The crank is always pressurised however when you are on boost this increases, therefore more pressure than an na. Normally this breather connects to the engine side of the throttle which in general is always below atmospheric pressure. On boost this goes into positive preasure which could be too high to allow the crank to vent via the inlet tract. You will therefore end up venting the easiest way possible which would probably be out of the rocker cover.
To avoid this you MUST connect the crank breather to a non positive pressure system, to the airfilter is ideal, however again the PCV is designed for an NA so you may get more oil being chucked up (it happens on an NA as well but most people don't care bout the tiny amount of oil deposits). You also need to take care of the increased pressure that will be in the rocker cover. Normally that is connected to the airfilter. If you don't mind oil in your inlet then go ahead however I recommend an oil sep. My oil sep has no oil return, I just empty it every year or so. It's a good indication how much oil I need to put back in! Matthew On 8 Feb 2012, at 15:57, nigelp <[email protected]> wrote: > The bit thats puzzling me, and I tend to agree with your reasoning > Matt, is that the positive pressure is prevalent in all the crank > area, not just the breather, so wherever I return to there is going to > be positive pressure trying to blow the oil back, including below the > oil level. As the crank ventilation 'box' has a return to sump side > to it and the cross sectional area of the opening is 3.1sq cm vs 1.327 > sq cm for a 13mm return line from turbo, it surely should take the > flow OK. The only bit I am puzzling over is the internal construction > and shape of the crankcase vent 'box.' Has anyone ever ripped one of > these apart or have a drawing?? > > I don't understand what you mean by this statement 'You also need to > take the crank breather back BEFORE the turbo not after.' Perhaps I'm > missing something. > > Thanks for all the inputs - intend to sort it this weekend. The > meassge is seeming like 'cover all bases.'' > > Nigel > > -- > You received this message because you are subscribed to the Google Groups > "Quantum Owners Group" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/quantumowners?hl=en > > IMPORTANT NOTE: All information presented herewith is provided on an "As Is" > basis, without warranty or the implication thereof. Neither the Quantum > Owners Club nor the individuals associated with the Quantum Owners Club or in > the preparation of the above information shall have any liability to any > person or entity with respect to liability, loss, or damage caused or alleged > to be caused directly or indirectly by the instructions contained within this > or related message(s). -- You received this message because you are subscribed to the Google Groups "Quantum Owners Group" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/quantumowners?hl=en IMPORTANT NOTE: All information presented herewith is provided on an "As Is" basis, without warranty or the implication thereof. Neither the Quantum Owners Club nor the individuals associated with the Quantum Owners Club or in the preparation of the above information shall have any liability to any person or entity with respect to liability, loss, or damage caused or alleged to be caused directly or indirectly by the instructions contained within this or related message(s).
