Can a Radical run Laguna on a 92 db day?

[CharleyH]

I want to run my SR3 at Laguna Seca on a 92 db day. I purchased a "Laguna Muffeler" from Radical, but in doing some research it looks like this Muffeler is rated at 98db. I don't know how the Muffeler is tested or how that number applies to measured sound at the track. I was thinking of having a 90 degree elbow fabricated that turns to the left and up. How have others made the sound limit at Laguna?

Thanks for the help,

Charley

[David Ferguson]

You have a volume control under your right foot. Shift early, shift often.

Second, they can't get a valid reading if you are near another car -- so then you don't have to lift (what we used to call "paying respect to the sound meter").

The 90deg turnout may help -- but often the intake system makes almost as much noise as the exhaust.

[Jnovak]

Just make sure that your exhaust it pointed totally away from the meter, use a muffler and you will be fine.

[terryeaton]

Use the elbow and drill a series of holes in the outside of the 90. I have used three by three. Also when in doubt short shift coming out of five. If its foggy, then take more care.

[Graham Rankin]

I can only speak from personal experience with the Atlantic car, and as Dave points out induction noise can be just as problematic. For us, the ONLY muffler that makes the numbers is the Quiet Horsepower from Pete Weber. Not sure if you up for that expense, but 92db is a tough number in any sports racer / formula car. Yes, you can back off well before the noise meter but thats a real PITA and does nothing for your lap. A turn out may help. Good Luck

[AGMelv]

Running a google image search on "laguna seca noise measuring" can give you some ideas - but it's mostly just pretty hilarious photos.

http://rennlist.com/forums/attachmen...-exhaust-2.jpg

image search: https://goo.gl/Kc6hbe

[Jnovak]

Running a google image search on "laguna seca noise measuring" can give you some ideas - but it's mostly just pretty hilarious photos.

http://rennlist.com/forums/attachmen...-exhaust-2.jpg

image search: https://goo.gl/Kc6hbe

Note that the outlet is facing the left side of the car. LOL.

[BeerBudgetRacing]

Something can be learned from this......

http://i.imgur.com/zWcUCvZ.jpg

[DanW]

Laguna is a "special" place.

Factors that affect sound level that are out of your control:

Weather
Air density, humidity, overcast cloud level, fog. The clouds and fog reflect the sound back to the ground. Higher air density, the more power you make, more noise you make.

Geography
The microphone is drivers right, pointed at 90deg to the line of the track, about 50ft from the track edge as the track takes you up the hill.

Drivers left is a sandy dirt embankment that may reflect the sound from your exhaust.

There are some things you can do.
Your car produces sound from the exhaust, intake, gearbox, final drive, even loose bodywork. All the noise produced is cumulative to the sound pressure meter.

The stock bike muffler that was built for that Suzuki motor is your best bet for exhaust. Directing exhaust to the left at an angle helps.

The stock airbox for your motor is a good place to start. Use the OEM paper filter element, not a K&N. Duct your air intake into the cockpit if you can. Lining the duct with flexible perforated "sonex" material may help. Make sure it's installed so it does not get sucked into your throttle bodies. Its like a muffler for your intake.

Gearbox. If your gearbox or final drive howls, Redline shockproof may help. It has plastic beads in it to cushion the gearmesh. Not sure if it is recommended for your box though.

Loose bodywork can also cause issues.

Cross to drivers left as you exit Turn 5. Distance from the mic is your friend.

I have two club fords. One makes 92dBA with a Coast 2x14 muffler filled with fiberglass. Carb has a filtered intake. The other makes 100dBA with a Supertrapp glass packed muffler. The intake roar seems to be the problem so I'm making an airbox lined with sonex material. Two cars, same motor, same K&N air filter. Go figure.

92dBA is achievable, but do your homework. 93dBA and your are on the trailer. On track days, you can ask for a sound check. They will let you try your car for three laps. If you are over, you are black flagged and informed of your sound level. You must go to the paddock and make a change to reduce the noise. You are allowed to attempt another three laps. If you fail again, you are done for the day.

Good luck.
Regards,
Dan

[jaltaman]

I race F1000 and we fought noise issues for years at both Pacific Raceways and Laguna Seca until we implemented the "Three Washers" trick. This took 4 dB off our readings and didn't seem to impact performance, either.

Just get a separate exhaust tip made and weld on three large washers positioned at the end of the exhaust tip like a tee-pee with the tip at the back of the opening as shown in the links below.

Clamp it on and point it to the left for Laguna Seca and you will be fine - no lifting necessary.

https://drive.bitcasa.com/send/5MZfq...DgNrMYPATG9Xd3

https://drive.bitcasa.com/send/JkAKd...VqqA_0SGNoQ3Nz

https://drive.bitcasa.com/send/gp9fd...D-lVhNz33yTxwc

[CharleyH]

Thank you all for all of the great ideas.

Charley

[abaileyracing]

I have a Laguna Spec Radical SR3 muffler I would be willing to sell. It even has a turn away that can be added to it. PM me if interested. This muffler should get you under the 90db.

[CharleyH]

I have a Laguna Spec Radical SR3 muffler I would be willing to sell. It even has a turn away that can be added to it. PM me if interested. This muffler should get you under the 90db.

Thank you for the offer. I have the quiet muffeler from Radical but they are rated at 92db. I put a 90 degree elbow on it and didn't have any problem making sound on a 92 db day.

Charley

[Etchhead]

Thank you for the offer. I have the quiet muffeler from Radical but they are rated at 92db. I put a 90 degree elbow on it and didn't have any problem making sound on a 92 db day.

Charley

Congrats Charlie- I blew sound all day on my last visit and learned how to get by at the cost of lost time. I'm in the process of getting something fabbed up myself to include turn away.

[CharleyH]

Congrats Charlie- I blew sound all day on my last visit and learned how to get by at the cost of lost time. I'm in the process of getting something fabbed up myself to include turn away.

I was concerned that I wouldn't make sound so for the first half of the day I was trying to cary as much speed as possible through 5 and then used 3/4 throttle past the sound booth. As the day went on I started giving more and more throttle until I was at full throttle. Never got flagged for sound. I was a little surprised to tell you the truth