NPP Exhaust Valve Controls - Page 4 - ZR-1 Net Registry Forums

XfireZ51 · 04-05-2014

Quote:

Originally Posted by mike100

That studded bracket was quite useful on my installation also.

Mike,

The way I have this wired would allow me to use the wireless fob IF I can determine how to make it work. Altho don't have a ton of initiative at this point on that front.

XfireZ51 · 04-05-2014

OK. Time to see how the check valve works.

Here's the NPP control installed in rear quarter

And then here's the NPP control working w the check valve in-line. so this will give me a ON/OFF capability depending on which way the console rocker switch is set.

mike100 · 04-05-2014

Yeah...I gotta add an off switch to mine as well...easy enough, but where to put it?

The NPP trick is all well and good, but it is still very loud when they open up (got pulled over again). So... I need the totally turn it off when I'm in certain parts of town since the temptation to pull a gear is just too strong sometimes.

XfireZ51 · 04-11-2014

Bolted a pair of borrowed seats from PW and so I was able to drive the car. Took it this morning for a wheel alignment. This gave me a chance to try out the NPP control. It really sounds sweet driving w the actuators closed. You get a nice purrrrr from the back. There is some 'boom" at 12-1300rpm, but flip the switch and it really gets louder. Very noticeable. The switch works just great. An hour after shutting down, the actuators were still closed indicating that the system was holding vacuum very nicely.

Karl · 05-09-2014

Will something like this work instead?

http://m.ebay.com/itm/150727996468?nav=SEARCH

XfireZ51 · 05-09-2014

Mike,

I ran a ground interrupt circuit to a simple toggle switch I installed in one of the "cup holder" recesses of the console. That, together w the vacuum check valve is working well in terms of either keeping the actuators fully open or closed shut.
I'll also reiterate that a portion of the loudness and flabby sound of the exhaust is related to a "too rich" fuel mixture. I observed that sometime ago and have confirmed it with my latest tuning sessions working w injector offset values.

04-05-2014	#32
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,708	Re: NPP Exhaust Valve Controls OK. Time to see how the check valve works. Here's the NPP control installed in rear quarter And then here's the NPP control working w the check valve in-line. so this will give me a ON/OFF capability depending on which way the console rocker switch is set. __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX

04-05-2014	#33
mike100 Join Date: Feb 2011 Location: San Marcos CA Posts: 1,802	Re: NPP Exhaust Valve Controls Yeah...I gotta add an off switch to mine as well...easy enough, but where to put it? The NPP trick is all well and good, but it is still very loud when they open up (got pulled over again). So... I need the totally turn it off when I'm in certain parts of town since the temptation to pull a gear is just too strong sometimes.

04-11-2014	#34
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,708	Re: NPP Exhaust Valve Controls Bolted a pair of borrowed seats from PW and so I was able to drive the car. Took it this morning for a wheel alignment. This gave me a chance to try out the NPP control. It really sounds sweet driving w the actuators closed. You get a nice purrrrr from the back. There is some 'boom" at 12-1300rpm, but flip the switch and it really gets louder. Very noticeable. The switch works just great. An hour after shutting down, the actuators were still closed indicating that the system was holding vacuum very nicely. __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX

05-09-2014	#35
Karl Join Date: May 2013 Location: Chicago Posts: 980	Re: NPP Exhaust Valve Controls Will something like this work instead? http://m.ebay.com/itm/150727996468?nav=SEARCH __________________ 1993 ZR-1 #211 Yellow On Beige Beast #2 1992 ZR-1 #427 Black On Black Sold 1985 L98 Blue On Blue Sold

05-09-2014	#36
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,708	Re: NPP Exhaust Valve Controls Mike, I ran a ground interrupt circuit to a simple toggle switch I installed in one of the "cup holder" recesses of the console. That, together w the vacuum check valve is working well in terms of either keeping the actuators fully open or closed shut. I'll also reiterate that a portion of the loudness and flabby sound of the exhaust is related to a "too rich" fuel mixture. I observed that sometime ago and have confirmed it with my latest tuning sessions working w injector offset values. __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX