HFC + Nismo Rasp/Tin Can

conquistador · 12-13-2014, 08:16 PM

This isn't me but my exhaust sounds similar. It sounds like something is loose or vibrating, maybe even an exhaust leak but I checked everything. If the rasp was gone, the exhaust would sound perfect, imo. Weird thing is once the engine is at operating speed, a lot of the rasp is gone.

Options? Vibrant resonators, ART pipes, custom helmholtz, specific catback?

Foxlogik · 12-28-2014, 05:51 PM

There's pretty much no way around it, just exhaust physics at work.

You're allowing upwards of 50% more flow to a resonator and muffler not designed for that much exhaust. If you read up on how gasses like to flow, bent tubes vs. mandrel bent tubes, and really any custom exhaust forums you'll get a good idea on how unhappy exhaust can get(raspy).

I designed a custom exhaust for some Volkswagen R32's (THE raspiest engine on the planet) and it takes a lot of fiddling and matching to lower the rasp.

But no worries, I've got Berk HFC's on my stock Z exhaust and it's raspy. just the nature of the game.

The only way around it is to get an aftermarket catback setup (not NISMO), or just larger exhaust tubes.

Chuck33079 · 12-28-2014, 06:04 PM

The hiss on decel is unavoidable. It's just one of the sounds the motor makes.

Merv · 12-28-2014, 09:44 PM

I had a heat shield come loose on me and sound similar to that on another car. I would double check underneath for anything loose. But wow,I thought I heard rasp before... Didn't think switching out a component on a stock exhaust would make it sound like that!

conquistador · 12-30-2014, 11:49 PM

Turns out it was a heat shield and some pebbles stuck in between right above where the mid pipe and y pipe meet

Merv · 12-31-2014, 11:28 AM

Right on man. How she sound now? Hopefully no where near what that video sounds like!

12-13-2014, 08:16 PM	#1 (permalink)
conquistador Base Member Join Date: Sep 2014 Location: CA Posts: 46 Drives: G37 Sedan Rep Power: 11	HFC + Nismo Rasp/Tin Can This isn't me but my exhaust sounds similar. It sounds like something is loose or vibrating, maybe even an exhaust leak but I checked everything. If the rasp was gone, the exhaust would sound perfect, imo. Weird thing is once the engine is at operating speed, a lot of the rasp is gone. Options? Vibrant resonators, ART pipes, custom helmholtz, specific catback?

12-28-2014, 06:04 PM	#3 (permalink)
Chuck33079 A True Z Fanatic Join Date: Nov 2011 Location: Houston Posts: 12,265 Drives: 2011 370ztt Rep Power: 29539	The hiss on decel is unavoidable. It's just one of the sounds the motor makes. __________________ 2011 MB Touring-Sport-6sp-Nav/GTM TT/FI TT TDX/JTran/Kosmic/Eibach/Hotchkis/SPC/CSF/RPS/SoThatsWhereAllMyMoneyWent

12-28-2014, 09:44 PM	#4 (permalink)
Merv Track Member Join Date: Dec 2013 Location: Vancouver B.C Posts: 518 Drives: 11 GM grey sport tou Rep Power: 15	I had a heat shield come loose on me and sound similar to that on another car. I would double check underneath for anything loose. But wow,I thought I heard rasp before... Didn't think switching out a component on a stock exhaust would make it sound like that! __________________ Swift springs \| upgraded headlights \| stillen gen3 cai \| FI HFC's and FI CBE \| ecutek tune in the mail!

12-31-2014, 11:28 AM	#6 (permalink)
Merv Track Member Join Date: Dec 2013 Location: Vancouver B.C Posts: 518 Drives: 11 GM grey sport tou Rep Power: 15	Right on man. How she sound now? Hopefully no where near what that video sounds like! __________________ Swift springs \| upgraded headlights \| stillen gen3 cai \| FI HFC's and FI CBE \| ecutek tune in the mail!

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12-28-2014, 05:51 PM	#2 (permalink)
Foxlogik Base Member Join Date: Jun 2013 Location: Houston, TX Posts: 9 Drives: black '09 370z Rep Power: 12	There's pretty much no way around it, just exhaust physics at work. You're allowing upwards of 50% more flow to a resonator and muffler not designed for that much exhaust. If you read up on how gasses like to flow, bent tubes vs. mandrel bent tubes, and really any custom exhaust forums you'll get a good idea on how unhappy exhaust can get(raspy). I designed a custom exhaust for some Volkswagen R32's (THE raspiest engine on the planet) and it takes a lot of fiddling and matching to lower the rasp. But no worries, I've got Berk HFC's on my stock Z exhaust and it's raspy. just the nature of the game. The only way around it is to get an aftermarket catback setup (not NISMO), or just larger exhaust tubes.

12-30-2014, 11:49 PM	#5 (permalink)
conquistador Base Member Join Date: Sep 2014 Location: CA Posts: 46 Drives: G37 Sedan Rep Power: 11	Turns out it was a heat shield and some pebbles stuck in between right above where the mid pipe and y pipe meet