Tech

Has anyone devised a contraption to force the NPP valves to open more slowly? I'm not talking about changing when they open, but rather how fast they open. I installed ZR1 cans on my car and the on/off nature of the OEM system is a bit obnoxious.

I have a Dashlogic, so I'm not looking for M2W or anything similar that simply allows you to open/close them at will. I want to increase the time it takes to go from full closed to full open without also preventing the valves from closing quickly.

ChoppinVette

Sounds like you're going to need to wire in some sort of stepper motor that works off of the 0-5v TPS signal to slowly open and close the valves.

Dan_the_C5_Man

The stock system runs off of vacuum, so you need to manipulate the mechanical properties of the valve (introduce drag) or switch to some electronic mechanism (open and close the valves via an electronic motor), which sounds like a lot of effort to me.

I wonder if you put a restriction in the line, maybe play with that idea.

Personally, I get a kick out of blasting by slower cars on the gas.. Never really thought about how quickly the valves opened or closed.

Tech

Do you have headers without cats also?

Dan_the_C5_Man

Nah.. I don't believe in running a street car w/o cats - I've driven behind people that do - it's a miserable experience, with all the eye-watering, stinking exhaust smells - my solution, I just drive faster than they do, put them behind me; their 5 HP increase can't match superior skills.

kbreese

I know what you mean man. It's funny how the car sounds relatively tame and all the sudden it's blasting a really loud exhaust note. I think it must scare the **** out of people all the time. I've seen people on the street kinda jump a little and turn like wtf.

Also, one time I asked my fiancé to video tape me launching the car on the highway. She was driving in front of me and I called her and asked her to use her phone. So I got along side here in 3rd gear and hammered it. When the exhaust valves opened up it scared her so much that she dropped her phone. No video for me, lol.

For the record I have LT's too but WITH cats. Even with the cats it's still really loud with the valves open. Also, have a haltech, heads & baby cam.

Tech

I've had the same thing happen!

jayyyw

I was going to suggest this as well..

HOXXOH

Put a simple screw clamp on the rubber vacuum line going to the mufflers. Adjust until you get the desired rate. It's a mechanical solution. No software, electronics, or wiring needed.