NPP exhaust valves on my SW 3" pipe set

[XfireZ51]

Mike,

I see you have mounted the valve on the inboard side of the muffler. The FBI valves are on the outboard side.

[-=Jeff=-]

Originally Posted by XfireZ51

Mike,

I see you have mounted the valve on the inboard side of the muffler. The FBI valves are on the outboard side.

He did it on the the straight through tube on the exhuast, I guess it really would not matter though, still gets the job done

[GOLDCYLON]

Originally Posted by XfireZ51

Mine are connected via what was the vacuum line for the canister and plugged into driver's side plenum port. The one that was previously used for the secondaries. No switch so the NPP valves open progressively like vacuum secondaries on a Quadrajet carb. Sounds a bit like it too. BBBWWWWAAAAAAAAAA! Pretty sure Pete, Al, and BobGs set ups are similar.
Pete has his valves grafted onto B+B tips, Bob and I use the Z06 tips.


Paul,

Were u working on another source for the valves? It is an Easter Egg hunt to find someone who'll cut the tips off and sell for a reasonable price.

Dom do you think these would make a difference on a corsa system ?

[GOLDCYLON]

Originally Posted by XfireZ51

Mike,

I see you have mounted the valve on the inboard side of the muffler. The FBI valves are on the outboard side.

its a left coast right coast thing... actually thats where his straight throughs are on the system. I think the Corsas are outboard like the FBIs setup as well.

[-=Jeff=-]

brand new 2.5"

http://www.ebay.com/itm/380606319348...84.m1423.l2649

http://www.ebay.com/itm/Stainless-St...item58a4d37c31

[WARP TEN]

Originally Posted by GOLDCYLON

Dom do you think these would make a difference on a corsa system ?

The Corsa is straight through on both pipes so it wouldn't make any difference. If you put the valves on a Corsa you would simply restrict flow. Might lower sound intensity a bit. As I understand it, on the Z06 and the SW one side is more muffled than the other, although I could be wrong. -Bob

[mike100]

Originally Posted by -=Jeff=-

Mike,

you needed the tips as well correct? mind if I ask how much you paid for the NPP mufflers?

I have seen the valves themselves on eBay for about $100 each for new ones

I got the mufflers for $300. This is a good price for Z06 mufflers even though it was more than I wanted to pay. It did fit, solved my problem, and looks like it is a vette part.

Interestingly, when I was at the local muffler place, the guy gave me a 2.25" exhaust flapper from a twin turbo BMW 335 (made by Boysen). They use one per car and they are full open with half the vacuum signal (only 5" vac vs. 10" on the C6 version). This may be a source of decent valves if you can score take-off 335 mufflers.

[mike100]

Originally Posted by GOLDCYLON

its a left coast right coast thing... actually thats where his straight throughs are on the system. I think the Corsas are outboard like the FBIs setup as well.

Yeah, the SW muffs have the inlet on the inboard part of the muffler.

[mike100]

Originally Posted by Paul Workman

Really interesting setup Mike!

I think I have the jist of what you've done, but pls allow me summarize what I think I understand, and then maybe you can clear up where I "lost your trail".

The adjustable vacuum switch receives vacuum from the "T" connection that also feeds vacuum to the MAP (under the ECM on a 1900 Z). At or below 12" Hg, the switch closes, activating the vacuum solenoid.

Normally, this solenoid connects plenum vacuum to the NPPs - keeping them closed. But, when plenum vacuum drops below 12" Hg, the vacuum solenoid receives its signal and "vents" the vacuum to the atmosphere (through the foam filter), thus relaxing the NPP diaphragms and thus opening the exhaust gates.

Now, if not already, is where I get a little...

You referenced a second MAP, and dedicated vacuum solenoids for each NPP valve. I get the reasoning for the dual system - decreasing bleed time - but I'm missing a link here...

It looks like the vacuum solenoid (pictured) would directly operate the NPPs. But, it is this additional MAP you mentioned, and the electric/vacuum circuitry at the NPP end that has me . I gather the system as it is now is a "work in progress", is it? By that, I mean the NPP end of the setup is yet to be upgraded for individual operation???

As you can see, Mike, I wandered off the path somewhere...

Ok, there is some reference to the 2nd MAP sensor- that was meant for another non-ZR-1 forum where people aren't aware of the function of our vacuum secondaries (for those of us who still run them anyways).

To clarify, manifold vacuum closes the muffler flap- they are open at rest.

-To have run the valve straight from the secondary pump would have had the logic 180 reversed- plus they draw too much air and would have messed up the function probably.

So what I did was use the normally open contacts on that adjustable vacuum switch that triggers another vacuum source (through a GM EGR solenoid) when the secondary activates. What it actually does is release the actuator vacuum to the vent(when u step on it) as the solenoid is allowing vacuum through in the off condition (during cruise conditions). It is sort of reverse logic.

The vacuum source is NOT plenum vacuum. it is an is a check-valve isolated source (the vacuum ball under the d/s headlamp.

[XfireZ51]

The system here in FBI land is using the DynoMax Utlraflow. These are straight thru w either tube. I didn't ask about Mike's positioning because of performance.
Rather it was for fit. Perhaps the SW muffs allow positioning on the inside. The DynoMax really have a better fit with the valve on the outside.
Al or Pete could offer better insight on this.