| I wanted to add to this regarding the blowthrough setup and my experience with it. There are very clearly notable benefits to this arrangement that I want to point out. 1) There are no idle/low load stumbling issues whatsoever. In a dual intake configuration with the N62 MAS units up front, there is a very small quantity of air volume moving through the sensors at idle and low load cruising condition (>30MPH). These sensors are incredibly sensitive to small changes in flow and even small gusts of wind passing across the filters destabilize the smooth flow of air through the sensors, disrupting the metering and causing the ECU to throw rather wide ranges of fuel delivery corresponding to these flow disruptions. This results in the engine idle bobbling around and in the extreme case, can actually cause the engine to stall. While cruising at low load, again, the same problem occurs as the air is flowing in through the fascia and turbulating as it diffuses into the frontal cavity behind the bumper. This causes the car to have a distinctive bobble in engine power output and you feel it as small decererations of the car and hear it as drivetrain lash. A lot of this can be minimized with the "pot mod" I came up with years ago to baffle the frontal area of the filters and reduce the turbulent flow through the meters. Since the blowthrough sensors are much further downstream in the system they are no subject to these effects at all. No more hesitation, perfectly smooth idle even in the worst of air gusting situations. 2) Fuel metering with BOVs is no longer an issue. The BOVs are placed (properly) upstream of the intecoolers in our 2.5" charge pipe kit so as to reduce additional hot air heatsoak of the ICs during a BOV event. Additionally, the turbos not having to also blow through the ICs produces less "backpressure" to the flow and thus reduces the amount of spooldown the turbos experience during a BOV event. In the original configuration with the N62 units up front, during a BOV event the ECU does dump a wad of additional fuel because the meters are telling it there's a lot of air moving into the engine. This amount of fuel dump is limited by a set of parameters within the ECU's programming so its not a flooding type of event, but it also makes adjustment of the BOVs a little more tricky to prevent the engine from wanting to stall out at the end of a BOV event if the engine is allowed to come all the way down to an idle speed. This blow-through MAS setup places the sensors downstream of the IC's, downstream of the BOVs, so they are accurately metering the air mass being consumed by the engine which prevents any of these issues from occurring. 3) Power to the wheels: This is actually notable by seat of pants believe it or not. The N62 MAS units are a flow restriction in the inlet system which causes the turbos to have to work harder; i.e. spin faster, to produce the same discharge pressure. This takes longer to reach higher spool speeds and also results in hotter air discharge temperatures. By placing the new blowthrough sensors into the charge side of the system where the density of the air is higher and more importantly, the velocity of the air is considerably slower, there are considerably less flow losses produced by this new configuration. 4) Installation and ease of fitment: As Jim pointed out already, the N62 meters are bulky and there's a lot left to be desired for fitment in the frontal area between the headlamps. Without the bulky sensors taking up so much room, it opens the opportunity for better filter placement as well as possibility for even higher flowing filters to be used. Aesthetically it is advantageous as the filters can be fitted higher up and out of sight through the front inlet of the fascia AND higher placed filters reduce the chance for hydrolocking to occur if someone so dared to even attempt driving through depths of water. Installation of these parts is painless as well. Not a whole lot of components have to be swapped out for this upgrade. The two new pipes behind the ICs where the sensors are located aren't difficult to access and the replacement of the driver's side throttlebody pipe to connect the air handling systems is also very easy to access and install. The Selin Translator is a nice compact component with clean mounting provisions and cabling is very easily routed to the sensors. It took a little bit of time to work out the specifics of how this system needed to be designed to work properly, how the plumbing needed to be arranged, Jim's work on having the sensors produced, etc, but the project came together very well with no surprises. I have been running this setup in my personal Z now for about a year and it has worked flawlessly. I literally have had to do nothing to it since it was put in place. No additional retuning was required either since the new sensors are calibrated to our custom tubing to directly perform as the N62 sensors do. From here forward, I wouldn't do it any other way. :)
Enthusiasts soon understand each other. --W. Irving.
Are you an enthusiast? If you are out to describe the truth, leave elegance to the
tailor.
Albert Einstein
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