Vac u pan and fuel air sensor

[steve cowan]

Hi guys,
Probably a loaded question
Can the fumes coming through a vac u pan at the collector effect air/ fuel reading at the sensor ??
I can get a set of pipes for my car same size as I have but with a evac at the collector
I have the auto meter air/ fuel sensors in the exhaust approx 12 inches past the collector
At the moment I have breathers from rocker covers baffled and going through a moroso catchcan and venting to atmosphere
I would like set up a vac u pan through oil separators,I don't know if it worth any power or not
If the general consensus is it is worth the effort I would spend the extra time taking the breather from the intake manifold instead of rocker covers,my main question is about the sensors becoming contaminated or incorrect readings due to wind age gases
Again probably a loaded question but I am interested in everyone's advice and opinions
Thanks,
Steve c

[cjperformance]

Yes, vac u pans most definetly do affect the reading at a/f,,o2 sensors. V8? Vac u pan/s in one side, o2 in the other. Pulling from the valley in many engines will aide head oil return so in these cases its a plus provided there is adequate crank case to valley ventilation.

[MadBill]

Blowby is a mixture of air, fuel, oil and exhaust, varying through strokes and operating condition, thus it's pretty well impossible to predict its effect on AFR. Hooking up only one bank will reduce the already sub-optimal pan vac.
If you optimized AFR without the exhaust vacuum, then hooked it up and noted the new values (or ranges of same) you'd at least have a ballpark number for future reference. (A pan vacuum gauge would alert you to cylinder sealing problems.)

[F-BIRD'88]

On a street driven car you don't really want crank case vacuum,,, you want crank case "Ventilation" "PCV" .. You get across the engine crank case ventilation by venting one valve cover and hooking up the pan evac to the other opposing valve cover.
You could have both Ventilation for driving and PAN evac, crank case vacuum for WOT,,, tru use of flow control valving check valves etc.
Yup a pan evac in the header will effect the AFR of the O2 sensor in that header.
Either way if you don;t have good oil control baffling in the vents you are going to get engine oil loss, oil soaked under body, and more...
A pure drag racing type Pan e vac system may not be your best path on a street driven car.

[MadBill]

Not to mention it takes a very good vac system and low back pressure mufflers to work at all on the street..