I'm heading for Laguna for some seat time with NCRC in early December. They will be enforcing a 94 dB sound limit, monitored at turn 5. I don't know what distance the measurement is taken from, but does anyone have any idea if the car will pass? The stock exhaust is on the car. Thanks.

 

i am at LS very often.
i am afraid to inform you that you have NO WAY IN HELL to ever pass sound. the limit is 92db wiht NCRC, not 94 i dont think. chk with dave mill again.

my STOCK 997GT3 is measured at 98db, when i used turn down and stuffed foam into the intake i got 95.4 dB. ask other cup car drivers, they have a HUGE muffler OUTSIDE of the rear bumper to get it to pass.

it wont be easy.

 

At that rate, what will pass? Thought it might be tough and was researching alternate exhaust, but had someone who runs cup cars tell me it may pass so thought I would put it out there. Cup exhaust is supposedly 110 dB and quiet system from PMNA is 103 dB, but I don't how/where they measure that from. It was Dave that told me 94, but I will ask again...maybe I heard wrong (too much time at 110?!)

 

If you go to the POC site and look at the photo gallery from 2006 Laguna Seca (be sure to look at 2006 not 2007) and you will see lots of the muffler set ups necessary.

No way will a stock exhaust work. In addition to the muffler you need to put foam in the intake.

http://www.porscheownersclub.org/

 

Kevin,

What a great reference, I can't believe some of those set ups! Hope your car is ready to go for Willow!

JCM

 

John - we're 98% sure it will be done - being reassembled now.

See you there!

 

thanks for all the information. some very creative approaches. any idea how much power loss some of these systems result in? Why foam in the intake? I will try to contact some of the folks that have gone through the effort via a new thread. Cheers.

 

Wanted to get this back up for some updated pics of Laguna Seca exhaust

any new galleries out there that have some good pics or does anyone on here have a laguna muffler setup they would be willing to share?

 

Bob @ Competition Motorsports will make you a custom laguna exhaust that will pass sound. Its a investment but you will have it for years and will be able to still drive laguna

 

I will be at laguna tomorrow.
Will see if I can go find him and have a chat

Thanks

 

Some info I've come across for the earlier cups is a major difference in the factory quiet (103db vs the 110db for the std) systems is the header diameter. If you can start with a quieter header perhaps you would need less appliance hanging on the back of the car.

Have no idea of the exact dimensions, but I wonder if a street header would be a good place to start...

anyone have a pic of a good design that passes at laguna (not a glued on rube Goldberg deal?..)

 

if u run street gt3 cat back, u will pass

 

I don't know if this helps, but a track in Phx has just reopened with a 94db noise restriction measured 50' from the track. we have found that a stock 996 GT3 exhaust will pass but a 997 GT3 RS will blow a range of 98db - 100 db. (tested three different cars)
The stock 997 cups are blowing 102 - 104 db (tested three different cars)
I have just recieved info from PMNA that thier pre silencer for the 997 cups will get the cups down to the 997 GT3 RS levels.
We have tried the vector cones with turn down tips on the cups and that made a wopping 1 db change so dont waste your money trying that.
The shop I use has designed a system that adds a set of Burns mufflers to a 997 cup and it is blowing 90 db.
Everything is tucked under the fenders and bumpers and you will have to add a heat shield to the rear bumper.
I know Bob Fieta's system works and is easier to take on and off, but if you want something hidden call Doug Chernis @ RaceTechnik in Mesa AZ.

 

^ how much is racetechnic system and how much is bob fieta system?

any pwr loss?

akropovich works, mikymu tested on a 07 cup at laguna, though I think it is nearly 10k retail

 

You need to contact them directly for pricing