i read that when you get any oil in the cylinder the chance of detonation increases, that being the case, why do i see so many people running the valve cover breather into the carb or intake of their efi systems? seems like the wrong thing to do especially on a high hp engine... rm

I agree I the car racing world we run valve cover breathers to a catch can or two. not back into the intake

I've been running mine into puke tanks for years, works great for me. but Not needed in every application. I don't have a huge amount of HP either.

Can we get some details on this fox body? Have 2 my self a 88 cupe and 89 hatch

427sbf, pt101, th400, holley dominator efi, made 1028rwhp on e85 and 18 psi. just a street car

I run a pan-e-vac system

Factory set ups usually do it to reduce emissions on cars. On a boat I guess it can reduce the chances of getting unwanted fumes.

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I have been using the Mann ProVent Air/Oil Separators for almost a decade on my Twin Screw Supercharger systems(and N/A engines too) with great success. Best separator I have found and during my Twin Screw development I tried pretty much all of them, including the more expensive aircraft separators.

The ProVents come in various sizes and were originally developed for Heavy Industrial Diesel applications (think very dirty diesel engines).

In our applications we plumb the return for the separated oil out of the Provent back to the oil pan via a one-way check valve so there is no need for a catch can to worry about. The separated air can be vented through a simple crankcase filter (open loop) or back through the intake system (closed loop).

Link to Mann ProVent PDF http://www.mann-hummel.com/fileadmin...nt_en_2013.pdf

You can see the ProVent in the pics below, note the round black device just to the left of center mounted to the backside of the radiator.

Cheers,

Dave

rm,i 100 % agree that it makes no sence to plumb an engines oil fumes to the carb,oil has a octain rating of zero.i guess some do it so they won,t smell fumes.