CHUXDRM

Okay, I've decided to put the NPP mufflers back on (after the emissions recall installed the x-pipe with additional cats (discussed in a previous post)). But when the NPP's were on before, I was getting a drone when the flaps were closed and engine at low rpm under load (not enough vacuum to hold them closed). This is evidently a common problem as I've found in my searching. I think my solution may be installing a vacuum storage canister, again searches show many have done this.

My problem is, I can't find exactly how to plumb it into the system. Does the canister have an "in" and an "out" port, or just an"in"? And do I just tee it off the main vacuum line going to the NPP vacuum controller?

Thanks for your help.

Dcasole

I don't have a canister and mine stays closed , you sure that's the problem ?

Dave

MKenM

I'm sure you know the flaps are closed until you hit about +- 3500 RPM's. Have someone work the gas pedal while you watch the butterflies at a standstill. It may be the flaps are partially open and need an adjustment of the nut on the vacuum unit.

george536

The original has just one where it gets "T" into the system. If you want something to put in line with an in and out http://www.amazon.com/gp/aw/d/B000CO...f3L&ref=plSrch

That one has a built in check valve also so vacuum stays in

CHUXDRM

No, I'm not. Just deducing from some other threads I found where guys were having the same problem.

CHUXDRM

I think you're referring to the way NPP's work if equipped on car from factory with flaps opening at 3500. Those units had a canister. I added NPP with the Sunset Orange Creations controller.

What "adjustment nut" on the vacuum unit do you refer to?

weathermaker

I don't have NPP, but this is how I think it should work. When engine is off, the valves are open. When started the vacuum from engine closes the valves. When engine gets to selected RPM either factory or aftermarket, the valves open by less vacuum on the diaphragm. So if yours are opening when they should be closed, you're losing vacuum. A tank will store more vacuum and may solve the problem, but you may have a leak also. I think the tank could be just teed into the line and do the trick. It could hold the valves open a little longer until it empties. Just my thoughts.

Dcasole

Unless you have a stick and are really " LUGGING ' it down low, there should be plenty of vacuum to keep the valves closed

I have an Auto and mine is quiet when closed no matter what , even when I jump down on it hard , which would drop the vacuum down to almost nothing my NPP's stay quiet.

I would do what the others suggested and make sure that
1- the valves are closing all the way when you pull a vacuum on them , the rods are adjustable and if you bought them from someone else maybe they adjusted them to stay open a bit
2- The vacuum is not leaking down for some reason

you can buy a cheap hand held vacuum pump to test it

good luck and let us know how it turns out

Dave

Dcasole

"What "adjustment nut" on the vacuum unit do you refer to?"

I to use NPP in a box and like I said above mine are quiet in the closed position . heck my Wife's E class Mercedes is louder

You will see a rod coming out of the Vacuum diaphragm on each muffler , this rod is threaded with an locking nut . sometimes .... this nut can come loose or someone can adjust the valves to say open a bit at idle

The also sell a set of locking collars that some folks use because they want their car to be a bit louder when the mufflers are in the closed position , these go on this rod and you can adjust them so the vacuum units do not close all the way

check and make sure no one put collars on

Dave