Spooledup300z

I always wondered that.. i know with Mass Flow, when u start getting into big HP figs u need to mod it cause it cant keep up.. but thats all i know.. and ie: us Z owners when we max our Mass out.. we can upgrade it but most go with the SDS system


and with Map sensor, or Speed Density.. what are the pros and cons about it?

mazdaspeed7

MAF sensors give the engine a signal telling how much air the engine really is taking in. This makes the engine adapt to changes in airflow requirements easily and effictively. But you have to have the sensor in the airstream, which can affect airflow, sometimes a lot due to the design of the MAF(like the POS one Mazda used on FC's) It also allows a slower, less complicated ECU since it doesnt have to calculate the airflow, it has a sensor that tells it that.

Speed Density does not use a MAF. It uses a MAP sensor(manifold pressure) and the engine rpm to calculate how much air the engine is taking in. The computer has no way of knowing when the airflow changes though, since it never actually measures airflow. Take Hondas for example. You can have a Honda with I/H/E, put a fuel pressure riser on it, and gain as much as 10 hp. Thats gaining back hp that was lost from the mixture leaning out due to more air being drawn into the engine that the ECU thinks there is. But speed density also has a few advantages. Its much more accurate on turbo cars n/c they have positive manifold pressure, and a MAF isnt as effective as calculating airflow in relation to boost pressure. You also have the advantage of nothing in the way of the airstream, and vacuum leaks have much less effect on the engine.

And programable ECU's are as good as it gets. You get the advantages of speed density, and you can program it to account for mods.

Spooledup300z

Adam.. damn dude thanx alot man.. u hit that **** right on the tit.. thanx