FNBADAZ06

A new track here in AZ was running sound test for various cars in preperation for opening up for business, with the track limiting the exhaust db level to 94 maximum to satisfy noise concerns with the local neighborhoods. They setup a sound metering station at the mid point of the back straightaway.

My otherwise stock 2006 C6 Z06 has the OEM ZR1 mufflers and X-pipe with factory exhaust manifolds and cats....something similar to what the new 2011+ Z06's are equiped with from the factory.

To my suprise, my car failed the test with a 97 db reading at WOT going down the straightaway.
So, with tracks with sound restrictions it looks like the newer factory bi-mode exhaust valves will need the vaccum lines to be disconnected and safety wired into the closed position.
The factory 2006-2010 C6 Z06 exhaust appears to just make it, as a friend's bone stock 2007 Z measured in between 92-93 db's.

I wonder what a factory ZR1 comes in at ?

How are other's dealing with noise restriction at tracks where this 94 db level is enforced ?



Funny thing is that this new track is situated on property that is adjoining to the World's largest active F-16 fighter jet training facility....Luke AFB !!!! How's that for noise restriction

gmccreary

Lift the throttle where it's being measured.

FNBADAZ06

They were specifically looking for anyone who was "sand bagging" the test. The back straighaway is 1591' + in length, so they had people listening and measuring a car's speed down the track....an area where a C6 Z06 would easily be in the low 120-125 MPH range when coming off the preceeding corner. I short shifted from 3-4th gear to keep the rev's lower but it didn't matter.

meldog21

I don't know how to turn off the open muffler feature on the C6 Z06 exhaust (I have a C5 Z06) but I have had experience at trying to make sound restrictions.

Laguna Seca is strict on noise allowed. I have seen many homemade exhaust adapters to make sound. The more simple designs are deflectors with 90 degree bends that shoot the exhaust away from the side of the track where the measurements are being taken (at Laguna the sound booth is on the right side of the track exiting turn 5).

After you figure out how to keep the exhaust in the quiet mode be prepared with something else like deflectors just in case. You don't want to spend the day trying to make something at the track (don't ask me how I know).

I have tried the lift/upshift method and didn't like it one bit. It totally screws with your lap times and entry to the next corner.

Get the exhaust to stay in quiet mode and build some cheap deflectors. It will work and you'll get to spend your time at the track having fun.

Dog

OCCOMSRAZOR

97 db seems really low. At Portland, the limit is 103 db. I got a warning at 102.7 a couple of weeks ago. I'm running headers, cats, and a Corsa Sport exhaust.

They limit to 93 db from 9:00 pm to 9:00 am. No night racing for me.

Nice to see a new track down there!

TMyers

The other thing to try is limit the amount the baffles open.

StKnoWhere

Something like this

FNBADAZ06

Yep.....I saw these as well.

Falcon

Can't weather conditions make a difference, too? Possible to pass one day, and fail on another?

FNBADAZ06

I could see where it might possibly make a small difference, but 97 db is quite a bit greater than the 94 limit. I'm guessing that with the flaps closed I'll give up roughly 10-15 peak rwhp but it should easily pass the noise test.

We will see, as I'll retake the test when they offer it again.

rbl

I'd tell the track to get real and I for one would not go there if I had to silence my car to the level of a cell phone.

A lawn mower makes a lot more than 94 dB and that certainly seems most unreasonable. Tracks should be up around 104 dB or it should not have been permitted.

NASCAR is up around 140 dB and common work environments allow more than that 4 hrs. a day.

Something is wrong about that I think.

Here is a good reference: Noise Level

dfinke23

This is why a lot of guys do a custom setup and turn the tips one way or the other. Most meter on the outside of the track so the tips are turned in.

harrydirty

Laguna Seca is limited to 92db I short shifted my first time there and tried running normally during the last session and did not get flagged.

Others driving c6z's have reported no problems running stock there, so I'll try running normally next time.

Apparently, the numbers are not the entire story; some cars may sound louder to our ears, but the microphones also are frequency biased and may pass those "louder" cars while our "quieter" cars will get flagged.

FNBADAZ06

It's not really the track's fault...they are attempting to play nice with the county supervisors and home owners, which forced the closure of the track after it was issued the permits and built. It's been in litigation for 8+ years, and following a successful rebuttal of the original law suit, the track is prepairing to re-open for use.

Some history on this track.....

http://www.azcentral.com/community/s...ceway0203.html

I think the track owners could legally give the bird to the Goodyear city officials and surrounding home owners, backed by the Supreme Court decision that favored the track and it's ownership, but the track is trying to be considerate.

AU N EGL

turn downs pointed away from the sound meters

FNBADAZ06

Well, this is a street car, with a full factory exhaust. I'm not going to attach turn downs on my OEM exhaust tips, and putting cutouts on the mid-pipe defeats the whole noise thing, I would think

AU N EGL

Do you want to drive on this track or not?

play by THEIR rules or don't play at all

FNBADAZ06

Who said I'm not playing by THEIR rules ????????????

A suggestion to use a product to keep the valves closed was offered.
Do you drive a street car on the track, or a dedicated track car ?
Show me a pic of your turn downs you use on noise restricted tracks

Dirty Howie

I went Laguna Seca few months back. I had no trouble the first day but got Black Flagged twice the next day


DH

Dirty Howie

My car is completely stock and so was another C6Z .... we both got multiple black flags. I liked the track but will not go back unless they change the DB level.


DH