08-20-2013, 02:16 PM | #1 |
COTW 12/3/12
Drives: 2012 Ashen Gray ZL1 Join Date: Aug 2011
Location: Glen Carbon, IL
Posts: 3,279
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Functioning NPP for $50
After seeing several threads of people trying to hook up their NPP exhaust to a Camaro without that option, I felt that I should make a thread explaining a cheap and easy way to get a fully functioning NPP system without buying an expensive controller. The method I explain below even gives a little more control over the NPP since it will allow you to start the car with the valves closed, unlike the factory system.
Here is basically what we did on my buddy's SS (LS3) when he added the ZL1 exhaust: We replaced the hard vacuum line shown in this pic behind the throttle body with flexible vacuum hose and a T-fitting. That is not my car in the pic- I just found it on the forum to show which line I was talking about. NOTE: there are also other places to tap into vacuum, like the brake booster, but this is the route we chose for our install. Here is a pic of the vacuum line replacing the hard line and the t-fitting. Here are the connection points of the soft vacuum line replacing the hard line: We then ran another section of vacuum line off the T-fitting along the fuel rail into the cabin through the hole in the firewall behind the brake fluid reservoir. Here is a pic of the routing: We ran the vacuum line in the cabin to a manual vacuum headlight switch from a C3 Corvette like this one: I have found a source for these switches, so PM me for info. Then we ran another section of vacuum line back out the same hole in the firewall and down under the car following the exhaust pipes all the way back (you will want to find a path away from the heat but following the exhaust route). When we got to the back, we used another T-fitting to split off the vacuum line to run to each of the fittings on the mufflers. All said and done, we used probably 35 feet of vacuum line, and 2 T-fittings, and the Corvette vacuum switch. We zip tied the vacuum line where we could to secure it properly. If I remember correctly, we did have to use a larger diameter vacuum line to replace the hard line off the throttle body and used a T-fitting with a reducer built in. All pieces were bought from the local auto parts store except the switch, which I already had from restoring my Corvette. Total investment was around $50 (including buying a switch like the one in the link). Total time to install was about an hour. I had the luxury of using a lift, so it made the job a little easier, but all of this could be done with the car on jack stands. The switch is mounted under the dash and is completely out of view. The system works exactly like the stock ZL1 exhaust does, but without any electrical components. I hope this helps. Let me know if you have any other questions. Last edited by Deke736; 01-24-2014 at 03:36 PM. |
08-22-2013, 07:49 AM | #2 |
Drives: 2010 CAMARO 1SS/M6 BLACK ON BLACK Join Date: Oct 2010
Location: ORANGE COUNTY CA
Posts: 541
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Thanks for posting. Great info.
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08-28-2013, 01:21 PM | #3 |
No Tags/Habitual Violator
Drives: 2012 SIM 2SS/RS & z71 Join Date: Sep 2011
Location: North Georgia
Posts: 2,379
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What size vacuum line and tee did you use?
Did you consider tapping off the unused port in back of the manifold? (assuming you have one) |
08-28-2013, 01:31 PM | #4 |
Drives: 1973 z28 Rs , 2012 SS/Rs Blk/Blk M6 Join Date: Oct 2009
Location: Laguna
Posts: 197
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So of its run only by vacuum how much
Acceleration makes it open? A little or a lot. ? Seems like the factory limited opening at certain rpms for a reason. I'm retrofitting soon and will have questions I'm sure. |
08-28-2013, 02:40 PM | #5 | ||
COTW 12/3/12
Drives: 2012 Ashen Gray ZL1 Join Date: Aug 2011
Location: Glen Carbon, IL
Posts: 3,279
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Quote:
http://m.autozone.com/autozone-mobil...25ry?id=365546 We did consider tapping the port on the back of the manifold, but I have big hands and my method was easier for me. Quote:
I'll put it this way- if the valves are closed and you put your foot in the gas, they open up. When you take your foot off the gas, they close back up. If they are closed and you drive conservatively, they stay closed. I hope this helps. |
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08-28-2013, 09:38 PM | #6 |
German Representative
Drives: 2010 Camaro 2SS/RS IOM Join Date: May 2013
Location: Monroe, Michigan
Posts: 115
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And the switch cuts the vaccum so the butterflies are always open, correct?
__________________
Mathias
Apex intake scoop, CAI intake, Vmax ported throttle body, Kooks LT headers, stock exhaust with NPP mufflers, BMR trailing arms, toe rods, cradle bushing inserts, Hex Vents, Factory Reproduction 41 20x9 and 20x10 |
08-29-2013, 07:12 AM | #7 |
COTW 12/3/12
Drives: 2012 Ashen Gray ZL1 Join Date: Aug 2011
Location: Glen Carbon, IL
Posts: 3,279
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Yes, you can set it to always open as well. The switch allows total control of the butterfly valves.
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08-29-2013, 09:39 PM | #8 |
Drives: 1973 z28 Rs , 2012 SS/Rs Blk/Blk M6 Join Date: Oct 2009
Location: Laguna
Posts: 197
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So we need to figure out how to open at idle like factory system other than no vacuum.
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08-30-2013, 03:14 PM | #9 |
COTW 12/3/12
Drives: 2012 Ashen Gray ZL1 Join Date: Aug 2011
Location: Glen Carbon, IL
Posts: 3,279
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Yes, if you don't just want to set the switch to open at idle.
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08-30-2013, 07:09 PM | #10 |
Drives: 1973 z28 Rs , 2012 SS/Rs Blk/Blk M6 Join Date: Oct 2009
Location: Laguna
Posts: 197
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It looks like the corvette guys make their quiet mode louder using collars on the vacuum solenoid to hold them slightly open. Hopefully I'll get my npp installed soon.
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09-11-2013, 09:03 PM | #11 |
Drives: 1973 z28 Rs , 2012 SS/Rs Blk/Blk M6 Join Date: Oct 2009
Location: Laguna
Posts: 197
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Ok. I got my mufflers and switch and will be installing soon.
Ill let you know how it goes. |
09-12-2013, 05:21 PM | #12 |
Drives: 1973 z28 Rs , 2012 SS/Rs Blk/Blk M6 Join Date: Oct 2009
Location: Laguna
Posts: 197
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Installed
Sounds amazing. |
09-12-2013, 06:53 PM | #13 |
COTW 12/3/12
Drives: 2012 Ashen Gray ZL1 Join Date: Aug 2011
Location: Glen Carbon, IL
Posts: 3,279
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09-12-2013, 07:06 PM | #14 |
Drives: 1973 z28 Rs , 2012 SS/Rs Blk/Blk M6 Join Date: Oct 2009
Location: Laguna
Posts: 197
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Thank you. Npp wild isn't too loud, sounds like a beast, snarling and popping. Great exhaust.
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Tags |
install, npp, tap, vacuum |
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