Cavi

Okay, so I pulled the trigger and bought a used set of z06 npp mufflers which I will install on my 2006 base C6 .
Couple of questions, can I run the mufflers before I install the whole vaccum setup? Second, what happens if I just hook the vaccum line to the mufflers without buying the whole NPP in a box?
Third, if I install the NPP in a box and have it in the closed position, will it open on it's own at a certain rpm anyways?
Last (for now), where is the vaccum port on the LS2, picture anyone?

talon90

Ok. Z06 bi-mode mufflers are not NPP. NPP is the RPO for the bi-mode mufflers on base coupes and convertibles and Grand Sports. Since they are standard on the Z06, they don't have an option code (RPO) they are simply bi-mode mufflers.

Yes, you can install the mufflers just like any other muffler. Before or after the control strategy is irrelevant.

If you hook an uncontrolled vacuum line to the mufflers it will close the mufflers as long as there is adequate vacuum pressure from the source and they will open when it looses sufficient pressure to keep them closed. It will also likely manifest itself as a vacuum leak at your manifold.

The system in use for the OEM application has a vacuum accumulator tank to supplement pressure differences in the system during times of high demand (heavy acceleration) as well as a controller designed to limit operation.

The NPP in a box has a valve built in to cap off pressure drop (simulating the accumulator of the OEM system) to prevent unwanted opening and operation of the valves under load).

The vacuum port on a LS2 is at the back of the manifold on the drivers side just aft and to the right of the cylinders. It is a small T shaped fitting.

Top_Fuel

Before you start unbolting stuff, we need to know exactly what mufflers you just purchased. Understand that the only true bolt-on mufflers that will work on your 2006 are dual-mode ("NPP") mufflers from a 2008 (non-Z06) C6.

If you have NPP mufflers from a 2009 or later C6, these also won't bolt directly onto your car unless you also have the mid-pipe from a 2009 or later car.

If you have Z06 mufflers, they won't bolt onto your car without some welding mods (because the pipes are a larger diameter).

Cavi

they will require some welding as they are from a Z06, I am aware of this as is the shop that will be doing the install, I felt the price justified going this route, plus, I still have a set of stock mufflers, which I figure can serve as psrts donors for the weling shop!!!
Okay so I will order the NPP in a box, if it is set to the closed valve setting, do the valves stay closed or do they open at a certain RPM?

Top_Fuel

With NPP in a Box, the valves will remain closed if that is the current setting. The RPMs won't matter. If you want a controller that lets you control the valves according to RPM, look into the Exhaust Commander instead of NPP in a Box.

Do you also know that Z06 mufflers aren't as loud as NPP mufflers? If you want your Z06 mufflers to sound as good as NPPs, you'll need to consider doing the Z06 Muffler Mod to them before installing them.

CDaniel525

If you are going to leave stock exhaust manifolds & cats in place, youll want the muffler mod to really get a great sound! If you are going to add headers in the future, leave the z06 mufflers alone... I have LT headers, catless Xpipe and un modified z06 mufflers and it really screams!! but if it had the muffler mod I think it would be obnoxious!

BAblackvette

I would definitely do the muffler mod, especially if you are installing mild to wild.

Otherwise, I would just hook up the mufflers without M2W and let them run open all the time. My understanding is, Z06 mufflers on a C6 without the muffler mod are pretty tame (assuming stock manifolds/cats), but sound good.

brooklync5

Don't bother installing them without the Vacuume lines and Npp in a box. They will do nothi g for you and sound like any other stock exhaust. Why do the work twice?

Cavi

not planning on doing it twice, just I will install the NPP in a box and my muffler guy will install the mufflers, this will happen on two different days, may even have a week in between. Just wanted to be sure I was okay to run the mufflers before I installed the NPP in a box

Cavi

If I wanted to run them open all the time what do I need to do, can that be done without the NPP in a box?
I am just trying to figure out where I am going.

talon90

Yes, if you want to run them open all the time, this is accomplished without vacuum as they default to open. The vacuum closes the valves so if you never want them closed, no vacuum install.

bill K

I just finished the same set up on my 2005 base. The muffler shop charged me $225.00 for install, they needed to use my old exhaust due to the fact I have an A4. the 3 " pipes would not go through the opening near the trans. So he cut and used my origional exhaust pipes. I am not sure if you will have clearance if you have a stick. I had the install done about 2 weeks ago and what happens is without NPP in a Box valves stay open, I just today installed Wild to Mild today took about 1.5 hours. You could run this exhaust with out any vac. I did find some droning thats why I installed the kit. Just have them installed and run it for a week or so and see how you like them. they really are a nice sounding exhaust open.

Cavi

I am planning on exactly the same path as you went, my only issue is that my stock exhausts are still with the PO and he keeps saying he will drop them off but still waiting... also I thought the manual transmission had more clearance than the auto?

Lexicon

My NPP system is sitting on the car but I bough the whole thing for $400 from headers to mufflers. hardest part was getting the old stuff off. I don't have any lines for the NPP run at this time. All that means is that it is open all the time.

I bought the add a circuit and the exact same vacuum solenoid used on the B&B system. My FAST will arrive shortly and has a vacuum port. I will run the lines and put in a dead pedal switch myself.

I suggest you buy the whole system then it is just a bolt on install....except....I ordered new gaskets for the headers and UPS is slow.

Cavi

you got a great deal congrats
My deal was okay, just not as good, my muffler guy will do fine installing so no worries.

GRG

The vacuum hook up at the rear of the motor is is very ( underline very) hard to hook up to. When you order the NPP in a box get the EZ vacuum hook up at the front top of the motor. It comes with instructions and photos of the whole operation. You will be doing yourself a BIG favor and the EZ hook up is only a few dollars more. Works perfect. You can set the NPP to start up in the louder mode or the quiet mode. Either way you can push the control button to change it. You would have been better off to get a NPP system off of a non-Z06 non-ZR1 2008 or older model, I hope the muffler man is good at cutting and rewelding. Good Luck

Cavi

he is great, and most of the used ones I saw were for the Z06 and even those seemed to be priced at or over 700, new ones for the C6 are lie 1200, so when I got mine for under 600 I jumped on it, the muffler guy will charge me less than 100 for the install.

BAblackvette

incorrect, the exhaust runs with valves open with no vacuum. They will sound quieter then an NPP exhaust, but considerably louder then a stock exhaust.

BAblackvette

Definitely get the E-Z hook up thing. All you have to do is take off the FRC, and install a little T type hookup thing to tap into the intake manifold vacuum. Then run the vacuum lines back, cable tying them away from hot spots like the exhaust manifolds, over the tunnel plate above the mid-pipe, and finally to mate with the connector on both ends of the mufflers.

Top_Fuel

OP...print off a copy of the Z06 Muffler Mod Instructions and take them with you when your exhaust guy does the install. See what he will charge you to do this mod. If you install Z06 mufflers on an otherwise stock C6, it will sound good...but not as good as it will sound with modded mufflers. Hey...you're going this far so toss the guy a few more bones and get the mufflers done!