Npp vs corsa
Thread Starter
Instructor
Joined: Apr 2014
Posts: 168
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From: Tracy Ca
Npp vs corsa
So I'm in kind of a dilemma.
I am installing my cam and longtubes next week. I have Corsa sport axle back mufflers right now. But the town I live in is really bad with cops and people getting pulled over for modified cars and the last thing I need is to get reffed.
I have a buddy that has some NPP mufflers he said I can have and I know with the valves closed it will help a LOT with the noise.
But I LOVE the way the corsa's sound. So I'm kind of at a toss up of what to do.
Any input? Thanks
I am installing my cam and longtubes next week. I have Corsa sport axle back mufflers right now. But the town I live in is really bad with cops and people getting pulled over for modified cars and the last thing I need is to get reffed.
I have a buddy that has some NPP mufflers he said I can have and I know with the valves closed it will help a LOT with the noise.
But I LOVE the way the corsa's sound. So I'm kind of at a toss up of what to do.
Any input? Thanks
Thread Starter
Instructor
Joined: Apr 2014
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From: Tracy Ca
Racer
Joined: Jan 2014
Posts: 400
Likes: 37
From: Lone Star State
I have a cam and long tubes with the NPP exhaust, car is loud *** hell on cold start for about 1 second until the exhaust closes, after that it's noticeable that the car is camed, but it's reasonably loud. It does not draw attention from the law, but when my cam kicks in about 3500 rpm same as the exhaust opening it is crazy f-cking loud. You can always install a switch with the NPP exhaust and open it when you want it, or just leaving it open at the track, this is what I do.
Thread Starter
Instructor
Joined: Apr 2014
Posts: 168
Likes: 0
From: Tracy Ca
I have a cam and long tubes with the NPP exhaust, car is loud *** hell on cold start for about 1 second until the exhaust closes, after that it's noticeable that the car is camed, but it's reasonably loud. It does not draw attention from the law, but when my cam kicks in about 3500 rpm same as the exhaust opening it is crazy f-cking loud. You can always install a switch with the NPP exhaust and open it when you want it, or just leaving it open at the track, this is what I do.
Racer
Joined: Jan 2014
Posts: 400
Likes: 37
From: Lone Star State
I made my own switch, it's easy, when the fuse is pulled the exhaust is open, so I made a switch that opens the fuse when I want it loud.
Also there is no drown with the NPP when closed, crazy quite. If you want to hear the exhaust with the stereo loud windows up AC blowing, you just open the loud switch, you can hear your throttle input.
Also there is no drown with the NPP when closed, crazy quite. If you want to hear the exhaust with the stereo loud windows up AC blowing, you just open the loud switch, you can hear your throttle input.
Race Director
Joined: Aug 2005
Posts: 13,592
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From: Hudson WI
NCM Sinkhole Donor
I just helped a friend that had a code and an idle issue. When you run the vacuum line to the back of the car, make sure you have good connections and that the vacuum tank in good or you will have an issue with vacuum leaks.
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Tech Contributor
Joined: Oct 2008
Posts: 1,378
Likes: 11
From: St Louis MO
NPP fully closed on a cam and header setup can sound little tinny (almost exhaust leak sort of sound), especially at low RPM.
Using collars to hold the valves partially open you can dial in the sound level that is tollerable within OEM limits of other vehicles when closed, about 25% open works for me.
https://www.corvetteforum.com/forums...duel-mode.html
Using collars to hold the valves partially open you can dial in the sound level that is tollerable within OEM limits of other vehicles when closed, about 25% open works for me.
https://www.corvetteforum.com/forums...duel-mode.html
Racer
Joined: Jan 2014
Posts: 400
Likes: 37
From: Lone Star State
[QUOTE=EnginerdVT;1587758309]Don't have any with the flaps shut on hand but here is my H/C/I Z on ZR1/11+ Z06 NPP mufflers and 2" ARH headers with cats (Flaps Open)...
That does sound Bad ***, what do your neighbors think?
I have been doing a cold start with the garage door down, it's still freaking loud.
That does sound Bad ***, what do your neighbors think?
I have been doing a cold start with the garage door down, it's still freaking loud.
Drifting
Joined: Jul 2013
Posts: 1,342
Likes: 89
From: Maryland
When I start it, I immediately shut the valves and I drive it during the week to work at 6:30 in the morning with no issues. It is SIGNIFICANTLY more quiet. I'll try and take a vid this weekend! Having that ability to quiet it down for a phone call or early/late arrivals and departures is a priceless capability.
Burning Brakes
Joined: Jul 2013
Posts: 823
Likes: 7
From: Rosewood Heights IL
I just swapped my mufflers from Corsa Sports with cam, longtubes, catless mids to NPP.
Best. Decision. Ever.
NPP is SOOOO much better than the constant noise of Corsa. The sports were brutal at idle and I work nights so late nights were out of the question. Now I just close the mufflers and drive away in peace. Then open them and they are just as loud as the sports.
I had the same decision, I went with NPP and it's awesome.
Best. Decision. Ever.
NPP is SOOOO much better than the constant noise of Corsa. The sports were brutal at idle and I work nights so late nights were out of the question. Now I just close the mufflers and drive away in peace. Then open them and they are just as loud as the sports.
I had the same decision, I went with NPP and it's awesome.
Advanced
Joined: Feb 2014
Posts: 88
Likes: 5
From: New Jersey
What would be the power difference between the 2?
I am on my way to do the same thing. I have an 08 with the npp and have lg long tubes coming in and planning to do a cam swap soon too. The long tube collect into a 3in and the npp (i believe) is a 2 1/2 in. I like my npp but what would be the hp/tq difference if I when with a 3 in exhaust like corsa?
Dont mean to steal the thread, I am just wondering.
(also thinking about getting a z06 Dual Mode exhuast for cheap and doing the sound modd for it since it is a 3in)
I am on my way to do the same thing. I have an 08 with the npp and have lg long tubes coming in and planning to do a cam swap soon too. The long tube collect into a 3in and the npp (i believe) is a 2 1/2 in. I like my npp but what would be the hp/tq difference if I when with a 3 in exhaust like corsa?
Dont mean to steal the thread, I am just wondering.
(also thinking about getting a z06 Dual Mode exhuast for cheap and doing the sound modd for it since it is a 3in)
Last edited by gskomes; Sep 5, 2014 at 01:12 PM.
Thread Starter
Instructor
Joined: Apr 2014
Posts: 168
Likes: 0
From: Tracy Ca
I just swapped my mufflers from Corsa Sports with cam, longtubes, catless mids to NPP. Best. Decision. Ever. NPP is SOOOO much better than the constant noise of Corsa. The sports were brutal at idle and I work nights so late nights were out of the question. Now I just close the mufflers and drive away in peace. Then open them and they are just as loud as the sports. I had the same decision, I went with NPP and it's awesome.
Thread Starter
Instructor
Joined: Apr 2014
Posts: 168
Likes: 0
From: Tracy Ca
When I start it, I immediately shut the valves and I drive it during the week to work at 6:30 in the morning with no issues. It is SIGNIFICANTLY more quiet. I'll try and take a vid this weekend! Having that ability to quiet it down for a phone call or early/late arrivals and departures is a priceless capability.
Burning Brakes
Joined: Jul 2013
Posts: 823
Likes: 7
From: Rosewood Heights IL
Open and closed at idle on my car. Listen closely and you can tell. My phone focuses on engine noise when they close so it sounds similar, but it's a huge difference.
Longtubes, catless mids, NPP, and a cam.