LNF Pull Thru MAF vs Blow Thru MAF

[MarkTucker]

Alright so, today I just realized why I am having a hard time getting the car tuned nicely. I have a pull through MAF setup and also have a BOV that vents to atmosphere. So the air flow that the MAF is reading is not actually want is going into the motor at all times. So what I am looking for is what would be best? Converting to a blow through MAF setup, placing the MAF after the intercooler but before the throttle body(ZZP has a kit)? My BOV is before the intercooler. Or would it be better to just tune speed density? Is speed density good for this cars, power, driveability, fuel economy? And if it is better to convert it to blow through MAF, who has the best pipe kit for the 2009 Cobalt SS?
Thank you.

[MarkTucker]

And what is the best way to go about tuning this cars speed density? Just for the experience side of it. I would like to just set up a speed density tune for the car and if I find out it is best to go with the blow through MAF. I will do that when I get the part in. But in the mean time would like to experiment with the speed density tuning, for learning.

[Area47]

unplug the maf. unplug the evap. work over the maf correction table/ve table. SD tuning in a quick dirty way.

[MarkTucker]

So just use the Histogram MAF Correction, scan LT+ST Fuel Trims on LOAD vs RPM? Or AFR Error, scan Lambda on LOAD vs RPM? Which do I copy and paste special multiply by %? Or do paste special multiply by % -half?

[Area47]

don't worry about ltft. run stft copy and paste -% load vs rpm maf correct setup.

[MarkTucker]

How about the MAF Calibration? Do I need to adjust any or do I need to leave what I had changed when I was tuning on it? Or do I need to return it back to stock?

[Area47]

the main scaling table is not touched. It will not register actually as the maf is unplugged. You will have some very light throttle issues between cells right off idle, but the rest will be fine. At least on the couple that I have done. Outside of this. go slow with it and make sure to hit as many cells as possible before you start messing with the boost side of it.

[MarkTucker]

I am still breaking motor in still before going to high boost right now. So to be correct I am just wanting to try and hit all of the cells in the MAF Correction table(scanner datalogging stft)? And copy and paste by % the stft into the MAF correction table on editor? Do I continue to copy and paste until it gets the stft close to 0% as possible. I have noticed that when the car is just entering into closed loop when car warming up the fuel trims look really nice until I drive it and get it warmed up and the fuel trims start to pull a lot of fuel out so when I copy and paste average % into MAF Correction, the next cold start up it will be lean, until it gets warmed up again.

[Area47]

copy and paste special, -% . Wait till the engine is warmed up and in closed loop ready to go. Or else things will change, which you can see already.

[MarkTucker]

Alright, thank you very much for the help and advice.