I know that the 991 GT3 is having some problems getting under the db noise level at some tracks, but how is the noise level for the GT4? Any experience with drive-by noise level, compared to the 991 GT3?

Thanks JB

 

I got meatballed at Laguna with a 96 db when I "forgot" about sound requirements and floored it out of T5 with the loud button set to on.

 

Valves automatically open at WOT regardless of the button from what everyone tells me, no?

 

Very possible. I don't know for sure.

 

Watching this video, it sounds like even at high revs and (I assume) WOT, there's a difference. Maybe not enough to matter for a given track's noise limits, but I think PSE does more than just keeping the car quiet at low rev ranges and suppressing the overrun burble:

 

As others stated, the button doesn't matter at those RPMs. From what I'm told, a stock CS with PSE won't pass sound at Laguna without an redirect on the tips, so I can't imagine the GT4 could.

 

This do?

 

Does anyone know the actual DB is inside the car at WOT? I think I saw a video review of the gt4 and it said 125 db right at the back of the rear bumper.

 

Did you have that custom made?

Any idea how much lower the db's are with it on?

 

Not mine unfortunately. The exhaust was a custom arrangement by Mike Edwards Motorsport near London.

The owner tells me it reduced UK track static test (75% max revs tested at 45 degrees from exhaust outlet at 1 metre distance) to 92db from I guess 101/102db.

I run a 3.8L PDK Cayman with 200 cell headers (normally 101db static) and have found turndown tips helpful in reducing drive by noise as heard by detectors.

 

Considering a track day at Laguna Seca next month (have to decide quickly) and the sound requirements are always a pain. But it's a bucket list item to drive on that track.

Does anyone know how easy/hard it is to meet sound if you lift while passing the sound station? Seems like it might not be reliable.

 

Everything I've read on Rennlist indicates that none of the Porsches with PSE will pass Laguna without some kind of exhaust redirect or manual PSE value closure. I'm guessing lifting going up the hill is liable to get you asspacked by another driver.

 

In Australia that's the test and new cars are meant to be under 92db. I had been wondering how it managed to pass the regs here and now I understand, it doesn't

 

Yes I was thinking about that too. Just not safe to lift unless everyone is on the same page.

 

It's not a major lift, it's a go to maintenance throttle lift. Most newer sports cars have to do this given the requirements. Everyone's usually really aware of the sound booth and since most track days are not races, it works out mostly.