Mass Air versus Speed Density

[Ed Wright]

Originally Posted by LNorton

The main deal is that sometimes this thing seems to have a mind of its own.

I have been looking at Simple Digital Systems (SDS) and MegaSquirt. The factory PCM just has way too many variables that I can not get to with HP Tuners. Have also talked to a lot of guys running the stock PCM and none of us can find a solution to turn the thing past 6400. All of our factory tables end there, and no matter what we try it will just flat line.

I know that Speed Density wont exactly make the car more consistent, but from a tuning perspective will it be easier to deal with than Mass Air?

Also, have you guys dealt with stock PCMs?

If you change systems, I would (and do) use FAST myself. Holley is very popular, but I'm not crazy about it. Big Stuff3 is pretty popular, but I haven't worked with it as much as the FAST. Sems to be a very good system. The aftermarlet systems I have dealt with don't use a MAF. I tune GM vehicles all day, every day, with factory computers. That's how I make my living. Most GM PCMs (computers) will run past the RPM for last row in the tables, but you can't make tuning changes past that. The factory LT1 boxes' tables extend past 7000, but the injector drivers give up there. It sounds like the rev limiter when you hit that point. The '96/2000 Vortec truck (old body style) boxes won't run past 5500 or so, even though the tables go higher.

Good luck, Ed