ARK DT-S exhaust sound db measurement

Gerrit 370Z

A few years ago I bought a used stock 2010 370Z, automatic transmission, currently 87,000 miles. In April 2021 I had an ARK DT-S exhaust installed and had an Uprev flash and tune done. After the tune the maximum Dynojet WHP was 303hp and 256 torque, a 10% increase, which increased power I can definitely notice on the street. The ARK DT-S exhaust sounds great but was too loud. Driving with the windows closed and going WOT to 6000rpm hurt my ears, not fun and distracting from the driving experience. To measure the dB I downloaded several dB meter apps on my Samsung S10+ cell phone, but 78dB was the maximum it was able to measure. My cell phone microphone cannot measure dB accurately.

So I bought a dedicated dB meter. I made sound dB measurements 20” from the exhaust tip (see pic). Cold start 103dB, 30” later drops to 90dB. Inside 370Z with windows closed driving WOT to 6000rpm is 99 dB, which is annoyingly loud!

Five months and 1400 miles later I did see carbon buildup in the exhaust and I repeated the measurements. Cold start 99dB, 30” later drops to 85dB. Inside 370Z with windows closed driving WOT to 6000rpm is 98dB. So it is true, over time the exhaust does get a few dB quieter, but is still quite loud.

I live in California, drive my red 370Z by a police station everyday, and I really don’t want to get pulled over for a loud exhaust fix it ticket. I wanted to quiet the exhaust more and I installed the Skunk2 MegaPower exhaust silencer. I had to cut 2” of one silencer to make it fit in the right ARK DT-S exhaust pipe. The ARK DT-S pipe OD is 2.5” and the ID is 2.375”. The silencer ID is only 1 5/8”, so I drilled five 0.5” holes to increase the total silencer exhaust area to the equivalent of 2” ID (see pic), which is large enough since the engine never stays long at 6000rpm (I rarely rev to 7500 rpm). Had to drill holes in the beautiful ARK tips to mount the silencers. dB results: Cold start 97dB, 30” later drops to 83dB. Inside 370Z with windows closed driving WOT to 6000rpm is 96 dB. So with the silencers about a 3dB drop compared to a newly installed exhaust. 3dB isn’t much but it somehow definitely sounds much more quiet and the ARK DT-S still has a good deep exhaust sound. Now I’m not afraid to go WOT to 6000rpm and very much enjoy driving my 370Z. Slight power loss but no check engine SES light issues. It’s a compromise.

Attached Images

	ARK DT-S 1.jpg (107.6 KB, 14 views)
	ARK DT-S 2.jpg (127.3 KB, 11 views)
	ARK DT-S 3.jpg (265.2 KB, 10 views)

Cyber370

I feel your pain. I had the Ark DTS and removed it a couple of months ago. I could no longer deal with the drone in the 3.5-4k rpm range and it was extremely loud at WOT. I went back to OEM H-pipe and mid pipe with an AAM S-line muffler. It is now perfect. At least I can now rev the crap out of it without my ears bleeding. I managed to sell the ARk exhaust but I took a massive loss. Oh well, live and learn. What is quiet to some is painfully loud to others.

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"That’s when you know you’ve found somebody special. When you can just shut the f*ck up for a minute and comfortably enjoy the silence.”-Mia (Pulp Fiction)

axmea?

Enjoy your exhaust. If you get stopped for exceeding "the limit" do not admit "it was loud". Ask the officer in a nice way, how he or she was able to determine how loud it was and how they determined your exhaust exceeded the limit and note it down. Again, never admit you went past the limit. Getting a db meter only verifies what you already know. It does not help you if you get stopped. I've beaten CA motor vehicle code 27150 and 27151. Also, 99% of officers who stop you will ask you to pop the hood to check for mods so if you have an intake, make sure you have a CARB sticker on it. Stillen and Takeda has CARB certification. A CARB sticker on anything helps, even if not related to your exhaust. I used it as part of my argument. Oh, they will try too get your car to a CA referee. F that, and schedule to go to court instead. A referee is the last thing you ever want to do.

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