Quick Procharger Race Bypass Valve Question ...

[Tim_in_NC]

This thing is supposed to stay completely closed at idle and light rpms ... right?

And then it should open after heavier throttle and then deceleration ...

Correct?

I've been driving the car around some just checking everything out but haven't really been gettin' on her ... I still haven't heard this thing open ... but maybe the car is just too loud ... haha

Thanks,
TIM

[camcojb]

This thing is supposed to stay completely closed at idle and light rpms ... right?

And then it should open after heavier throttle and then deceleration ...

Correct?

I've been driving the car around some just checking everything out but haven't really been gettin' on her ... I still haven't heard this thing open ... but maybe the car is just too loud ... haha

Thanks,
TIM
they are adjustable, but they stay open any time they're under enough vacuum, like at idle or shutting the throttle down after boost.....At least that's how mine was. I've seen guys adjust them to be closed at idle, but I don't think that's how they're intended to be.

Since it was open at idle you could hear it, but when it opens on throttle closing it'd be real tough to hear over the engine and moving car noise.

Jody

[gkring]

Don't confuse a bypass valve with a blowoff valve. the bypass you are running functions as a blowoff when you let out of the throttle, but also functions as a bypass under idle and light load where the blower is moving more air than you need. when you make it close at idle you theoretically will see vacuumn on the engine side of the throttle plates and boost on the blower side. just makes life a little harder on the blower and can cause compressor surge and driveability issues. On airflow meeter style setups you normally dump back into the inlet of the blower after the MAF sensor. That way it stays quiet and all air gets accounted for. On MAP based systems you can just vent to atmosphere like yours is doing.

[Tim_in_NC]

So, if the car is at idle, I should be able to feel air coming out of the bottom of the bypass ... correct ...

Then it closes as pressure is made and then opens again when throttle or pressure is released ...

I just don't understand why I'm not hearing this thing ... From what I listened to online, they seem pretty noisy ...

I have the vacuum port connected to the intake port ...

[camcojb]

So, if the car is at idle, I should be able to feel air coming out of the bottom of the bypass ... correct ...

Then it closes as pressure is made and then opens again when throttle or pressure is released ...

I just don't understand why I'm not hearing this thing ... From what I listened to online, they seem pretty noisy ...

I have the vacuum port connected to the intake port ...
have you tried adjusting it? This is the open red valve, not the enclosed one, right?

Jody

[Tim_in_NC]

have you tried adjusting it?

Jody

I did try adjusting is some last night but didn't really notice any difference in sound ... I'll play with it some more later tonight ...

At idle, I should feel air coming out of the bottom of the bypass, right?

Thanks

[camcojb]

I did try adjusting is some last night but didn't really notice any difference in sound ... I'll play with it some more later tonight ...

At idle, I should feel air coming out of the bottom of the bypass, right?

Thanks
which valve exactly do you have? The race enclosed one would likely muffle the sound. The red open one has slots all around the perimeter, and when idling you'll physically see the valve sucked into the housing and feel/hear the air coming out. It's a different sound than a blowoff valve, but you definitely hear air rushing out.

You can unplug the vacuum line and put a handheld vacuum pump on the valve and it should open completely. My guess is your vacuum is too low for the adjustment and spring pressure of the valve, and adjusting it should fix it. Just back off the adjusting screw with it idling until the valve opens (I think it's backing off, otherwise try the other way).

Jody

[Tim_in_NC]

which valve exactly do you have? The race enclosed one would likely muffle the sound. The red open one has slots all around the perimeter, and when idling you'll physically see the valve sucked into the housing and feel/hear the air coming out. It's a different sound than a blowoff valve, but you definitely hear air rushing out.

You can unplug the vacuum line and put a handheld vacuum pump on the valve and it should open completely. My guess is your vacuum is too low for the adjustment and spring pressure of the valve, and adjusting it should fix it. Just back off the adjusting screw with it idling until the valve opens (I think it's backing off, otherwise try the other way).

Jody

I have the enclosed version Jody ...

https://static1.pt-content.com/images/pt/2009/07/engineviewstraight-1.jpg

[camcojb]

nice setup Tim.......... :1st: Yes, the valve isn't opened and will need adjusting if you don't feel air rushing out that round port on the bottom........... how much vacuum do you have at idle?

[Tim_in_NC]

nice setup Tim.......... :1st: Yes, the valve isn't opened and will need adjusting if you don't feel air rushing out that round port on the bottom........... how much vacuum do you have at idle?

Finally got to check it all out this weekend ...

The valve must be working because air is pouring out of the outlet and the vacuum side of my vacuum/boost gauge is reading 15 ...

[camcojb]

Finally got to check it all out this weekend ...

The valve must be working because air is pouring out of the outlet and the vacuum side of my vacuum/boost gauge is reading 15 ...
perfect.......... :)

Jody

[4086D9]

Nice set up! Mine is pretty similar but planning to keep the boost down in the 7-8 psi range with this shortblock. Have you have a chance to hit the dyno yet?? Whats the whole combo??

[ryfrat]

Did you buy the setup from Scott or just his carb hat?I bought a setup from him over the summer and he was out of his carb hats.

[Tim_in_NC]

Did you buy the setup from Scott or just his carb hat?I bought a setup from him over the summer and he was out of his carb hats.

Sorry I've been away so long ... but yes this was a setup that I purchased from Scott ... Tensioner, Blower, Carb, Hat, Fuel System, etc ...