Ducati1199

Anyone happen to have any real world sound levels at LS with side muffler bypass on a 991.2 RS? I'm reliably informed by @OrthoJoe that his totally stock exhaust, plus GPS, plus turn-away pipes gets him at or under 88dB. Would valved, Fabspeed side deletes, OEM center muffler, gps, and turn-away pipe get anywhere close to 92dB? Just a shot to see if anyone is running the same / similar set up to me and what happened at LS? Other options include short shifting, steering left and lifting past the sound booth so trying to verify if spending the money on a gps is worth it with my set up. Many thanks,

Mech33

Talking to a 997 GT3 owner that runs Laguna with the GPS + side deletes on an OEM center muffler with turn pipes, he claims he can pass 90 dB days. So my guess is you will be able to squeak by with side deletes.

Either way, the GPS will make the car WAY quieter going up the hill, so at a minimum you'd be able to go faster there (if not full throttle).

RDCR

My experiences FWIW:

Side Deletes: I blew a 94 twice with Soul valved side deletes and OEM center along with soul silenced turn downs and track nanny. This is on a .1 GT3. I actually thought I was fine with that setup earlier in the day but in later sessions any full throttle acceleration out of 5 going over 7K in 3rd blew a 94. After that I kept it at maintenance throttle around 6500 in 3rd until parallel to the booth and the rest of the day was fine.

Current system: I'm now running OEM sides with a JCR silenced CMB (with same Soul tips / track nanny) and had the exact same problem as the above setup except blew a 95 this time. I've come to the conclusion that the intake noise over 7K under full throttle is probably a culprit as well in all this.

I bought the car with a sharkwerks CMB which blew sound my first time there with OEM sides, track nanny and an SP Motorsports set of sweeps. In retrospect I'd probably just have stayed with the sharkwerks and the Soul tips if I knew then what I know now and saved some $. I do however like the JCR silenced CMB vs the Sharkwerks CMB for highway cruising as it's a fair amount quieter with the valves closed but still has great sound with valves open. (which I am not willing to give up just for LS)

But to answer your main question I think the track nanny is a must. In the real world side deletes are quite a bit louder with the valves open then one would think looking at the somewhat straight thru design of the OEM system. Without the nanny I think you'd need to be under 4K in 4th or 5th to even have a chance of getting by with side deletes. One of the side benefits to the Nanny is you can set it to loud and it keeps the valves open all the time for regular street use and other tracks vs pulling the vacumn lines and plugging.

Stephen Ayers

My 991.1 RS with the same config passes sound at Laguna.

ubtrippin

I've never understood why they limit personal cars but not the race cars

RDCR

HOD has a 103db day coming up in June so occasionally the track allows (and charges more for I've heard) higher sound limit days.

obbob

Laguna Seca is allowed by local government to have a certain number of high db days. Most of these days are allocated to professional events and racing. Then there are barely a handful of days left open, and they are sold (probably for higher price) to whoever wants them, usually HPDE clubs.

Ducati1199

Thanks everyone for the responses - sounds like there's a general consensus that the gps/nanny is a must. I'm of the same mindset that @RDCR is in that I'm not willing to run a total stock system just to get around LS once in a while when I can rip it up at Sonoma, Thunderhill and the street with no issues!! Appreciate the feedback guys.

porschemeister

what is the GPs solution? never heard of it, who makes it? I might have to get one reading all the comments for a 90db day

Hams955

Too bad you can't run full volume with side deletes and headers with your middle finger out the window.

Just saying.

skxf430

You can on unlimited days. There are a handful of unlimited sound days but usually a ton of cars show up.

RDCR

https://rennlist.com/forums/991-gt3-...ontroller.html

lisocayman

I can attest. 991.2 with GPS plus turns and you can go full throttle!

SmokinGTS

The Golden Gate region PCA has 4 days in late July that are all 103db. Wish I could be there.

Ducati1199

Is that with full OEM exhaust or with side muffler deletes? Thanks,