Map Sensor Equation
Modeling the Map Sensor voltage output into a usable number. (From the Helm Manual:) !hondastockmapvolt.
Adapted from pgmfi.org wiki
Modeling the Map Sensor voltage output into a usable number. (From the Helm Manual:) 
y = mx + b y = mx + 2.85v y = (-.1)x + 2.85v (-.1)x = y - 2.85 ***x = (y - 2.85v) / (-.1)***Alldata publishes a MAP sensor spec, and I took data from my MAP sensor to compare, and added the data per the Helm-based formula:
05 in Hg| Alldata: 2.5 | 2.35 Helm-based formula | my actual: 2.460
10 in Hg| Alldata: 2.0 | 1.85 Helm-based formula | my actual: 1.938
15 in Hg| Alldata: 1.5 | 1.35 Helm-based formula | my actual: 1.509
20 in Hg| Alldata: 1.0 | 0.85 Helm-based formula | my actual: 1.012
25 in Hg| Alldata: 0.5 | 0.35 Helm-based formula | my actual: 0.558
Based on the Alldata spec, the formula is: ***x = (y - 3.0v)/(-.1)***It looks like these two formulas can give you a reasonable range for calibration. -- markolson - 04 Mar 2005
Credits and source
Authors blundar, markolson
Source Adapted from Map Sensor Equation on pgmfi.org wiki. Licensed under CC BY-NC-SA 1.0.