running a B.O.V vented to the atmosphere?

Discussion in 'Fox 5.0 Mustang Tech' started by qwikstik, Jan 31, 2012.


  1. qwikstik

    qwikstik New Member

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    Currently I have a Mondo bypass valve that is recirculated back into the system on my car, but I was looking into running a b.o.v or a diverter valve that uses what they call an "anti stall" valve that will allow MAF cars to vent to the atmosphere without having issues. The MAF sensor is set up as a draw through configuration. Does anyone have any info or experience with this setup I am looking into, or am I wasting my time? The reason for doing this is I would rather sell my Mondo (make decent money off of it) and buy something that I could vent into the atmosphere as opposed to having to route back into the system. Any info would be cool.
  2. 88lxnotch

    88lxnotch New Member

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    The MAF meter tells the computer how much air is going into the engine. If you let air out by having the blow off valve after the MAF, the air/fuel ratio will be wrong (you'll be rich). If you use a bypass valve and vent the high pressure air back behind the MAF, the air still stays in the system and everything is OK. The OEM's use this approach on boosted cars because it is quiet.

    If you want a blow off valve, convert your system to a blow through MAF. As long as you have the blow off valve before the MAF, it will be OK. The MAF will read air going into the engine after the valve and after the high pressure air has been vented.


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  3. Rick 91GT

    Rick 91GT SN Certified Technician Site Sponsor

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    Are you using a stock EEC or a aftermarket system? What MAF is it? Were you looking at the large red Procharger valve?
  4. 88lxnotch

    88lxnotch New Member

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    Good point. An aftermarket system like a FAST or Accel DFI doesn't have a MAF meter, all that matters is engine speed, manifold pressure and air temperature. You can vent however you would like in that case.

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