pre-maf VCV inlet, oil contamination

[mikus]

I'm looking to put my car back to 'stock-style' ventilation (i've ran a few configurations)

I have a 3G MAF adapter (the off the shelf one, Spectre brand) that has a hose inlet that would be ideal for my valve cover vent to intake point. only hangup is that it's pre-MAF - so MAF contamination from oil/vapor is a concern. I will have an inline sealed catchcan.

I think 1) contamination would be minimal given the catchcan, and 2) I'd rather clean my MAF occasionally than drill my intake pipe...

also found this interesting K&N video on the topic of MAF contamination that makes me feel OK about it.

Thoughts?

 

[turbowop]

Any air that would be routed back into the intake has already been accounted for by the maf. Running that vent in front of it would make the maf count that air again, making it think it needs to add more fuel. Probably not by much but that's one issue besides the possible problems of oil contamination.

 

[atc250r]

Whether its directly before the MAS or out to atmosphere with a little filter of its own on the end the air is not being read either way so why not just let it vent to atmosphere. Besides, why would you want all that dirty oily air going back into your engine and gumming up your valves/intake manifold?

John

 

[turbowop]

*edit* Nevermind, I must be smoking crack. /ubbthreads/images/graemlins/crazy.gif

Either way, I just run both vents to a catchcan/breather on both my gvr4's. /ubbthreads/images/graemlins/smile.gif

 

[atc250r]

I do pretty much the same Mark. I actually have 3/8" barbed fittings where he PCV used to be and where the VC breather used to be. I had a catch can but I got tired of draining it and it also spewed a decent amount of oil out the breather so I just hooked two 3/8" lines to the fittings and ran them down between the front subframe and the firewall. They just vent to the road like cars used to do back in the 50's and early 60's.

John

 

[mikus]

^ how long have you guys run VTA?

I'm VTA now, but the position that a few hg of vacuum on your crankcase being beneficial (by evacuating corrosive gases) makes sense to me.

Thus I want to put my PCV back - if I do this, I need to 'close' the VCV system. Thus the question. The meter reading the air twice makes sense ^ as an issue with pre-MAS inlet though...