DieselMinded said:
So an Edge Comp with a $50 Anti Defueling Map is the Exact same as a Edge Comp with the $100 Drag Option .
Right ?
DM
Apples and oranges.
Apples:
The MAP sensor, or manifold absolute pressure sensor, measures the amount of boost pressure in the intake manifold. More pressure = more voltage output from the map. The ECM reads the voltage as pressure, and adds fuel accordingly. The ECM will not command any more fuel than the engine can burn with the observed pressure. As the turbo spools and pressure increases, then more fuel is added. But if the turbo generates too much boost (failed wastegate, increased power, etc. ) the ECM will read the high voltage output from the MAP sensor and it will try to protect itself from overboost. It does that by throttling back the fueling amount (same as letting off the throttle) which will decrease the drive pressure and therefore reduce boost pressure (and setting a code). That's defueling due to overboost.
The workaround that we use to bypass this self protect is to "clip", or reduce the voltage being sent to the ECM from the MAP sensor to something lower than the value that will trigger an overboost situation in the ECM. It's basically a resistor. That way the ECM never "sees" any more than 24psi (or whatever) and will not defuel. Most power enhancing boxes on the market will splice in line between the MAP and the ECM so the box can "read" the actual voltage to adjust fueling on their terms, and then send a lower signal to the ECM so it at least knows that boost is being generated, but it will never reach a value that would trigger an overboost. The Anti-Defueling MAP you mention is essentially a MAP sensor that will produce lower than stock voltages that will never exceed the overboost value. The ECM will never "see" more than 24 psi, and will not de-fuel due to an overboost condition. Putting a "clipped" MAP in front of a box may not allow the box to perform properly, since the box then isn't seeing actual pressure (and there would be no reason to do this, since the box is already clipping the signal).
Oranges:
If the engine maintained maximum fueling to redline in the factory configuration, egt's would go through the roof due to the small factory turbos. They just couldn't handle the exhaust volume created by the high engine RPM (remember, it's an air pump) and the expansion of gasses from heavy fueling. You would choke the turbo if you maintained maximum fueling. So the factory ECM starts to decrease the amount of available fueling after 2700 rpm. This reduces potential high egts at high rpms due to turbo choke. It's like a moveable throttle stop that starts pushing back on the pedal after 2700 rpm (but electronically). Then once you hit 3200 rpm, the ECM will roll back the fueling to whatever it takes to maintain 3200 rpm.
The standard Comp will follow the factory fuel curve above 2700 rpm, meaning it will start rolling back fuel, thus decreasing power. When the Drag Comp (on 5x5) reaches 2700 rpm, it holds up both middle fingers to the ECM and will still command maximum fueling all the way to redline. So the truck with the Drag Comp will continue to pull hard above 2700 rpm, while trucks with the standard Comp start to loose power. But in either case, once the truck hits 3200 rpm the redline governor kicks in and will keep the rpm at 3200 rpm, regardless of what version you have.
In a nutshell, the anti defueling MAP is to prevent the ECM from defueling due to overboost ONLY. If you alread have a box in place that does this, adding the anti defueling MAP is a waste. It's redundant. It has nothing to do with de-fueling in the higher rpms.
The Drag Comp squeezes a bit more fuel in on the top end for a bit more power above 2700 rpm, but still does nothing about the 3200 rpm redline.
Attention: TDR Forum Junkies 
