallel to the rear bumper. I see Spec Miatas and other race cars with similar setups now and then. Pretty funny to look at but I suppose it works.
gracer7-rx7 is offline  
Old 10-21-08, 12:10 PM
  #5  
Has been.. hangin' around
10 Year Member
 
Silkworm's Avatar
 
Join Date: Mar 2001
Location: Milpitas, CA
Posts: 2,618
Likes: 0
Received 0 Likes on 0 Posts
That's basically what I did, a slip on over my stock exhaust tip that has a 90* bend and a super trapp on the end. Kills the power though. The other issue is it would be better to be on a flange, the slip on just rotates. Or you could mount a hanger somewhere to help keep it where you want it.

Ghetto fabulous!
Silkworm is offline  
Old 10-21-08, 02:57 PM
  #6  
Going Nowhere
5 Year Member
iTrader: (13)
 
Jross427's Avatar
 
Join Date: Oct 2007
Location: sacramento
Posts: 462
Likes: 0
Received 0 Likes on 0 Posts
on our 1st gen, we did what was stated above, ran a extra muffler along the rear bumper pointing out to the driver's side. this style exhaust will clear you at infineon, laguna, and the 25 hour if you are racing because all the sound checks are on the passengers side
Jross427 is offline  
Old 10-21-08, 05:44 PM
  #7  
Has been.. hangin' around
10 Year Member
 
Silkworm's Avatar
 
Join Date: Mar 2001
Location: Milpitas, CA
Posts: 2,618
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Gadd View Post
There is a STRICT 92 dBA sound limit for all open track days, as far as know. If you are over the sound limit you will be given one chance to fix it. After that, you will have to sit out. The sound level monitoring is all done by the county, and there is zero tolerance.


Paul
I've heard it going as low as 90db in some cases. I wasn't aware it was one chance, last time I ran laguna (admittedly 3+ years ago) it was 3 tries to fix before you were done.

Jross, do you find the extra muffler necessary for non LSIR events on your car? I don't need anything other than my Magnaflow for 103db at Infineon or Thill. And my car is pretty freaking loud

PaulC
Silkworm is offline  
Old 10-21-08, 09:52 PM
  #8  
Warming the planet.
10 Year Member
Thread Starter
 
Gadd's Avatar
 
Join Date: Dec 2004
Location: Chico, CA
Posts: 843
Likes: 0
Received 0 Likes on 0 Posts
Thanks for the responses guys. I may have access to a db meter, maybe I'll experiment with a few different configuration the next time I'm at THill. I won't be at Laguna until December.

Paul
Gadd is offline  
Old 10-22-08, 01:02 AM
  #9  
Rotary Enthusiast
10 Year Member
 
John Magnuson's Avatar
 
Join Date: Dec 2002
Location: San Diego, CA
Posts: 1,147
Likes: 0
Received 0 Likes on 0 Posts
You'll definately need a turn out at least. The turnout helps a lot.

When I went single turbo I needed two resonators, one large muffler and one turnout to pass the 90db limit.

If the conditions were right (some days sound just travels better) my STOCK FD with a racing beat dual tip muffler, downpipe and STOCK cat would sometimes register over 90bd.

The fact is the sound limit there is just plain ridiculous. I've seen 100% stock sports cars like Vipers, Porsches, Ferraris and Ford Mustangs/ Ford GTs get flaged for sound.

Good luck!
John Magnuson is offline  
Old 10-22-08, 02:17 AM
  #10  
Rotary Enthusiast
10 Year Member
 
jantore's Avatar
 
Join Date: May 2003
Location: Norway
Posts: 904
Likes: 0
Received 1 Like on 1 Post
Originally Posted by John Magnuson View Post
You'll definately need a turn out at least. The turnout helps a lot.

When I went single turbo I needed two resonators, one large muffler and one turnout to pass the 90db limit.

If the conditions were right (some days sound just travels better) my STOCK FD with a racing beat dual tip muffler, downpipe and STOCK cat would sometimes register over 90bd.

The fact is the sound limit there is just plain ridiculous. I've seen 100% stock sports cars like Vipers, Porsches, Ferraris and Ford Mustangs/ Ford GTs get flaged for sound.

Good luck!
hehe no ****, most of those cars have a sound limit higher then 90 db. Most of these will be above 96db in the registration document. The FD is registerd with 88db at 4500 rpm. And a stock FD is rather quiet, and that's 4db bellow the sound limit at Laguna Seca. Thank god we almost never have that sound limit here in norway. The lowest is 90 db thoug, but this is on sundays. Other then that we have 95 and 100db limits. My FD with straight exhaust, veilside catback and a singel turbo was at 99.8db. My new 4" exhaust with Coastfab mufflers are bellow 95db But still sounds sweet.

JT
jantore is offline  
Old 10-23-08, 11:36 PM
  #11  
Going Nowhere
5 Year Member
iTrader: (13)
 
Jross427's Avatar
 
Join Date: Oct 2007
Location: sacramento
Posts: 462
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Silkworm View Post
I've heard it going as low as 90db in some cases. I wasn't aware it was one chance, last time I ran laguna (admittedly 3+ years ago) it was 3 tries to fix before you were done.

Jross, do you find the extra muffler necessary for non LSIR events on your car? I don't need anything other than my Magnaflow for 103db at Infineon or Thill. And my car is pretty freaking loud

PaulC
no, unless it is the 25 hour at thunderhill, the car has manly been used for that purpose, and makes some side trips. you have to remember, both at laguna and the 25 hour are rather chilly. the 25 hour is cold as hell, and laguna is only a couple of miles off the coast. sound travels better through cold climates.
Jross427 is offline  
Old 10-23-08, 11:42 PM
  #12  
Has been.. hangin' around
10 Year Member
 
Silkworm's Avatar
 
Join Date: Mar 2001
Location: Milpitas, CA
Posts: 2,618
Likes: 0
Received 0 Likes on 0 Posts
ah yeah gotcha, I don't do enduros so I don't have to worry about that so much.

PaulC
Silkworm is offline  
Old 11-29-08, 09:50 PM
  #13  
Warming the planet.
10 Year Member
Thread Starter
 
Gadd's Avatar
 
Join Date: Dec 2004
Location: Chico, CA
Posts: 843
Likes: 0
Received 0 Likes on 0 Posts
Well, we'll give this a go.


Name:  100_0210.jpg
Views: 442
Size:  78.8 KB



Paul
Gadd is offline  
Old 11-29-08, 10:10 PM
  #14  
10 lb. boost, 5lb. bag
10 Year Member
iTrader: (1)
 
Gene's Avatar
 
Join Date: Mar 2001
Location: New York, NY
Posts: 1,076
Likes: 0
Received 0 Likes on 0 Posts

Last edited by Gene; 11-29-08 at 10:12 PM.
Gene is offline  
Old 11-30-08, 02:10 AM
  #15  
needs more track time...
iTrader: (13)
 
primerGrey's Avatar
 
Join Date: Sep 2005
Location: Menlo Park, CA
Posts: 307
Received 8 Likes on 3 Posts
Originally Posted by Gadd View Post
Has anyone come up with a clever solution to defeat the noise police at Laguna?

I have been meatballed for noise with a DP, OEM cat and a RB duel tip. Now I have replaced the OEM cat with a high flow...

Paul
I have the same configuration. I just do a lazy 3-4 shift going past the mic coming out of turn 5 - that seems to be the only place they ever put the microphone and it is almost perfectly located at the shift point. Not ideal, but easy.

I am planning to build a turn-out as you've already posted though. Let us know how it turns out!
primerGrey is offline  
Old 12-11-08, 09:20 PM
  #16  
Warming the planet.
10 Year Member
Thread Starter
 
Gadd's Avatar
 
Join Date: Dec 2004
Location: Chico, CA
Posts: 843
Likes: 0
Received 0 Likes on 0 Posts
Just the turn downs didn't work, I got meatballed for a 97db right away. I didn't have that many opportunities to drive Thursday, the day was full and I was out coaching almost every session. So I made some changes for Monday, and there was no novice group so I was able to play most of the day. The new iteration worked! Got a 92.2 at a sound check. It almost set the car on fire, but once all the close plastic melted away, all was good.

Name:  100_0214.jpg
Views: 444
Size:  28.9 KB

Name:  100_0215.jpg
Views: 414
Size:  78.2 KB


Paul
Gadd is offline  
Old 12-12-08, 11:09 AM
  #17  
one part from Nirvana
10 Year Member
iTrader: (3)
 
rotoober's Avatar
 
Join Date: Dec 2004
Location: in a van by the river
Posts: 380
Likes: 0
Received 0 Likes on 0 Posts
If I can't get out to the track, I'll sell you parts that will get you booted out! That will teach you to go to Laguna without me.

Last edited by rotoober; 12-12-08 at 11:11 AM.
rotoober is offline  
Old 12-12-08, 11:49 AM
  #18  
Playing Well
iTrader: (19)
 
Natey's Avatar
 
Join Date: Aug 2004
Location: Santa Cruz
Posts: 3,889
Received 56 Likes on 44 Posts
Get a a 90 degree elbow that fits over your exhaust tip. Drill two holes all the way through one end of it.
Take two nuts and bolts that will fit through the holes you just drilled, and insert them so that the bolts make an "X" at the exhaust tip.

Stuff some high-quality steel wool into your new 90 degree tip, and put the bolts in, so that the steel wool can't escape through the "X".

Aim your elbow to the LEFT, because the sound booth is on the right side of the track, between turns 5 and 6.

Worked for me...until my elbow melted. If I would have had a higher-quality elbow (I was using a downpipe for the rain gutters of a house) like I have now, I would have been fine all day.


For the record: Cheap bastard intake, downpipe, Bonez hi-flow cat, PFS exhaust.

Last edited by Natey; 12-12-08 at 11:51 AM.
Natey is offline  
Old 12-12-08, 03:43 PM
  #19  
Rotary Enthusiast
10 Year Member
 
jantore's Avatar
 
Join Date: May 2003
Location: Norway
Posts: 904
Likes: 0
Received 1 Like on 1 Post
Why don't you just talk to coast fabrication(www.coastfab.com). They build and sell racing mufflers for le mans, indy, cart and so on. They guaranti DB limits on there mufflers. I did run a 4" straight exhaust with 1 round coast fab mufler in the middle and a magnaflow flat 4" straight trough muffler at the end on my Large Bridge Port turbo engine and i had no problem with sound. Actually it was alot more quieter then my old setup with a 3" straighth exhaust with just a veilside catback at the end. I think we messured mine at 93db with the 4" exhaust with 1 coast fab muffler and magnaflow muffler

So i would guess with a 3" exhaust and 2 coast fab muflers u should be bellow 92 db without sacrifising performance.

JT
jantore is offline  
Old 12-14-08, 09:07 PM
  #20  
Warming the planet.
10 Year Member
Thread Starter
 
Gadd's Avatar
 
Join Date: Dec 2004
Location: Chico, CA
Posts: 843
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by jantore View Post
Why don't you just talk to coast fabrication(www.coastfab.com). They build and sell racing mufflers for le mans, indy, cart and so on. They guaranti DB limits on there mufflers. I did run a 4" straight exhaust with 1 round coast fab mufler in the middle and a magnaflow flat 4" straight trough muffler at the end on my Large Bridge Port turbo engine and i had no problem with sound. Actually it was alot more quieter then my old setup with a 3" straighth exhaust with just a veilside catback at the end. I think we messured mine at 93db with the 4" exhaust with 1 coast fab muffler and magnaflow muffler

So i would guess with a 3" exhaust and 2 coast fab muflers u should be bellow 92 db without sacrifising performance.

JT


Sounds cool, but I'm a poe poe man that wants to go faster.

This video is from "ccanepa50's" car. I would title it "Chuck waiting for my slow a$$."

Notice how much more speed he carries through T3 and T4.




Paul

Last edited by Gadd; 12-14-08 at 09:33 PM.
Gadd is offline  
Old 12-15-08, 11:55 AM
  #21  
needs more track time
iTrader: (14)
 
gracer7-rx7's Avatar
 
Join Date: Mar 2006
Location: Bay Area CA
Posts: 7,834
Received 14 Likes on 13 Posts
Did Chuck have any noise problems at Laguna?
gracer7-rx7 is offline  
Old 12-15-08, 06:22 PM
  #22  
Warming the planet.
10 Year Member
Thread Starter
 
Gadd's Avatar
 
Join Date: Dec 2004
Location: Chico, CA
Posts: 843
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by gracer7-rx7 View Post
Did Chuck have any noise problems at Laguna?
Nope. I think the only difference is he's got an OEM cat.


Paul
Gadd is offline  
Old 10-29-09, 09:16 PM
  #23  
needs more track time
iTrader: (14)
 
gracer7-rx7's Avatar
 
Join Date: Mar 2006
Location: Bay Area CA
Posts: 7,834
Received 14 Likes on 13 Posts
Speaking of sound at Laguna.... Finally ran it on Monday 10/26/09.

Running a small street ported motor, 99 twins, DP, SMB muffler + metal cat midpipe, RB dual tip. Hit 97 DB at full tilt going up the hill near the sound meters. I was chasing a Lamborghini Murcielago LP640 and a C6 ZR1 and could bear to back off.

Everyone was getting hit with sound meatballs that day. Even people who previously didn't have problems. I think the climactic conditions made noise louder or travel further. Still 97 db is a bit too loud.
gracer7-rx7 is offline  
Old 10-31-09, 08:18 PM
  #24  
needs more track time...
iTrader: (13)
 
primerGrey's Avatar
 
Join Date: Sep 2005
Location: Menlo Park, CA
Posts: 307
Received 8 Likes on 3 Posts
Alberto, I also have a RB dual tip, and had this 90 deg made up at a local muffler shop for about $50 bucks. This worked great at Laguna, although I don't remember my "before" db's. It fits down inside the inner RB pipes. Note the jam nuts to keep it tight.

It takes some wiggling to get it loose at the end of the day, but isn't that difficult.
Attached Thumbnails Exhaust turn-downs for Laguna Seca-ground-1.jpg   Exhaust turn-downs for Laguna Seca-ground-2.jpg   Exhaust turn-downs for Laguna Seca-car-1.jpg   Exhaust turn-downs for Laguna Seca-car-2.jpg  
primerGrey is offline  
Old 11-01-09, 05:25 PM
  #25  
Junior Member
 
Join Date: Sep 2009
Location: cen cal
Posts: 25
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by John Magnuson View Post
You'll definately need a turn out at least. The turnout helps a lot.

When I went single turbo I needed two resonators, one large muffler and one turnout to pass the 90db limit.

If the conditions were right (some days sound just travels better) my STOCK FD with a racing beat dual tip muffler, downpipe and STOCK cat would sometimes register over 90bd.

The fact is the sound limit there is just plain ridiculous. I've seen 100% stock sports cars like Vipers, Porsches, Ferraris and Ford Mustangs/ Ford GTs get flaged for sound.

Good luck!
stock s2000s post 94db there consistently turnout is required for ita/x/specrx7 cars there. you may want to find a muffler that you can have as your laguna setup. spec racer fords do this as well as a ton of other people i know that race there etc
13bdatsun is offline  

Thread Tools
Search this Thread
Quick Reply: Exhaust turn-downs for Laguna Seca


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: