Any time the MAS is in front of the BOV, air is counted, which in turn, if it leaves the system (venting to atmosphere) means that counted air and the associated level of fuel provided by the ECU makes the car run extremely rich when the BOV opens and allows air out. That is how it works. The MAS counts air and when some of that air is lost, the ECU simply cannot figure that out and still adds the massive amount fo fuel for that air amount.

An AFC cannot indiscriminately be used to pull out fuel for "letting off the trottle" and for the throttle plate closing between shifts. It does not work that way. It's hard enough to tune a DSm as it is, so trying to use an AFC to tune for power and to pull fuel out at exact RPM ranges when you think you's "let off the gas" or when you'd shift is just impossible. You never know the exact RPM when you'd be closing the throttle plate (unless you are some kind of cyborg driving machine) so tuning for what you're trying to accomplish would be basically impossible.

The only way a DSM can vent appropriately is by converting to a MAP style system (VPC or full Standalone), or by putting the MAF after the BOV (GM MAF/MAFT). With a blow through style MAF set up, the ECU does not get input on how much air is coming into the intake manifold until after it has either gone past the BOV and either vented or not vented. Either way, the ECU is getting an accurate representation of the air amount. Simply put, an SAFC cannot fix the issue of venting, but a GM MAF and MAFT can. There are stockish pipes now that allow for a blow through MAF setup on the stock sidemount. Also, the GM MAF (3") flows about the same or maybe a hair more than the 2g MAS and the 3.5" one outflows it by a lot and really is unnecessary unless you are planning on making HUGE power numbers. The 3.75" LS6 MAF is for guys like Kurt Brown and John Shepherd.

Edit: See also http://forums.2gnt.com/dcboard.php?az=show_topic&forum=17&topic_id=11905&mesg_id=11905&listing_type=search

It's running again shitheads.

http://www.dsmregistry.com/detail.php?carid=791

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