Tips for lowering dB? (Tomei expreme Ti)

Laomatik · 11-13-2017, 11:10 AM

Does anyone have tips on how to quiet this exhaust down? NCM has a 103dB limit at 50 feet and I doubt installing the silencer do much to help meet this level especially since the installation of test pipes.

Are there any products (baffles, turn downs) that can be easily adapted to the exhaust? Or will a custom solution be needed so I can run at NCM?

Thanks in advance for any advice.

echoshotz · 11-13-2017, 11:34 AM

probably going to need to do something custom. This is the reason I got rid of my Tomei. they did however just come out with a v2 silencer you can find on Z1's site that *may* work. But the tomei is just so loud I doubt it

Laomatik · 11-13-2017, 01:44 PM

Quote:

Originally Posted by echoshotz

probably going to need to do something custom. This is the reason I got rid of my Tomei. they did however just come out with a v2 silencer you can find on Z1's site that *may* work. But the tomei is just so loud I doubt it

Thanks for the heads up, I wasn't aware of the v2 silencer. Maybe if I have a turn down added to it as well as some baffles on the inside I can reach my dB goal... I refuse to give up my Tomei lol.

BGTV8 · 11-13-2017, 01:49 PM

There is a product called a spiral silencer which I use on my race car. I don't have a US reference but you might want to check Spintech Mufflers who are US based. Google should help out

Rusty · 11-13-2017, 10:19 PM

If you know what side of car the meter will be on. You can add turn downs that point away from that side. I've seen guys do that.

Laomatik · 11-15-2017, 07:21 AM

Quote:

Originally Posted by Rusty

If you know what side of car the meter will be on. You can add turn downs that point away from that side. I've seen guys do that.

Left side coming out of turn 2b onto a straight... I've thought about a turndown to the ground but maybe pointing it away from them will work better?

Laomatik · 11-15-2017, 07:19 AM

Quote:

Originally Posted by BGTV8

There is a product called a spiral silencer which I use on my race car. I don't have a US reference but you might want to check Spintech Mufflers who are US based. Google should help out

Is that for a full muffler? I was hoping for something to add to my silencer and be able to take on and off.

BGTV8 · 11-22-2017, 03:57 PM

Quote:

Originally Posted by Laomatik

Is that for a full muffler? I was hoping for something to add to my silencer and be able to take on and off.

These are 15" long "hot-dog" style silencers.

My race car (5-litre V8, 14.2:1 on E85) runs 1.75" primaries into 3" collector into one of these mufflers (3" in and out) each side of the car and that is the ONLY muffler on the car and it is 93 Dba on 30metre drive-by test.

I have a pair of these on each side of my 370Z (one under the seats and the other at the rear) with motorsport cats (100cpi) and it passes the 75Dba drive-by on the track but still sounds "fat".

If you want your car to be "loud" on the street and you are being forced to be "quiet" on the track, the 65 y.o. in me thinks you might be a bit anti-social, but that's just an aside.

Laomatik · 11-29-2017, 11:04 AM

Quote:

Originally Posted by BGTV8

These are 15" long "hot-dog" style silencers.

My race car (5-litre V8, 14.2:1 on E85) runs 1.75" primaries into 3" collector into one of these mufflers (3" in and out) each side of the car and that is the ONLY muffler on the car and it is 93 Dba on 30metre drive-by test.

I have a pair of these on each side of my 370Z (one under the seats and the other at the rear) with motorsport cats (100cpi) and it passes the 75Dba drive-by on the track but still sounds "fat".

If you want your car to be "loud" on the street and you are being forced to be "quiet" on the track, the 65 y.o. in me thinks you might be a bit anti-social, but that's just an aside.

It can be loud at some tracks. I was just looking at ways to get to other tracks that have a dB limit. I'm gonna see if some baffles in the silencer and a turn down will be enough

Brendan · 11-14-2017, 05:58 PM

found a promo video for the tomei silencer

https://www.youtube.com/watch?v=emHA...ature=youtu.be

the last one sounds about as loud as a cat fart. may be your best option.

Rusty · 11-14-2017, 06:21 PM

Quote:

Originally Posted by Brendan

found a promo video for the tomei silencer

https://www.youtube.com/watch?v=emHA...ature=youtu.be

the last one sounds about as loud as a cat fart. may be your best option.

This comes to mind.

gomer_110 · 11-14-2017, 07:06 PM

While I can't give you a link to one, I've seen inserts that go in the end of the muffler that are designed to reduce the sound.

Also the turndown idea works pretty well. Even just pointing the turn down at the ground can make a big difference. Not sure the diameter of the tomei muffler tip but I've commonly seen autoxers use a HVAC duct elbow as a turn down with just a hose clamp holding it on.

Laomatik · 11-15-2017, 07:23 AM

Quote:

Originally Posted by gomer_110

While I can't give you a link to one, I've seen inserts that go in the end of the muffler that are designed to reduce the sound.

Also the turndown idea works pretty well. Even just pointing the turn down at the ground can make a big difference. Not sure the diameter of the tomei muffler tip but I've commonly seen autoxers use a HVAC duct elbow as a turn down with just a hose clamp holding it on.

Will the HVAC duct hold its shape at track speeds?

gomer_110 · 11-15-2017, 07:53 AM

Quote:

Originally Posted by Laomatik

Will the HVAC duct hold its shape at track speeds?

It's only an elbow piece I'm talking about so I would think so. I know they do just fine at speeds approaching 90 mph. No knowledge beyond that but I wouldn't see any reason they would deform.

Laomatik · 11-15-2017, 09:02 AM

Quote:

Originally Posted by gomer_110

It's only an elbow piece I'm talking about so I would think so. I know they do just fine at speeds approaching 90 mph. No knowledge beyond that but I wouldn't see any reason they would deform.

Something like this?

https://www.amazon.com/Duct-Elbow-De.../dp/B00BLUA5Z8

I think that could actually work. I just hope it's enough. Does anyone know of any cheap decibel meters I can use to test?

11-13-2017, 11:10 AM	#1 (permalink)
Laomatik Base Member Join Date: Dec 2015 Location: Smyrna, TN Posts: 115 Drives: 12 Nissan 370Z MB M6 Rep Power: 10	Tips for lowering dB? (Tomei expreme Ti) Does anyone have tips on how to quiet this exhaust down? NCM has a 103dB limit at 50 feet and I doubt installing the silencer do much to help meet this level especially since the installation of test pipes. Are there any products (baffles, turn downs) that can be easily adapted to the exhaust? Or will a custom solution be needed so I can run at NCM? Thanks in advance for any advice.

11-13-2017, 11:34 AM	#2 (permalink)
echoshotz Base Member Join Date: May 2015 Location: Knoxville, TN Posts: 218 Drives: 14 Nismo Rep Power: 73	probably going to need to do something custom. This is the reason I got rid of my Tomei. they did however just come out with a v2 silencer you can find on Z1's site that may work. But the tomei is just so loud I doubt it Brendan likes this. __________________ 2014 Solid Red Nismo 370z Motordyne\|Synergy Composites\|Stance Suspension\|Recaro\|RJM\|EVOR

11-13-2017, 10:19 PM	#5 (permalink)
Rusty Ronin Samurai - Assassin Join Date: Dec 2011 Location: Fayettenam,Pennsyltucky Age: 69 Posts: 35,383 Drives: 2011 Nismo GM 6M Rep Power: 2684438	If you know what side of car the meter will be on. You can add turn downs that point away from that side. I've seen guys do that. gomer_110, danegrey and Elmo370z like this. __________________ 浪人 - 殺し屋 "The Difficult Anytime, The Impossible By Appointment Only" http://www.the370z.com/members-370z-...o-journal.html

11-14-2017, 05:58 PM	#10 (permalink)
Brendan Track Member Join Date: Apr 2013 Location: Colorado Posts: 646 Drives: Poor man's Porsche Rep Power: 543	found a promo video for the tomei silencer https://www.youtube.com/watch?v=emHA...ature=youtu.be the last one sounds about as loud as a cat fart. may be your best option. Zbrah likes this.

11-14-2017, 07:06 PM	#12 (permalink)
gomer_110 A True Z Fanatic Join Date: Aug 2011 Location: Perrysburg, OH Posts: 17,992 Drives: '11 Nismo #528 GM Rep Power: 36941	While I can't give you a link to one, I've seen inserts that go in the end of the muffler that are designed to reduce the sound. Also the turndown idea works pretty well. Even just pointing the turn down at the ground can make a big difference. Not sure the diameter of the tomei muffler tip but I've commonly seen autoxers use a HVAC duct elbow as a turn down with just a hose clamp holding it on. __________________ '11 370Z Nismo #528 Fast Intentions \| Stillen \| Motordyne \| Uprev \| CSF \| Zspeed \| Z1 Motorsports \| AST \| Swift \| SPC \| SPL \| Whiteline \| Hotchkis \| Bride \| Schroth \| Robispec \| Cusco \| Nismo \| Volk \| Forgestar \| Hoosier \| RJM '17 Titan Bone Stock

11-13-2017, 01:49 PM	#4 (permalink)
BGTV8 A True Z Fanatic Join Date: Dec 2009 Location: 03350 Australia Posts: 1,515 Drives: 09 Nissan 370Z M6 Rep Power: 39974	There is a product called a spiral silencer which I use on my race car. I don't have a US reference but you might want to check Spintech Mufflers who are US based. Google should help out

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