Gadd

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

parid

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

Gadd

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

gracer7-rx7

iTrader: (16)

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.

Silkworm

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!

Jross427

iTrader: (13)

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

Silkworm

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

Gadd

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

John Magnuson

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!

jantore

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

Jross427

iTrader: (13)

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.

Silkworm

ah yeah gotcha, I don't do enduros so I don't have to worry about that so much.

PaulC

Gadd

Well, we'll give this a go.






Paul

Gene

iTrader: (1)

Damned noise *****!



Also found this:

https://www.rx7club.com/race-car-tech-103/black-flagged-laguna-seca-noise-129191/

primerGrey

iTrader: (13)

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!

Gadd

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.






Paul

rotoober

iTrader: (3)

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.

Natey

iTrader: (19)

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.

jantore

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

Gadd

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

gracer7-rx7

iTrader: (16)

Did Chuck have any noise problems at Laguna?

Gadd

Nope. I think the only difference is he's got an OEM cat.


Paul

gracer7-rx7

iTrader: (16)

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.

primerGrey

iTrader: (13)

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.

13bdatsun

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