Homemade NPP system
Thread Starter
Safety Car
Joined: Aug 2017
Posts: 4,243
Likes: 1,133
From: North Myrtle Beach SC
Homemade NPP system
Just took off my Borla S ( which is for sale if anybody is interested) when I did headers and off road mid pipe. Put on npp axle back. To actuate it, I bought a small vacuum pump on eBay, a vacuum T, and a couple pieces of vacuum line. Right now it is powered through the cigar lighter but will be putting a dedicated switch, just need to figure out what I want and where to put it. When I power it up, valves close immediately. When I power it down, it takes about 90 seconds for the vacuum to bleed off through the pump.
exhaust system is very loud when open under full throttle but tolerable driving around. With the valves closed, it becomes very civilized. Neighbors definitely like the lack of roar when starting in the garage. Whole thing cost under $25. Happy with how it works.
exhaust system is very loud when open under full throttle but tolerable driving around. With the valves closed, it becomes very civilized. Neighbors definitely like the lack of roar when starting in the garage. Whole thing cost under $25. Happy with how it works.
Pro
Joined: Dec 2007
Posts: 595
Likes: 241
From: Maine
2022 C6 of the Year Finalist - Unmodified
Sounds similar to what I did on my 2007 base (that I've now sold) when I added NPP mufflers to it. Worked very well. I installed a vacuum solenoid for activating/deactivating the valves though. That allows for immediate switching. Had the pump run whenever ignition was on to have vacuum ready whenever I needed it. This is the one I used: https://www.summitracing.com/parts/uac-sw9001c I did have it run off manifold vacuum at first but preferred the dedicated vacuum pump at the rear.
Pro
Joined: Dec 2007
Posts: 595
Likes: 241
From: Maine
2022 C6 of the Year Finalist - Unmodified
Pro
Joined: Dec 2007
Posts: 595
Likes: 241
From: Maine
2022 C6 of the Year Finalist - Unmodified
When I was running mine off manifold vacuum, I had a check valve and a small vacuum chamber that I made with 3" PVC pipe and some end caps. The valves never opened during WOT. Running off a separate vacuum pump wouldn't have any effect at WOT since you aren't using manifold vacuum anyway.
Thread Starter
Safety Car
Joined: Aug 2017
Posts: 4,243
Likes: 1,133
From: North Myrtle Beach SC
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,104
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
The vacuum pump system is pretty much how the original M2W worked, before they changed it to the present system around '08-'09. The pumps didn't last too long, since even a small leak required them to run too often when the stout flapper valve springs were working in the opposite manner.
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You just need to find one that will close the passages on it when it powered up (one side into the lines, other port not piped in), then open the ports when it loses power, to allow air to come into the open port to flow into the NPP vacuum line dump the vac *** pressure.
Check something like this, to see if it needs power to open or close the two ports passages.
Thread Starter
Safety Car
Joined: Aug 2017
Posts: 4,243
Likes: 1,133
From: North Myrtle Beach SC
Just ordered a vacuum solenoid valve that is naturally open. I can wire this with my vacuum pump so they are both either on or off. When power is cut, it will allow atmosphere to come into lines and open the valves, at least that’s how I see it. Should be here within a week. If it works as planned, I will wire in my power switch and mount it. 🤞🤞
Instructor
Joined: Sep 2021
Posts: 175
Likes: 58
From: Long Island, NY
12 volt vacuum solenoid dump valve T'd into the line is the solution, to release the vacuum in the lines quickly as you shut off the pump.
You just need to find one that will close the passages on it when it powered up (one side into the lines, other port not piped in), then open the ports when it loses power, to allow air to come into the open port to flow into the NPP vacuum line dump the vac *** pressure.
Check something like this, to see if it needs power to open or close the two ports passages.
https://www.amazon.com/Universal-Con...03R43J2C&psc=1
You just need to find one that will close the passages on it when it powered up (one side into the lines, other port not piped in), then open the ports when it loses power, to allow air to come into the open port to flow into the NPP vacuum line dump the vac *** pressure.
Check something like this, to see if it needs power to open or close the two ports passages.
https://www.amazon.com/Universal-Con...03R43J2C&psc=1
I built the same setup and it keeps the valves closed at WOT. The in line Mac solenoid releases the vacuum and opens the valves instantly.
Thread Starter
Safety Car
Joined: Aug 2017
Posts: 4,243
Likes: 1,133
From: North Myrtle Beach SC
Finally got my solenoid and installed it. So with power on, vacuum pump is on, solenoid is closed, HOA approved exhaust sound. With power off, vacuum pump is not running and solenoid opens to release vacuum, opening flaps in npp. Loud.
put a toggle switch below the rear hatch release button on lower dash.
put a toggle switch below the rear hatch release button on lower dash.
Instructor
Joined: Sep 2021
Posts: 175
Likes: 58
From: Long Island, NY
Finally got my solenoid and installed it. So with power on, vacuum pump is on, solenoid is closed, HOA approved exhaust sound. With power off, vacuum pump is not running and solenoid opens to release vacuum, opening flaps in npp. Loud.
put a toggle switch below the rear hatch release button on lower dash.
put a toggle switch below the rear hatch release button on lower dash.
Pro
Joined: Nov 2016
Posts: 647
Likes: 103
From: Aurora IL
nice. here is mine for those who want to stay away from any electrical work.
My budget NPP Controller - CorvetteForum - Chevrolet Corvette Forum Discussion
My budget NPP Controller - CorvetteForum - Chevrolet Corvette Forum Discussion