For those not using HP Tuners.
Disclaimer here not that it will really matter to anyone here because I doubt their engine moves enough airflow for it to matter. The BlackBox has a 400 gms/sec limit, which the stock MAF curve reaches at a little less than the highest 11,000 hz entry. From 10,875, the MAF curve is a linear extrapolation from the trend of the data between the GMT400 and Express van. The last 3-4 entries before that were a 5.2% difference between GMT400 and Express. I thus multiplied the Express van entries starting at 11,000 hz through 12,000 hz and multiplied them by 1.052 and allowed HPT software to cap the value at its highest value of 511.992 for the last two entries. Not like any L31 truck is really going to run up there anyway. Most are not going to break 300 gms/sec much less 400 gms/sec. 1 gm/sec is pretty close to 1.2 hp at the crank or 1 hp at the wheels. Thus rough math, a truck moving 300 gms/sec is making about 360 crank hp or 300 wheel HP.
MAF HZ and Flow GM/Sec
1,500---2.508
1,625---2.898
1,750---3.367
1,875---3.859
2,000---4.422
2,125---5.039
2,250---5.734
2,375---6.508
2,500---7.336
2,625---8.211
2,750---9.180
2,875---10.203
3,000---11.289
3,125---12.445
3,250---13.680
3,375---15.023
3,500---16.438
3,625---18.008
3,750---19.680
3,875---21.430
4,000---23.297
4,125---25.289
4,250---27.367
4,375---29.555
4,500---31.852
4,625---34.234
4,750---36.727
4,875---37.695
5,000---40.375
5,125---43.195
5,250---46.180
5,375---49.313
5,500---52.609
5,625---56.102
5,750---59.781
5,875---63.641
6,000---67.672
6,125---71.867
6,250---76.250
6,375---80.773
6,500---85.477
6,625---90.313
6,750---95.336
6,875---100.539
7,000---105.930
7,125---111.516
7,250---117.281
7,375---123.227
7,500---129.367
7,625----135.703
7,750----142.234
7,875----148.922
8,000----155.898
8,125----163.102
8,250----170.516
8,375----178.117
8,500----186.094
8,750----202.875
8,875----211.688
9,000----220.805
9,125----230.234
9,250----239.969
9,375----250.016
9,500----260.367
9,625----271.063
9,750----282.063
9,875----293.398
10,000---305.055
10,125---317.039
10,250---329.367
10,375---342.000
10,500---354.969
10,625---368.266
10,750---381.875
10,875---395.797
End of GMT400 Factory MAF Data
Start of extrapolated data
11,000---409.523---cut to 400 in the blackbox
11,125---424.109
11,250---439.039
11,375---454.313
11,500---469.922
11,625---485.875
11,750---502.148
11,875---511.992
12,000---511.992