[HoldMyBeer]

Originally Posted by Rodan

You can't use stealth mode on track.

I thought you can go into settings and make the sound mode over ride other settings. for me, Ive only used a few times testing and all my other settings are active and it has stayed in 'stealth' even at full throttle.

Thought I'd ask.

[Rodan]

Sure you can override it into stealth. But there's a reason why the owner's manual explicitly states not to use stealth on track...



Not my car, BTW, but posted on this forum... that's what happens.

[HoldMyBeer]

Originally Posted by Rodan

Sure you can override it into stealth. But there's a reason why the owner's manual explicitly states not to use stealth on track...



Not my car, BTW, but posted on this forum... that's what happens.

Dang....gotcha, and glad I read this thread better than my handbook.

Thanks Rodan

[dlct3]

Originally Posted by Rodan

Looks good!

I'm very interested to hear the numbers on the stock muffler car.

I've been wondering if there's room for those resonators under the car somewhere? Something like the Borla 60608, but in 3"... Added to an otherwise stock exhaust, it might be enough to get under 95dB.

Me as well...I just need a little time and an extra hand to help test in that same location. Ideally I'd like a cool overcast day for comparable testing... I'll update once I do. I'd like to see sub 98 range so this would work for most any track.

[dlct3]

Updated pics with DEI titanium wrap, corsa extreme connection, 1 showing NPP when modifications were being made.

[dlct3]

Originally Posted by dlct3

Sorry for delay. However, we were finally able to modify and build a removable laguna pipe muffler system thats adjustable for any direction via the 2.5” vibrant vband. The whole setup is fairly lightweight at just under 8lbs. The fulcrum point is right next to an exhaust hanger for strength. We were able to achieve a lot lower DB level than expected especially on another fully built ZL1 with corsa extreme that we utilized Magnaflows 2.5” straight through 5” case. I wasn’t able to test at 50’ yet, but at idle the dB dropped approx 6db. On the highway under power I’m thinking the drop is just as much if not more than 10db.

Items used
Magnaflow Stainless 2.5” straight through design 14” long 4”case-ends cut down
2.5” 90 degree stainless mandrel with 12” leg and 3.5” medium radious
2.5” vibrant vband
1 extra vibrant Male vband for the stock tip
DEI titanium header wrap & stainless zip ties

I’ll update once I can head back to the same test location for an accurate DB check. However, I’m not concerned about being over 109 now.

*5” case used on the red ZLE as we had more room since we connected from the exit of the corsa muffler extreme system with headers, higher boost, no cats, and double x-pipe extreme system. That car’s idle lowered from 103 to 81.4 from 5’ away and 4,000 rpm revs very similar drop.

*disclaimer.. first time mig welding stainless and setting up the welder.. don’t criticize too hard.

UPDATE - 4-2-19
Tested at 45’ perpendicular with laguna set-up pointed 45degrees up and away from dB meter. 2 runs in 3rd gear. Upper rpm and almost max rpm under load going slightly uphil. Same test location. Sunny and clear conditions compared to cloudy on the before test. It sure what that is worth exactly.
98.3 & 99.0 dB compared to Avg. of 107 dB.

Overall approx 8 dB decadease and under my goal of 102 I’m happy.

[Rodan]

Originally Posted by dlct3

UPDATE - 4-2-19
Tested at 45’ perpendicular with laguna set-up pointed 45degrees up and away from dB meter. 2 runs in 3rd gear. Upper rpm and almost max rpm under load going slightly uphil. Same test location. Sunny and clear conditions compared to cloudy on the before test. It sure what that is worth exactly.
98.3 & 99.0 dB compared to Avg. of 107 dB.

Overall approx 8 dB decadease and under my goal of 102 I’m happy.

So is this the stock muffler car, or the Corsa Extreme car?

[dlct3]

Originally Posted by Rodan

So is this the stock muffler car, or the Corsa Extreme car?

Sorry, I should have clarified. This is the stock muffler NPP car with the magnaflow straight through design 4” round case that’s 14” long with a 2.5” core. I think based off the other cars idle it will be even a touch lower as that car was able to utilize a 5” case which showed twice the dB lowering effect vs this 4”.

[Rodan]

Thanks!

Our limit is 95dB and measured from both sides, so I'm probably SOL any way you look at it, but it's great data to have!

[GunMetalGrey]

I put 2 detachable 3" in and 3" out Flowmaster Super 50 series on my car (it does not have LT Headers yet) so I'd get under the 95 Db max sound level of my local track and I was way under!
79Db according to the tracks measurements.
The app I downloaded for my phone said 89-92Db
When listening by ear, it's barely louder at WOT than it is at idle/start up.

Who knows how accurate the App is and there is obviously a lot of variables and different ways to measure sound level. I think the main point is the Flow master Super 50 series are the largest mufflers I could find that would fit without having to be modified. I think they'd keep the car under 95db even with LT headers.

I don't recommend them for the street because they drone and don't go loud enough for my tastes, but that's personal preference.

[S.T.A.R.]

Originally Posted by datboi448

Move to one of the free states

[Rodan]

Originally Posted by GunMetalGrey

I put 2 detachable 3" in and 3" out Flowmaster Super 50 series on my car (it does not have LT Headers yet) so I'd get under the 95 Db max sound level of my local track and I was way under!

Did you replace the stock muffler, or are these in addition to?

Under what circumstances was the dB measurment taken? (gear, rpm, full throttle, distance, etc)

Please post some pictures.

[sujohn]

The porsche guys have figured out a pretty slick solution: https://speeddistrict.com/product/al...ve-controller/

GPS controlled exhaust valves - they stay open until the GPS tagged area (sound check booth) and then open back up again. This should be pretty easy for our cars, leave the car in stealth mode and only close the circuit where the car needs to be quiet.

Here is the thread where its discussed: https://rennlist.com/forums/991-gt3-...nd-checks.html

[viurniel]

Originally Posted by sujohn

The porsche guys have figured out a pretty slick solution: https://speeddistrict.com/product/al...ve-controller/

GPS controlled exhaust valves - they stay open until the GPS tagged area (sound check booth) and then open back up again. This should be pretty easy for our cars, leave the car in stealth mode and only close the circuit where the car needs to be quiet.

Here is the thread where its discussed: https://rennlist.com/forums/991-gt3-...nd-checks.html

That is fantastic and not hard to replicate.