HardcoreABN

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?

Smoove

Factory booster hose(from booster to back of intake), should be a one way check valve already. You should be able to blow thru one side, not the other.

https://www.google.com/search?q=brak...KeA9gQ_AUIBygC

HardcoreABN

will I need one going from the intake to the vacuum block?

TTBlueZ06

No check valves needed, the plastic fitting that enters the booster already has one. Everything else you want to see boost and vacuum...

HardcoreABN

will the boost mess with the blend doors and such since they are vacuum operated?

StatmanRN

Havent run into any problems without them on the AC or brakes.

Black8Banger

Which vacuum block are you looking at using? Where are you thinking of mounting it? I'm debating removing my washer fluid reservoir (my meth tank is in the trunk) and mounting the block in that area.

TTBlueZ06

A little warning about vacuum blocks, use a dedicated vacuum source such as the one on the side of the intake by the throttle body to operate your blow off valves and FPR. Ive seen goofy things happen with getting your vacuum down stream from a remote source.

BLOWNBLUEZ06@RKT Performance

Some of this might already be obvious, but it's better to say it all and let you pick and choose what information is needed rather than me make assumptions and leave information out. The brake booster already has a check valve, as does the vacuum operated items in the AC system. The blend doors are electric actuators. The level controls (windshield defrost to face vents to floor vents) are vacuum controlled.
Putting a check valve on your BOV's would hold them open indefinitely. Never put BOV's on any downstream vacuum sources. Give them a direct path with good quality, firm, purpose-based vacuum line so it doesn't collapse when vacuum hits it. The farther away the BOV's are from the vacuum source, the larger diameter line you should use.

HardcoreABN

Alrighty. So I am looking at the waste gates, brake booster, HVAC vacuum line, and boost controller / boost gauge from the vacuum block, and the FPR and BOV from a single common source.

The vacuum block will be supplied by the brake booster port on the back of the intake, and the FPR and BOV from the small vacuum nipple on the back of the intake.

I am planning to use 1/4" OD semi-rigid nylon tubing designed for use as air lines to plumb everything.

TTBlueZ06

What intake is on your car? I would supply the BOV with the vacuum port by the throttle body.. that little port on the back of the intake is insufficient...

TastyBacon

FWIW, I put a check valve between my intake manifold and evap solenoid, so there would be no chance of blowing boost out the evap line. I'm not sure that's actually necessary though (and everyone just deletes evap anyway, right?)

HardcoreABN

LS3 intake and LS7 throttle body