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Let's Talk about Check Valves....

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Old Aug 23, 2016 | 12:53 PM
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Default Let's Talk about Check Valves....

So, as you know I am going twin turbo. I plan to run a vacuum hose from the brake booster port on the intake to a vacuum block, then run all of the vacuum lines from there - including the brake booster. I hear some say yes you need check valves, and some say you don't.

Do I actually need check valves? If so, where?
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Old Aug 23, 2016 | 01:00 PM
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The brake boost on my car, which was turbo from the factory, has a check valve on it. It is essentially a PCV valve.
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Old Aug 23, 2016 | 01:00 PM
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The fitting that goes on the end of the hose and presses into the brake booster IS a check valve.
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Old Aug 23, 2016 | 02:30 PM
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yep- the fitting in the diaphragm is a check.

I do run a check instead of a PCV though.
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Old Aug 23, 2016 | 02:30 PM
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since I am having a single vacuum hose going to the vacuum block (then everything vacuum related going from there) should I place a check valve between the intake and the vacuum block?
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Old Aug 23, 2016 | 02:34 PM
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Originally Posted by Hardcoresoldier
since I am having a single vacuum hose going to the vacuum block (then everything vacuum related going from there) should I place a check valve between the intake and the vacuum block?
No because then your waste gate would never see positive pressure
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Old Aug 23, 2016 | 03:23 PM
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My booster did not come with one. I ran a check valve inline to the booster only.
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Old Aug 23, 2016 | 03:47 PM
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Originally Posted by MY_2K_Z
No because then your waste gate would never see positive pressure
the blend doors on my HVAC are vacuum operated. would all that positive pressure screw them up or should I put a check valve on just that?
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Old Aug 23, 2016 | 03:49 PM
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I run a ck valve, and oil sep, but only go from intake to PCV valve
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Old Aug 24, 2016 | 07:33 AM
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I'd consider splitting the vacuum system up. The HVAC needs a check valve, unless you like it switching to the defroster ducts every time you get under a load. There is a GM model (I want to say S10 or maybe Trailblazer, help me here guys) with a check valve on the brake booster that has a port for the HVAC. If you have cruise control, you also will want to check valve that. The others could be run off a good vacuum tree.
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Old Aug 24, 2016 | 01:02 PM
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not worried about cruise control, I am DBW. I was also told today that my HVAC already has a check valve in it so it looks like I won't need to add any.
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