Catch can question..which is better? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

nevaland9 · 08-06-2007, 03:53 PM

Ive heard better vac helps seals the rings better and makes the motor happier but which was is the best? Just putting a breather on dosnt seem too smart.

Which way is the best way to run my catch can and why?

this way looks the easiest.

and theres this way

i heard this way is the best

help me out

DJ_Sunrise · 08-06-2007, 05:32 PM

When I get mine, Im going to mount it on the drivers frame rail, that way it doesn't clutter up the engine bay.. Some guys just run a line straight through with no can.. but that makes the underside messy

Just an idea.

-Bart

SlowCoupe · 08-06-2007, 05:36 PM

i think the 3rd way is best.

thats assuming the line comming off the tee goes to a can and a line from the can goes to the turbo intake.

thats how i have mine hooked up.

smelly240 · 08-06-2007, 06:17 PM

mines the 3rd way...

jilo · 08-06-2007, 07:58 PM

on a redtop or basically any other sr it should be a line from crank case->catchcan->t->post maf intake

1320_power · 08-08-2007, 01:21 AM

quoted from a friend in japan

here is one hose that goes from the valve cover to the intake manifold with a check valve in place called a PCV valve, positive crank ventilation. Basically this sucks the pressure out of the crank case when not under boost. When under boost, boost pressure closes the PCV valve. If this valve was not there and it was a direct hose, then it would over pressurize the crank case.

Then thee is another hose that goes from the valve cover to the intake pipe of the turbo. When under boost, the turbo creates a vacuum in front of the compressor inlet, sucking the pressure out of the crank case.

At high RPM is when you get the most blow by and crank case pressure. When there is no catch can where from the valve cover to the turbo intake pipe, oil along with air get sucked out of the crank case. This oil gets sucked right into the turbo and makes it way to the intercooler. So to alleviate this, a catch can is installed.

The hose goes from the valve cover, to the catch can. Then another hose goes from the catch can to the turbo intake pipe for the vacuum effect. So at high boost high rpm, the catch also has a vacuum.

The other fitting I would say its for draining the catch can. Its not necessary to have the vacuum effect for crank ventilation. but that more for people who do not run intake pipes on their turbo., or a PCV valve on their intake manifold. The hoses just dump to the atmosphere.

08-06-2007, 03:53 PM	#1
nevaland9 Zilvia FREAK! Join Date: Sep 2004 Location: Long Island, New York/Toronto, Canada Posts: 1,251 Trader Rating: (0) Rides Gallery: nevaland9 Feedback Score: 0 reviews	Catch can question..which is better? Ive heard better vac helps seals the rings better and makes the motor happier but which was is the best? Just putting a breather on dosnt seem too smart. Which way is the best way to run my catch can and why? this way looks the easiest. and theres this way i heard this way is the best help me out __________________ CEO @ Sticky Garage 516-993-7315 -Jason Check out my warehouse!

08-06-2007, 05:36 PM	#3
SlowCoupe Zilvia Junkie Join Date: Feb 2004 Location: New Orleans Age: 39 Posts: 341 Trader Rating: (0) Feedback Score: 0 reviews	i think the 3rd way is best. thats assuming the line comming off the tee goes to a can and a line from the can goes to the turbo intake. thats how i have mine hooked up. __________________

08-06-2007, 06:17 PM	#4
smelly240 Nissanaholic! Join Date: Oct 2006 Location: Philaburbia Age: 46 Posts: 2,137 Trader Rating: (4) Feedback Score: 4 reviews	mines the 3rd way... __________________ HREs on a S13 - check, 6262 - check, Girlfriend.... - nope

08-06-2007, 07:58 PM	#5
jilo Zilvia Junkie Join Date: Jun 2006 Location: ct Posts: 312 Trader Rating: (2) Feedback Score: 2 reviews	on a redtop or basically any other sr it should be a line from crank case->catchcan->t->post maf intake __________________ "just throw in like 8 packs of BBs and do a burnout. DIY shot peen, done and done."

08-08-2007, 01:21 AM	#6
1320_power Join Date: Feb 2007 Location: japan Posts: 34 Trader Rating: (0) Feedback Score: 0 reviews	quoted from a friend in japan here is one hose that goes from the valve cover to the intake manifold with a check valve in place called a PCV valve, positive crank ventilation. Basically this sucks the pressure out of the crank case when not under boost. When under boost, boost pressure closes the PCV valve. If this valve was not there and it was a direct hose, then it would over pressurize the crank case. Then thee is another hose that goes from the valve cover to the intake pipe of the turbo. When under boost, the turbo creates a vacuum in front of the compressor inlet, sucking the pressure out of the crank case. At high RPM is when you get the most blow by and crank case pressure. When there is no catch can where from the valve cover to the turbo intake pipe, oil along with air get sucked out of the crank case. This oil gets sucked right into the turbo and makes it way to the intercooler. So to alleviate this, a catch can is installed. The hose goes from the valve cover, to the catch can. Then another hose goes from the catch can to the turbo intake pipe for the vacuum effect. So at high boost high rpm, the catch also has a vacuum. The other fitting I would say its for draining the catch can. Its not necessary to have the vacuum effect for crank ventilation. but that more for people who do not run intake pipes on their turbo., or a PCV valve on their intake manifold. The hoses just dump to the atmosphere. Last edited by 1320_power; 08-08-2007 at 01:24 AM.. Reason: mistake

08-06-2007, 05:32 PM	#2
DJ_Sunrise Zilvia FREAK! Join Date: Feb 2004 Location: NJ Age: 37 Posts: 1,134 Trader Rating: (1) Feedback Score: 1 reviews	When I get mine, Im going to mount it on the drivers frame rail, that way it doesn't clutter up the engine bay.. Some guys just run a line straight through with no can.. but that makes the underside messy Just an idea. -Bart