froggy47

I have to deal with a sound limit rule where I autox. Is there a controller that actually lets you set the % close to open of the butterflies on a stock npp system?

Anyone want to coach me on how to built one, maybe with a fuse extender to a switch that has a rheostat/dimmer/something on the end in the cockpit?

Nowanker

The vacuum solenoid is simple on/off... when mine went bad I used a more robust aftermarket replacement that a lot of the 'tuner' crowd uses as a PWM turbo boost controller. With enough ingenuity, you could probably come up with a similar setup to hold the flaps 50% open, or whatever...
What's your noise limit?
At Laguna I made the 90 dB limit (through turnouts) with the flaps closed, but blew almost 95 with the flaps open.

Nowanker

You could also come up with some kind of stop, to limit how far the open travel is...

froggy47

90 is a warning 94 is out and times are cancelled.

froggy47

Maybe an adjustable mechanical stop on the hardware outside the pipe.

Nowanker

90 is pretty quiet... Even with the flaps closed, I doubt I would have made that without the turn outs.

froggy47

I plugged the fuse back in so they work as factory for now.

crimlwC6

On C6Zs, I've seen the use of bailing wire to hold the NPP closed. I don't know if the NPP changed between models.

moose.b3

I've done the bailing wire method with success at Laguna Seca. But you can accomplish the same thing by just undoing the control arms from the flaps with a screw driver and wedging them against the flap mechanism forcing the flaps closed. This lasted all day and I never got a meatball flag. Sorry I don't have a picture so it would be a little more clear but you should be able to figure it out.

froggy47

How well do these cars run with 1/2 the exhaust stuffed up?