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It's not a good idea unless you're running a blow through AFM/MAF (after blowoff valve) or you have a standalone speed density setup. Otherwise, you are ejecting air that has been accounted for by the AFM/MAF, so you run excessively rich because the ECU thinks there is a lot more air going into the engine than there actually is. With a recirc valve, it re-routes the air before the turbo but after the AFM/MAF so it doesn't "double-count."
you can run a vent to atmosphere if youre either map/speed density ems, full stand alone ems or if you have a blow through maf where the bov is before the maf sensor.
What if your using a map only based stand alone? What's a good bov to atmo for a 3.3l ?
Yeah that's fine, your MAP sensor is looking at the pressure in the manifold, it uses predefined lookup tables to calculate the air entering the engine each cycle (VE).
I heard someone make the argument that a recirc valve will get you slightly better spool because there air being ejected right before the cold side, but it really has to be negligible. Plus, atmospheric dump valves sound so much cooler...
I've run back to back tests, though the tests were done with a draw through maf setup, I could not tell the difference in spool between the two. Only bad thing running a vent to atmosphere bov is your run rich between shifts and of your ISV is faulty it'll cause your car to stall. Call me a ricer and whatnot but I like the sound and it's part of the reason I converted to blow through maf setup. Throttle response is a bit better but that could be a placebo effect lol.
Originally Posted by odonnell
Yeah that's fine, your MAP sensor is looking at the pressure in the manifold, it uses predefined lookup tables to calculate the air entering the engine each cycle (VE).
I heard someone make the argument that a recirc valve will get you slightly better spool because there air being ejected right before the cold side, but it really has to be negligible. Plus, atmospheric dump valves sound so much cooler...
I heard someone make the argument that a recirc valve will get you slightly better spool because there air being ejected right before the cold side, but it really has to be negligible. Plus, atmospheric dump valves sound so much cooler...
thats really what I'm asking. I see on most map based race cars they use a bov. but if recirc is actually better throttle response, then why?
I also am looking for opinions on which bov? i.e. are the tial's good? any that are more adjustable than others?
05-04-2016, 11:01 PM
