Attz0r

I know this question has probably been covered a million times but I couldn't come up with the exact answer. My question is about the vacuum lines running to the intake, my buddy has a 2012 grand sport and his car has a fuse he pulled to keep the flaps open all of the time. I'm not really sure how this could work on my car seeing as I won't be connecting to anything other than the back of the intake manifold to provide vacuum pressure. So when I install mine, will the muffler flaps operate properly by just installing the vacuum line? Or is there something else required to make it work properly?

Thanks in advance for any help!

Turbo6TA

There is a lot more to the factory NPP system then just running a vacuum line from the intake manifold back to your newly installed NPP muffler actuators.

Your best bet is the purchase what is called "NPP in a Box".

All you need then is the NPP mufflers and everything else is included in the "NPP in a Box".

Perfect for the C6 that did not come from the factory with the NPP option.

Lots of vendors sell them ... Here is just one:
http://www.southerncarparts.com/corv...FRFahgodb8IKTg



.

crystallinity

I believe this is what you'll need.

http://www.southerncarparts.com/corv...st-p-2724.html

Attz0r

So without the retrofit kit, it will not function? If so, I guess its going to be real loud for a while, lol.

BigBlok502

With the vacuum line hooked up and the engine running the valves will close and be quite. If you go to WOT (wide open throttle) the vacuum line will lose vacuum and the valves will open and be loud, when you let off the gas the valves will close again and be quite.

If you don't connect a vacuum line, the valves will remain open all the time and be loud.

Sayfoo

You can also install a solenoid switch to block/open the vac lines. I bought a 12v switch off ebay and installed a toggle switch near my knee on the dash. You can also buy a wireless controlled switch to use with a fob, but I find the toggle switch to be the simplest and most reliable.
You can also T off a remote vacuum canister ($12-$15 at AZ) that will help keep the vac up when going up a long hill, etc.
There are other posts that tell the details, most from 4-5 yrs ago.
Or, buy the kit referenced above.

Attz0r

Ok, so if I do connect the vacuum lines to the back of the manifold (LS3 car), the flaps will operate at WOT? That's really what I want to know, I want it to work like that, WOT cut outs open idle/cruise, cut outs closed.

MH663

No they will not.

MH663

Your car WILL NOT function like a stock system. You need the NPP in a box and you will have to remotely open and close the flaps manually. Period!

I thought there was a system that did work like a factory system at one time but I can't remember for sure?

Just an FYI...save yourself the aggravation and just go ahead and remove the intake. You can get to the vacuum nipple without doing so but it is a PITA and you will be cussing all along the way. Not to mention you can have the intake off and back on while still cussing at the nipple because you just can't quite get to it.

Attz0r

Perfect, that's all I needed to know, glad I asked before wasting my time trying to plumb this for no reason. I'll pick up one of the install kits later.

MH663

Cool... no need to drill a hole in the storage compartment either. Use the alternate pathway as detailed in the Sticky Thread. Use RTV to stick it to the underside of your storage compartment.

Attz0r

I may already have holes for the nitrous bottle and lines sooooo..

BigBlok502

I installed a switch on my console, this is before I installed Kooks LTs:

mrk1957

I plumbed mine into the brake booster vacuum line. A lot easier than the intake route.

sfrank2886

I am also getting ready to do this on my LS3 when my headers and x pipe arrive. I have the NPP in a box, and the muffs standing by. You really want to be able to operate it independently and not only at WOT. At-least in my opinion, better than stock. If you want you can also utilize a toggle switch if you don't want to use the fob as mentioned earlier.

Jay462

I wouldn't tap into any vacuum lines at all. Do what I did and use a vacuum pump. That way, if you ever have to chase a vacuum leak, it will be to a small pump and not your engine. Also, this is easy because you don't have to run a vacuum line the length of the car.

I have a switch under the dash. On = quiet. Off = loud as **** with headers and no cats :

https://www.corvetteforum.com/forums...ne-intake.html