Functioning NPP for $50

[Deke736]

Originally Posted by ilirg

OK got my zl1 exhaust, all the vacuum hoses and vacuum switch. Quick question, does it make a difference which port on the switch the vacuum lines go in? And does the button on the switch need to be pushed down or pulled out to work with bi-mode. Can't wait to do this, damn snow through a wrench in my plans today.

It doesn't matter how you run the lines. It's a simple in one side out the other. Same with the switch direction. If you want to change it, swap your lines. You'll be able to tell right away which is open and closed.

[ilirg]

Thanks!

[ilirg]

Sorry one more question, where the heck is that hole in the firewall? Im having the hardest time trying to locate this thing!

[Dnm1012]

Will b doing this soon.

[Deke736]

Originally Posted by ilirg

Sorry one more question, where the heck is that hole in the firewall? Im having the hardest time trying to locate this thing!

It can be hard to find! Reach up behind the brake fluid reservoir toward the corner of the windshield and you should be able to find it. There is probably a plug in it that you will have to remove. I have wires running through mine as a guide and I still struggle to find it sometimes. Or, you can lay down in the drivers seat and pull the carpet back and find it that way.

[ilirg]

Thanks, ended up getting it though the hood release cable hole! Only thing I'm worried about is that its a little tight fit, it doesn't look like the hoses are pinched but I'll find out tomorrow once everything is installed.

[ilirg]

Works like a charm. Car sounds bad ass! Thanks Deke!

[Deke736]

Originally Posted by ilirg

Works like a charm. Car sounds bad ass! Thanks Deke!

Nice job!

[ilirg]

One more question! I just drove with the switch open and can hear the air coming from the switch, yours was installed in the cabin right? Is that something you just deal with or am I missing something? I think I might move the switch into the engine bay and keep it open all the time, I actually like the sound open better, no drone at all.

[Deke736]

Originally Posted by ilirg

One more question! I just drove with the switch open and can hear the air coming from the switch, yours was installed in the cabin right? Is that something you just deal with or am I missing something? I think I might move the switch into the engine bay and keep it open all the time, I actually like the sound open better, no drone at all.

You probably just need a smaller internal diameter vacuum line. If it's making noise, then it isn't sealing properly. You could move it, or put a tight zip tie on it. That should solve it.

[Dnm1012]

I bought this vacuum switch and I have decided to not go this route. I will sell the unused switch for $16 + shipping. I have not used it and just received it on 1/24/2014. Let me know if ur interested in buying it.

[sub zero]

Where can i find the vacum switch ?

[Denis]

awesome write up. on the hunt for an NPP exhaust as we speak. this is awesome to know. and seems very simple. any info on where to get those switches?

[4RSS FED]

Thanks for the great write up. I usually don't have too much to contribute but here are some notes that may help someone who goes this route.

I have had my exhaust installed for a week but I just finished running the vacuum lines today. It took a little longer than I had hoped but the end result was worth it. I wound up mounting my switch under the dash. It took some modification to get it to work where I mounted it, but it is accessible while driving. Closed it runs nice and quiet, until you step on it. The valves will be fully closed at about 10" of vacuum (at idle you will be in the 17 in Hg range). Anything less than that they start to modulate open until you reach 0 in Hg (fully open).

That vacuum switch design, ports vacuum to the atmosphere when it is in the open (extended) position. So if you hook up your lines the wrong way you may hear the hissing noise that was described in an earlier post. See the last photo where you can see the white table through the top vacuum port labeled exhaust. The bottom port is covered whether open or closed.