93 replies to this topic

[Sutol]

I'm still not entirely sure i understand why it needs to be bigger, Is it to reduce flow rate?

resistance overall

but that still doesn't make much sense to me. its open, there is no resistance.

James, imagine blowing through straw and then blowing through a hose pipe, what's going to be easier?

Depends on the bore. Makes no odds on the length as long as there are no kinks or restrictions.

Mine as is Nick's runs over the subframe and out of the rear clam behind the rear wheel.

no length has a lot to do with it, as in a lot of cases Resistance in a pipe run is dependant on the velocity of the gases going through it, internal roughness and bends, changes in section etc. as well as length. I think Vocky's mod of increasing the vent bore is valid and should reduce back pressure in the crankcase.

[techieboy]

how often do you change your oil Matt?

3 or 4 times a year depending on how many trackdays I've done.

[Sutol]

how often do you change your oil Matt?

3 or 4 times a year depending on how many trackdays I've done.

so would i be right in saying every 3k miles or less? If so i think that this is probably about right to minimise sludging of the oil due to +ve crankcase pressures, which is what i believe happens on our SCed engines.

I'm just applying my own logic and experience to this thread and i'm quite open to be knocked down and put in my place. Much that I think the SC mod is very worthwhile this aspect of it hasn't imo been thought through. As said though Vocky's increase in vent bore seems logical and shouldn't be detrimental.

[techieboy]

so would i be right in saying every 3k miles or less?

Usually much less. The Le Mans trackdays and associated journey there and back is probably the longest it goes, mileage wise, between changes.

[MartinS]

The pipe I used is the same bore as was on there. Martin s

[Mike (Cliffie)]

But Chris, I don't have any issues. We are better off running a 10W50 oil and that will cure most of the heavy breathing. 0w is just too thin. Mine has pretty much stopped since I started running a Lucas Oil with a stabilizer added.

[Sutol]

I'm using 15w50 and I'm still getting Blowby. The car has forged after market pistons which by all accounts can lead to greater blowby. My issue is with over pressurising the crankcase which is not good as you know. From what Vocky and others have has said in this thread, the bore of the existing breather is on the small size. Adding length to the pipe will increase it's resistance to venting the blowby.

Edited by Sutol, 16 April 2012 - 07:57 AM.

[JimmyJamJerusalem]

Someone's going to have to draw me a picture Where does this pipe come from at the moment.....?

[Mike (Cliffie)]

Its the one that comes out of the cam cover. Surely the best thing to do would be vent the crankcase then Chris.

[NickB787]

Its the one that comes out of the cam cover.

Surely the best thing to do would be vent the crankcase then Chris.

interesting idea,

I have had no problems I change my oil every 3-4000, standard z head so maybe a larger size hole is an idea with the extra power now.

[The Batman]

Can't vent the crank on standard ecu as it throws a wobbly Venting it out the back is good aslong as you aren't following someone doing it as it spits crap out! It is also a mot failure

[Exmantaa]

Its the one that comes out of the cam cover.

Surely the best thing to do would be vent the crankcase then Chris.

Crankcase ventilation (the pipe on the LET engine) is done internally on the Z22SE. See the 6 vent holes in your cam cover/engine block.
They really should tackle the mapping for a proper working PCV system, but the vent pipe/hose should/must be enlarged for high boost/rpm use.
(And extra venting through the oil filler cap will omit the oil seperation baffles in the cover, so that may give a lot of oil consumption...0

[NickB787]

Off with the cam cover then or better still mod my spare one

[JG]

Jimmy,

We're talking about the pipe here that leaves the rocker cover here


And in the far right of this picture you can see it tied to subframe making its way down to the difuser.

[NickB787]

yep anyone got any pictures of their mods?

[Sticky]

Here's my effort. Apologies for the hole in the top of the oil filler cap, that was an earlier effort.

http://www.vx220.org...x-cam-breather/

Not sure how to post directly from the gallery.

[smiley]

I like that concept sticky.
Going to hunt for a spare oil cap.

[Exmantaa]

^^ That mod probably bypasses most of the oil separator baffles in the cover. Better enlarge the standard opening to a bigger size...

Edit: some pics of what is inside the cam cover baffle plate:
http://www.j-body.or...09&t=185338&p=1

Edited by Exmantaa, 07 May 2012 - 03:14 PM.

[Sticky]

And the problem with that is?

[Sutol]

Nothing if you want to increase oil loss and have oil dripping out into your engine bay. The only real way is to increase the bore of the existing breather imo.