C4SGRPDK

Hello,

I have a 991 GT3 with a GMG center bypass. I bought the car with it and the previous owner did not have the OEM center anymore.

I lap at tremblant at the end of may and there's a 92db sound limit.

I was wondering if the car could pass the sound as is, or if I needed to fab some turn downs, or if turn downs would even be enough?

Thanks!

Guest89

Depends on a wide variety of factors, of course.

I did a track day at a sound limited track last year with a GMG bypass; I used a crimped piece of coathanger to force the valves closed even at high RPM.

24Chromium

For what it's worth, I've yet to see a stock GT3 of any generation pass sound at Laguna Seca.

ipse dixit

You could look into this solution by our very own Mech33.

A bit complicated, but it is a solution.

PierreTT

I went to Tremblant a few times last year

Stock I was OK.

Dunno with GMG bypass though...

Nodrip

I have been flagged around 100db once, with my stock GT3 (GMG is probably louder...)

But PierreTT is saying that it's allright...
If they changed/improved the sound control this year, you are probably screwed!

C4SGRPDK

Don't think I could do this as tremblant takes 2 measurements, one is fixed the other is moving around the track.

FWIW, last year I ran my .2RS with fabspeed headers, side bypass, stock center and I was flagged at 96 or 97 db on a cloudy day.

I guess I'll bring turn downs, and if it doesn't do the trick I'll maybe force the valves to the closed position, for the event, then I would look for stock center exhaust.

I'll buy a sound meter to make sure and report before the event

Pierre or any tremblant guys, do you know at what distance they take the measurements?

John@Fabspeed

We offer bolt on turndowns that cut down the decibels a good bit. May be helpful to pick up a set sometime to easily throw on at the track if needed.

PierreTT

I dont know... I usually try to be smooth and slow (not hard for me ) for the first session in the morning and get harder/louder after. I believe they pay more attention the first session of the first day (human nature) but it is pure speculation... Worst when it is cloudy for sure.

These Fabspeed Turndown would fit a 991RS as well John??

John@Fabspeed

From what we have seen yes they will. However, these turn down require either Fabspeed exhaust system or a new tip backing plate like the one included in the picture below (as you can see the factory tips are a bit unremovable haha).



The Turndowns themselves are $295, and with the backing plate would be $495.

Mechanicalrepair

Yes standard car and I got flagged at a race track at 102db without the sport button pressed.

Carl

Mech33

Downturns are good for -3 to -4 dB.

reidry

I also run the GMG and it is over 100 dB at full blast.

I have run at Atlanta Motorsports Park, which is restricted by safety wiring the valves shut. Safety wire takes maybe 10 min and comes off in 1.

Ryan

kfmcmahon

I was at Tremblant in my ZR1 with Long tubes and no cats there last year.

My car is very, very loud (in a good way), but has the butterfly valves above 3000 rpm, which I removed the vacuum lines and just slightly lifted on the front straight where I heard the sound check was---no problem all weekend!!

There was a race prepped 430 Scud , but had those curved tail pipes pointing to the LEFT of the car and he was fine...not nearly as loud as my Vette so he had no issues.

You will LOVE this track...one of my new favorites...lots of off camber, blind up/downhill turns and beautiful views of the surrounding mountains and ski area.

lots of great places to eat in the pedestrian village. Hiking, mountain biking, sailing, motor boating, fishing etc... all at the ski area

Hopefully, the owner or his son will be there that weekend so you can see his ridiculous collection of Ferrari's


http://www.theglobeandmail.com/repor...rticle4092531/

C4SGRPDK

Yeah Tremblant is amazing!

I have been going at every PCA DE events for the past 2 years, but it will be the first time with the 991 GT3, hence the concern.

I did some digging and they use the dba scale. 92 db at 50ft.

I guess I better start looking for an oem center! any one have one for sale?

Can there be problems if the car is run with the valves in the closed position?