Catch can flow restriction

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Catch can flow restriction

Post by rn240sx » Tue Sep 11, 2018 12:31 pm


So as you look at the black catch can above the fuel filter and to the left of the blue fuel press sensor, you see the left side of the catch can is the exit to a hose that runs under the car... no oil gets out because the catch can is oil separator ... to the right is the catch can inlet which i have a hose then to a 5/8 Y adaptor then the Y adaptor recieves crankcase pressure / blow by from the valve cover breather and the "modified" (straight thru fitting) pcv below, all hoses are 5/8 ... and all fittings are 5/8 ...
My question is do you think that Y adaptor poses any air flow restriction from the motor properly exhausting its crankcase pressure .... or do you think its ok ..??
98 240sx ka-t (Fully Built, Bullseye 60-1 turbo, 10psi, Emanage Blue)
2014 Hyundai Genesis Coupe 2.0T (daily driver, stock for now .... )
2012 Frontier V6, 4-door, 6ft bed (Daily Driver)
09 Ninja ZX-6R, Full exhaust, K&N pod filters
06 Suzuki Boulevard S40
2015 Hyundai Santa Fe 2.0T (Wife's Daily)

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Re: Catch can flow restriction

Post by tuzzio » Thu Sep 13, 2018 7:06 am

Start the car and put your hand over the PCV or VC breather. Ask your self if you really think that thing is restricting.

I don't believe so. A 5/8 line is a pretty good size line.

But geez, what a cluster ***** of awful looking hoses and fittings.

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Re: Catch can flow restriction

Post by flip240 » Mon Sep 17, 2018 8:39 pm

I also don't think there's much restriction, your setup should be fine. But I'm not a fan of vent to atmosphere PCV systems (but everyone does it), I'd rather see the PCV hooked up to the exhaust or intake to provide suction on the crankcase, but these are difficult to plumb imo.

Regardless, I also have my crankcase PCV changed to a striaght through fitting with a 3/8" hose going to a Evo PCV on a canister; the end goes back to an intake manifold vacuum source. My VC PCV goes to a canister then routed back to the intake before the turbo.

my semi-rigged setup
- Phil - Concord Gray S14 - 339 rwhp, 340 ft-tq @ 12psi
Daily driven turbocharged KA24 for 10 years and counting. 2004-2014
My setup: KA24DE-T

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