ELUD THS

is the catch can neccesary at all to utilize? how many people that are boosted use one??

Ri5e

i had one. got rid of it.

PrecisionH23a

its not neccessary, but it helps keep my engine from oil being sprayed all over the manifold as well as fire wall. i dont spray oil a lot, but after time it adds up. some engines differ when it comes to crankcase ventilation problems.

shadowdawn

I simply attached a hose to mine and pointed it downwards.... it hasn't spray much of anything ever.

sutrusu

i'm rocking the APC beather filter. and yes, i know this is bad for it. and no, i dont care.

rjardy

how is this bad?


Rob

sutrusu

the system needs pressure in order to work proporly, or something.

BLKCRX

ok seems like iv been doin it wrong my self.. then...
when i was running low boost 7psi i was running a filter off my valve cover.. just a small one..which used have a pipe going from the valve cover back into the intake piping...

now im planing on running from the valve cover a oil catch can.. and also from the back of the block off some valve.. forgot what its called..and then run a filter off the catch can....

but if i understand this... im better to run the value cover breather back into the intake system ? yeah ? or do i go.. valve clover.. catch can... intake system.. ?
PS now im plani on runnin 20 - 30psi


Regards James

downpipe

the valve cover intake is supposed to function as a fresh-air intake for the pcv system. the crankcase vapors are vented out the back of the block via the pcv valve, which opens when it senses vacuum from the manifold. the problem here is that all of that oily crap gets sucked into your intake manifold and into your motor, increasing the likelyhood for detonation to occur.

under boost it's a slightly different story...the pcv valve needs vacuum to open, so when the engine is boosting it closes. that means there is nowhere for the blow-by to go except out the valve cover intake. that it why peoeple find oil on their valve cover breathers, and also why you don't want to run a hose from the valve cover intake to the intake piping (pre-turbo). you could be sucking oily-vapor-blowby right through your whole system under boost when the pcv valve closes and forces the gases out the intake - certainly the worst time to be injesting oil!

some people have told me that you need vacuum to help suck out the crankcase vapors properly, some say they'll come out fine on their own anyway. as we see, that all changes under boost anyway since boost will force the pcv valve closed.

considering all these factors, the best application for FI is proabably:

valve cover breather---->(crankcase)-->stock accumulator----->no pcv valve----->catchcan----->breather (on end of catchcan, not connected the the intake at all)

the closed loop option woud be:

valve cover breather tube connected pre-turbo------> (crankcase)--->stock accumulator----->catchcan----->pcv valve------>intake manifold

the second option will still allow oily vapors back in, just less. (be sure to use a baffled catchcan, or fill an unbaffeled can w/ steel wool). but remember, under boost the pcv valve will still be closed, and unless you are using the valve cover breather you could still wind up with oily vapor in the intkae charge.

anyways, good luck with whatever option you choose.

greg

psileepR

so thats what that third line going into my intake was... thanks for the informative breakdown