Raspy exhaust

Adampau123 · 03-18-2019, 09:31 PM

So just did the primary cat deletes verses full longtube headers because of ease of install plus don’t like the sound of headers on the NPP exhaust. Love the sound without load when just free revving the engine, however when driving the exhaust is very raspy at times and just doesn’t seem to sound right. Any suggestions on what to do. Really want to keep stock NPP even though it rattles and dealer can’t seem to fix it... maybe this is part of my issue?

pyroguy · 03-19-2019, 08:41 AM

Eliminating cats will add rasp to an exhaust. If you'd eliminated all of the cats then you'd have a very raspy exhaust sound. It's just nature of the beast.

Umbriel · 03-19-2019, 09:03 AM

Quote:

Originally Posted by pyroguy

Eliminating cats will add rasp to an exhaust. If you'd eliminated all of the cats then you'd have a very raspy exhaust sound. It's just nature of the beast.

Agree, I am running headers with no cats into an AWE Touring catback with resonators and it still gets raspy at certain rpms. I bought the resonated version to help with that but with no cats there really isn't much you can do unfortunately. Everyone absolutely loves the way my exhaust sounds though.

avalonandl · 03-19-2019, 09:39 AM

Adding an Hpipe/resonator is the only way to remove raspiness if keeping OEM NPP.

Myslef I am keeping OEM manifolds and cats for this reason

Jhunsberger · 03-19-2019, 09:46 AM

I did full cat deletes thru otherwise stock exhaust. Hated the sound, but got rid of the cats for the Whipple. Then did full cat back Borla atak with their resonator in the mid-pipe. This helped and made it more tolerable, although still raspy. Just recently ditched the cat delete pipes, and went to 2" kooks headers, no cats still, seems a little less raspy.

Point is removing the cats make it raspy.

JonD · 03-19-2019, 11:13 AM

Only system that’s catless & raspless, that I’ve Heard is ARH’s Full system
It’s clean as hell

lDejavul · 03-19-2019, 12:52 PM

I had the same issue. I went and had an H pipe put in. Didn't completely fix it but it does sound better.

Mark114 · 03-19-2019, 01:04 PM

Some people have installed the Borla resonator to tone down a cat delete. There are numerous threads with details if you are interested.

https://www.borla.com/products/camar...rt__60608.html

Adampau123 · 03-19-2019, 04:35 PM

Hmmm how much does that Borla resonator tone it down? Trying to find videos

cmitchell17 · 03-19-2019, 06:07 PM

How would everyone compare the corvette NPP to the camaro one, in terms of rasp, I think the corvette NPP sounds so much better because it dosent rasp like the camaro NPP.

Whocares05050 · 03-19-2019, 07:19 PM

Quote:

Originally Posted by cmitchell17

How would everyone compare the corvette NPP to the camaro one, in terms of rasp, I think the corvette NPP sounds so much better because it dosent rasp like the camaro NPP.

The corvette NPP has glass packing and the camaro does not.

Whocares05050 · 03-19-2019, 07:20 PM

OP, weld a few of these in and should solve most of your rasp issues.

https://www.amazon.com/Vibrant-1792-.../dp/B000E3VHVO

Jhunsberger · 03-20-2019, 05:11 AM

Quote:

Originally Posted by Adampau123

Hmmm how much does that Borla resonator tone it down? Trying to find videos

This is stock manifolds, full cat delete, borla resonator, borla atak cat back (sport or track mode):

(This should work, there should be 4 video clips to scroll thru)

https://www.amazon.com/photos/shared...UQYR0QIJ5QqbLQ

meilmarc · 03-20-2019, 02:54 PM

Im running a borla stype axelback with a custom Hpipe, and catless longtubes, most of the rasp is gone.

03-18-2019, 09:31 PM	#1
Adampau123 Drives: 2017 Red Hot 1SS 1LE Join Date: Aug 2016 Location: Orlando Florida Posts: 187	Raspy exhaust So just did the primary cat deletes verses full longtube headers because of ease of install plus don’t like the sound of headers on the NPP exhaust. Love the sound without load when just free revving the engine, however when driving the exhaust is very raspy at times and just doesn’t seem to sound right. Any suggestions on what to do. Really want to keep stock NPP even though it rattles and dealer can’t seem to fix it... maybe this is part of my issue?

03-19-2019, 08:41 AM	#2
pyroguy Started#gottalovethatblue Drives: ABM #831 Join Date: Apr 2013 Location: TN Posts: 6,917 View My Garage	Eliminating cats will add rasp to an exhaust. If you'd eliminated all of the cats then you'd have a very raspy exhaust sound. It's just nature of the beast. __________________ '10 Camaro 2SS/RS \| Aqua Blue #831 of 3,903 \| Silver Stripes Check out my build thread

03-19-2019, 09:39 AM	#4
avalonandl Drives: 2019 ZL-1 Join Date: Feb 2009 Location: Troy, MI & Naples, FL Posts: 2,019	Adding an Hpipe/resonator is the only way to remove raspiness if keeping OEM NPP. Myslef I am keeping OEM manifolds and cats for this reason __________________ 2019 ZL-1 Acquired 4/23/21 at 6300 miles. Riverside Blue, A10, PDR. Traded in 2017 2SS with 6M and 32k miles. Continental Extreme Contact Sports. Now has 10,000 miles... 2012 Yukon XL Denali w/ 6.2 AWD

03-19-2019, 09:46 AM	#5
Jhunsberger Drives: 2017 Camaro 1SS M6 (SOLD) Join Date: Oct 2016 Location: 19518 Posts: 402	I did full cat deletes thru otherwise stock exhaust. Hated the sound, but got rid of the cats for the Whipple. Then did full cat back Borla atak with their resonator in the mid-pipe. This helped and made it more tolerable, although still raspy. Just recently ditched the cat delete pipes, and went to 2" kooks headers, no cats still, seems a little less raspy. Point is removing the cats make it raspy. __________________ 2017 1SS M6 Hyper Blue Metallic NPP, MMR 228 Z/28 replica wheels, Front: 20 x 9, Rear 20 x 11 Stock: 416hp/427tq, 12.21 @ 116.80 Modified 02/2019: Whipple SC w/ 3.500 pulley, LT4 fueling, NW 103 TB, Roto-Fab Big Gulp, Kooks 2" jet coated, full Borla ATAK exhaust, DSS axles, Gforce driveshaft. Tuned by EFX Tuning 688hp/632tq Best 1/4 to date: 10.705 @ 131.92

03-19-2019, 11:13 AM	#6
JonD Drives: 2018 SS 1LE Join Date: May 2018 Location: Arizona Posts: 292	Only system that’s catless & raspless, that I’ve Heard is ARH’s Full system It’s clean as hell __________________ 🌽 Sauced, 2018 SS 1LE - 123mph @ 5,000 DA ARH 2”x3” FULL System, Pray Ported MSD Intake Manifold, Pray Ported GM 95mm TB, RotoFab CAI, DsX e85 Kit, MightyMouse Catch Can, NicD Tune https://instagram.com/corn_sauced?ut...d=o0ako89uurwl

03-19-2019, 12:52 PM	#7
lDejavul Drives: Camaro SS Join Date: Sep 2015 Location: Oklahoma Posts: 621 View My Garage	I had the same issue. I went and had an H pipe put in. Didn't completely fix it but it does sound better. __________________ Adrenaline Red 20" 5 Spoke Black Black Side Spear Dual Mode Exhaust MRC Splash Guards 1G1FG1R74G0124089

03-19-2019, 01:04 PM	#8
Mark114 Drives: 2016 2SS Convertible Join Date: May 2012 Location: St. Louis, MO Posts: 1,710 View My Garage	Some people have installed the Borla resonator to tone down a cat delete. There are numerous threads with details if you are interested. https://www.borla.com/products/camar...rt__60608.html

03-19-2019, 04:35 PM	#9
Adampau123 Drives: 2017 Red Hot 1SS 1LE Join Date: Aug 2016 Location: Orlando Florida Posts: 187	Hmmm how much does that Borla resonator tone it down? Trying to find videos

03-19-2019, 06:07 PM	#10
cmitchell17 Drives: 17 2SS, 8L90, Cam, Heads, E85 Join Date: Dec 2016 Location: US Posts: 1,201	How would everyone compare the corvette NPP to the camaro one, in terms of rasp, I think the corvette NPP sounds so much better because it dosent rasp like the camaro NPP.

03-19-2019, 07:20 PM	#12
Whocares05050 Drives: 2018 Camaro SS 1LE Join Date: Oct 2018 Location: Treasure Coast, FL Posts: 384	OP, weld a few of these in and should solve most of your rasp issues. https://www.amazon.com/Vibrant-1792-.../dp/B000E3VHVO

03-20-2019, 02:54 PM	#14
meilmarc Drives: 2016 2SS, HBM, NPP, Sun Roof Join Date: Jun 2013 Location: Houston, Tx Posts: 87	Im running a borla stype axelback with a custom Hpipe, and catless longtubes, most of the rasp is gone.

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