Exhaust too loud

370z_stillen · 12-30-2021, 12:50 AM

Hello guys,

Currently my car is too loud, especially the drone in the inside. Recently changed my exhaust because my flow was too restrictive and I want to minimize loss of whp.

I have a supercharger, emptied cats for flow and a full Greddy evolution dual exhaust. The sound is deep and very little rasp which is good. But from the inside, the drone is too much.

What do you guys suggest:

1. Back to cats
2. Try to add an extra resonator/muffler
3. Change whole exhaust
4. ?

Update: The tuner has mentioned 30 or more whp loss if I go back to cats which is not my preference... so looking for other options. Thinking about adding some resonators in the y pipe which I hope will fit. Will contact a custom exhaust company for that.

BGTV8 · 12-30-2021, 02:31 PM

You can try inserting these under the car:
https://www.moroso.com/moroso-shop-browse/29000/2901/
These will drop 5-7DB of noise

OR you can try these:
https://spintechmufflers.com/mufflers-1/ but they will be a challenge to fit under the car because they take up a lot of real-estate.

I put a pair of 14" hot-dog resonators into the centre-section on my car and it knocked the edge off the reverb in the cabin at 2800-~3000rpm (110kph freeway speed).

spoolin03 · 12-30-2021, 03:15 PM

In for answers as well. My car is almost undriveable because the sound just eats away at me

redondoaveb · 12-30-2021, 03:24 PM

As far as drone, Motordyne Art pipes make a big difference.

spoolin03 · 12-30-2021, 03:29 PM

Quote:

Originally Posted by redondoaveb

As far as drone, Motordyne Art pipes make a big difference.

I thought they helped more with rasp? But if they take care of drone then I am interested... if I could find one that's not at rip-off prices

redondoaveb · 12-30-2021, 04:15 PM

Quote:

Originally Posted by spoolin03

I thought they helped more with rasp? But if they take care of drone then I am interested... if I could find one that's not at rip-off prices

They act the same as Helmholtz resonators which are used to reduce drone. They greatly reduced the drone on my Fast Intentions exhaust. They definitely help with rasp too, especially if you're coming from unresonated test pipes

redondoaveb · 12-30-2021, 04:20 PM

From Motordyne website

backman_66 · 12-30-2021, 04:25 PM

You can't have your cake and eat it.

1. You are supercharged. Should have went turbo if you wanted less sound.

2. You want max power so gutted your cats. There isn't really any good combination of exhausts that is going to reduce your noise levels enough to satisfy you. You're going to have to understand you'll have to eat some power in order to quieten things down through resonators and especially good mufflers.

DrBacon · 12-30-2021, 04:27 PM

As mentioned, definitely start with a resonated test pipe and go from there. There are other companies that make a knockoff motordyne test pipe that is similar and you don't have to wait 8+ months.

spoolin03 · 12-30-2021, 04:52 PM

Quote:

Originally Posted by redondoaveb

They act the same as Helmholtz resonators which are used to reduce drone. They greatly reduced the drone on my Fast Intentions exhaust. They definitely help with rasp too, especially if you're coming from unresonated test pipes

The 2.5" FI exhaust has drone? Oh no

I thought I could find some haven by purchasing an already made system but I guess drone will drone

spoolin03 · 12-30-2021, 04:52 PM

Quote:

Originally Posted by DrBacon

As mentioned, definitely start with a resonated test pipe and go from there. There are other companies that make a knockoff motordyne test pipe that is similar and you don't have to wait 8+ months.

Do you have links?

Spartan 1771 · 12-30-2021, 04:53 PM

If max power if your top priority, then anything you do at this point to lower the drone will decrease power.

As others have suggested, ART pipes should help. If they aren't enough, maybe consider a different CBE, such as a Fast Intentions with resonators. The combination of the resonators and ART pipes should definitely solve your issue.

spoolin03 · 12-30-2021, 04:54 PM

The FI 2.5" system seems like the best bet from what I've seen.

The design is very similar to OEM

The flow also seems to be reasonably good

Does this system drone even with the resonators?

spoolin03 · 12-30-2021, 04:56 PM

The Motordyne y-pipe is restrictive since the dual 2.5" pipes are forced to converge into 3" space twice

Spartan 1771 · 12-30-2021, 04:59 PM

Quote:

Originally Posted by spoolin03

The FI 2.5" system seems like the best bet from what I've seen.

The design is very similar to OEM

The flow also seems to be reasonably good

Does this system drone even with the resonators?

The design adds quite a bit of power over stock, but as far as drone is concerned with the resonators, I can't answer that. My FI set up doesn't have resonators. I wanted max power, regardless of drone. My Z isn't my daily driver.

12-30-2021, 12:50 AM	#1 (permalink)
370z_stillen Base Member Join Date: Oct 2021 Location: The Netherlands Posts: 26 Drives: 370z 40th SC Rep Power: 4	Exhaust too loud Hello guys, Currently my car is too loud, especially the drone in the inside. Recently changed my exhaust because my flow was too restrictive and I want to minimize loss of whp. I have a supercharger, emptied cats for flow and a full Greddy evolution dual exhaust. The sound is deep and very little rasp which is good. But from the inside, the drone is too much. What do you guys suggest: 1. Back to cats 2. Try to add an extra resonator/muffler 3. Change whole exhaust 4. ? Update: The tuner has mentioned 30 or more whp loss if I go back to cats which is not my preference... so looking for other options. Thinking about adding some resonators in the y pipe which I hope will fit. Will contact a custom exhaust company for that. Last edited by 370z_stillen; 12-30-2021 at 11:59 AM.

12-30-2021, 03:24 PM	#4 (permalink)
redondoaveb A True Z Fanatic Join Date: Apr 2017 Location: So. Commiefornia Posts: 6,370 Drives: 2014 Nismo Gunmetal Rep Power: 2684374	As far as drone, Motordyne Art pipes make a big difference. Spartan 1771 and Falconquey like this. __________________ Fast Intentions "Stage Seb" twin turbo #098- Specialty Z/Tial-Xonarotor/CJM/Ecutek/HKS/KW/SPL/Hotchkis/Rohana/Toyo 700+whp

12-30-2021, 04:25 PM	#8 (permalink)
backman_66 Base Member Join Date: Nov 2019 Location: US Posts: 64 Drives: 2012 G37 Rep Power: 6	You can't have your cake and eat it. 1. You are supercharged. Should have went turbo if you wanted less sound. 2. You want max power so gutted your cats. There isn't really any good combination of exhausts that is going to reduce your noise levels enough to satisfy you. You're going to have to understand you'll have to eat some power in order to quieten things down through resonators and especially good mufflers. Optimiser, wanker and Rjk370z like this.

12-30-2021, 04:53 PM	#12 (permalink)
Spartan 1771 A True Z Fanatic Join Date: Nov 2009 Location: Western Maryland Posts: 1,280 Drives: Wife crazy & 09 370Z Rep Power: 105454	If max power if your top priority, then anything you do at this point to lower the drone will decrease power. As others have suggested, ART pipes should help. If they aren't enough, maybe consider a different CBE, such as a Fast Intentions with resonators. The combination of the resonators and ART pipes should definitely solve your issue. __________________ ~Rob -DD Air Guide, Stillen G3 CAIs, 63mm Throttle Bodies, Motordyne M370, Berk HFCs, FI TDX CBE (non-res, CF), Sprint booster v3, Ecutek Dyno Tuned, and the list goes on...

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12-30-2021, 02:31 PM	#2 (permalink)
BGTV8 A True Z Fanatic Join Date: Dec 2009 Location: 03350 Australia Posts: 1,515 Drives: 09 Nissan 370Z M6 Rep Power: 39974	You can try inserting these under the car: https://www.moroso.com/moroso-shop-browse/29000/2901/ These will drop 5-7DB of noise OR you can try these: https://spintechmufflers.com/mufflers-1/ but they will be a challenge to fit under the car because they take up a lot of real-estate. I put a pair of 14" hot-dog resonators into the centre-section on my car and it knocked the edge off the reverb in the cabin at 2800-~3000rpm (110kph freeway speed).

12-30-2021, 03:15 PM	#3 (permalink)
spoolin03 Base Member Join Date: Jul 2021 Location: . Posts: 52 Drives: . Rep Power: 6714	In for answers as well. My car is almost undriveable because the sound just eats away at me

12-30-2021, 04:27 PM	#9 (permalink)
DrBacon Enthusiast Member Join Date: Nov 2016 Location: Washington Posts: 285 Drives: 2014 Nismo Rep Power: 27365	As mentioned, definitely start with a resonated test pipe and go from there. There are other companies that make a knockoff motordyne test pipe that is similar and you don't have to wait 8+ months.

12-30-2021, 04:54 PM	#13 (permalink)
spoolin03 Base Member Join Date: Jul 2021 Location: . Posts: 52 Drives: . Rep Power: 6714	The FI 2.5" system seems like the best bet from what I've seen. The design is very similar to OEM The flow also seems to be reasonably good Does this system drone even with the resonators?

12-30-2021, 04:56 PM	#14 (permalink)
spoolin03 Base Member Join Date: Jul 2021 Location: . Posts: 52 Drives: . Rep Power: 6714	The Motordyne y-pipe is restrictive since the dual 2.5" pipes are forced to converge into 3" space twice