gameover00

I have a 02 Vortech supercharged mustang.. Im gettin around 8lbs of boost. I wanting to put a smaller pulley to get around 10lbs. My mass air peter is at 973 counts at 6000.. Would adding two more lbs of boost peg my mass air.. I think pegging is 1,023 counts.

cliffyk

In all probability, it's real close now--what MAF is it?

Out of curiosity what logging software are you using the reports MAF output in "points"...

gameover00

im useing a predator for the logging and i have a lightning 90mm maf

scott4.6

You said peter, lol.

cliffyk

The Lightning 90 mm (red curve below) pegs just at the 3838.2 lb/h (1741.38 kg/h) limit of the EECV PCM:



To go beyond that limitation you have to scale the MAF curve of the new MAF to keep the interpreted air flow under 3838.2 lb/h, and then reset the standard air charge and and injector slopes by the same factor.

For example if you were running the Bazooka 3000 MAF, which maxes out at 7026.2 lb/h, you would have to:

• scale the MAF Transfer Function by 3838.2/7026.2 or 0.5463 (54.63%);
  
  
• scale the Standard Air Charge (stock value is 0.0015531 lbmass of air) by the same amount, 0.0015531 * 0.5463 = 0.0008484 lbmass air;
  
  
• scale the Air Manifold Volume (stock value is 0.3399 ft³), 0.3399 * 0.5463 = 0.1857 ft³
  
  
• scale the Low Injector Slope (assume 60 lb/h injectors), 66.0 * 0.5463 = 36.06 lb/h;
  
  
• scale the High Injector Slope (assume 60 lb/h injectors), 60.00 * 0.5463 = 32.78 lb/h;
  
  
• scale the Injector Breakpoint (FRPP 60 lb/h value is 21.4875 μlb/crank revolution), 21.4875 * 0.5463 = 11.7386 μlb/rev;

That's it, piece of cake...

gameover00

so are you saying if I adjust the slopes then the maf will be ok to use?

cliffyk

No, I am saying that the Lightning MAF is damned near pegged (the EECV PCM will only recognise up to 4.99V, 1023 counts, from the MAF). When the MAF does peg (reach 5.0V, 1023 counts), and the air flow rises much more) the AFR will suddenly go lean and in all likelihood detonation will kill the engine.

What you will need to do is get a higher capacity MAF, if you start ingesting more air--and then make the changes listed above to re-scale the tune.

To make those changes you will need a low-level tuning system like SCT Advantage or Delta Force Commando.

I know that an SCT handheld would let you load a scaled tune created with Advantage, however I do not know what sort of tweaking it would allow.

ShadowDrake

Good stuff! Gonna save this. I forgot that my FBFG2 strategy goes to 64 lb/min (3840 lb/hr)

Any idea what the specific PID is for Standard Air Charge is? I don't remember seeing that anywhere in my tune (albeit, my strategy file has -no- descriptions in it).

cliffyk

I am confused by your use of the term "PID" (Parameter ID), as PIDs are the OBD2 identifiers for requesting operational values from the tune via the OBD2 port.

In your FBFG2 strategy the Standard Air Charge is a unsigned Intel word at offset 0xE6DE. In some tuning systems it is called the "displacement of one cylinder" with the value being units of mass (English or metric) of air at STP.

In EEC Editor is is called cid_airmass_for_one_cyl...