What does this mysterious part do?
 

Closeups to show part number. The other pic to show location on car.

What is this part and what does it do? It has vac coming from somewhere back by the turbo, vac coming from the port next to the MAP on the intake pipe, and it (at least on mine) vents to atmosphere. Is this some sort of pressure valve that only allows vent to atmosphere at a given threshold? Any idea what that threshold might be or what triggers it?


https://www.chevyhhr.net/gallery/fil...7/IMG_1205.JPG

https://www.chevyhhr.net/gallery/fil...7/IMG_1206.JPG

https://www.chevyhhr.net/gallery/fil...7/IMG_1207.JPG

Charged air bypass solenoid.

The TC incorporates a wastegate that is controlled by a pressure differential, that is determined by the engine control module (ECM) by means of a PWM solenoid, in order to regulate the pressure ratio of the compressor. A charge air bypass valve also controlled by the ECM by utilizing a remotely mounted solenoid is integrated into the unit to prevent compressor surging and damage from vibrations by opening during abrupt closed throttle conditions. When the bypass valve is open during closed throttle deceleration conditions, the bypass valve allows the air to recirculate in the turbocharger and maintain compressor speed. Within a calibrated range during the closed throttle event, or upon a wide open throttle command the bypass valve will then close to optimize turbo response.

That's pretty clever. I'm an old hotrodder, but sometimes you just can't beat factory engineering.

The solenoid is back on the turbo assy. It's the circular piece with the 3 bolts holding it into the housing. Are you saying that this is just a valve that is measuring the differential against atmospheric (hence the one open hose)?

I'm not too sure the hose should vent to atmosphere. But since I haven't seen an SS in a month or so I don't have the luxury of looking to see where it goes on one. The manual shows the hoses but not where they plug in. :confused:

How about you other SS owners, can you help out???

Oops.

Can someone with an SS look under the hood and tell me if one of the lines in this "tee" part vents to atmosphere???

Looked under the hood and all around, and for the life of me, I can't find that mystery part on my SS. Is it Frt lower-rear lower or frt top-rear top on the engine? connected to what?
Now I'm curious. "Moon":roll:

I know this may be slightly off topic, but do any of you know what part makes the turbo have that hiss sound. I believe it's the blow-off valve. Are there any aftermarket, or GM mods to improve the blow-off. Thanks y'all.:thumb:

Waaaay off topic. You should search the threads in this forum for BPV, BOV, blowoff valve, bypass valve, etc. Then read them.

If you look at the middle pic... you see the snorkel that goes between the airbox and the inner fender. The actual part is kind of hidden under the airbox at that point. I've wiggled it forward to take the pics. The piece is, from a connection standpoint, a vacuum tee. The leg of the tee is the one that (on mine) is vented to atmosphere. The right arm runs back toward the turbo... I think it's feeding the BPV vac/boost. The left arm runs down toward the front of the motor and is picking up boost near the MAP sensor on the IC pipe as it runs to the intake.