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Vaccum line sharing?

Posted: Tue Oct 04, 2011 6:45 pm
by rodney007
Can your BOV, boost gauge, fuel reg run off one vacuum line?

Posted: Tue Oct 04, 2011 8:50 pm
by Lummy
Tuners cringe a bit when you run multiple things off a single vacuum/boost line, but in theory, it's all good.

Some may argue it would create a delay to your boost gauge, but compressed air acts pretty quickly. I'd be happy to do it.

Ideally, you'd just tap a few new outlets to your inlet manifold and run a dedicated line for each purpose.

Posted: Wed Oct 05, 2011 12:28 pm
by rodney007
hmmn, well if I can find out if i need to run the PCV valve thingy from the cam cover I can use that .

Posted: Thu Oct 06, 2011 3:12 pm
by Entaran
The PCV valve on the cam cover isn't for vacuum broski. It is a vent for oil and will get gummy as fuck. You do NOT want that connected to anything you "like". It generally goes direct to a catch can.

Drill/tap a few new connections on your inlet manifold if you're fresh outta lines, while you're there - replace every vac line in your engine. It's cheap and they're probably old and feral by now anyway.

Posted: Sat Oct 08, 2011 10:17 am
by rodney007
well thankfully my dohc engine is new along with all my vacuum lines etc.

broski I heard PCV valve isn't just a breather like you say. it goes to your intake manifold,. and has a packing or stuffing inside (which i have seen) that restricts flow to aid oil pressure inside the engine,

then, your cam cover breather, goes to a catch can.

Posted: Sat Oct 15, 2011 6:57 am
by Lummy
Wow, to aid oil pressure?

The only oil pressure problems I have with my DOHC 4G63 is too much.

I don't know why it's so high, but I get 50-60psi at idle and over 120 on the gas.

My PCV is long gone and I just run lines direct to the catch can.

Posted: Sat Oct 15, 2011 4:30 pm
by enthuzed
Yeah I read that in an earlier post of yours Lummy, that's huge oil pressure!

Posted: Sun Oct 16, 2011 5:57 am
by OLD FART
rodney007 wrote:well thankfully my dohc engine is new along with all my vacuum lines etc.

broski I heard PCV valve isn't just a breather like you say. it goes to your intake manifold,. and has a packing or stuffing inside (which i have seen) that restricts flow to aid oil pressure inside the engine,.
The PCV has ABSOLUTELY NOTHING to do with the oil pressure.
In is a simple device fitted into the rocker cover that has a hose running to the IM that allows fumes to be drawn from the crankcase when the manifold is in vacuum=suction so they can be burnt during the combustion process but closes to seal the CC when positive pressure = boost occurs

Posted: Mon Oct 17, 2011 11:50 am
by Mick
^^^one way valve in the old money.

rodney have you removed you balance shafts?
removing them ups oil pressure a bit.

Posted: Mon Oct 17, 2011 2:31 pm
by rodney007
so... should I run the pcv line straight to intake manifold? or two lines to my catch tank instead?

ideas?

Posted: Mon Oct 17, 2011 4:21 pm
by fugazi
IF you'r using the PCV run it to the mani, AND some lines to a catchtank/can!

Posted: Tue Oct 18, 2011 11:18 am
by Alspos
PCV runs straight into the inlet manifold, under the throttle butterfly.
Catch can is different part of the system, it should run back into the inlet tract, normally just after the air filter. If you connect the two systems, the catch can will become pressurized/vacuum by the PCV system.

Posted: Tue Oct 18, 2011 6:46 pm
by rodney007
ok thanks guys

Posted: Wed Nov 02, 2011 9:52 am
by JAS
Ive got a vacum distributor in my brake booster line.
Its a nice size hose with a bit of volume. Fine for a BOV and boost gauge etc. Id use a separate vac line straight form the manifold for the fuel reg though.