I asked the same question on the msextra forums, 
  
this is the solution 
  
  
Re: TunerStudio + BoostGauge, how to do it ? 
  
If you paste this into the custom.ini file in the projectCfg folder: 
  
 
Code: Select all
   [OutputChannels]
   vacuum = {(barometer-map)*0.2953007} ; Calculate vacuum in in-Hg.
   boost = {map < barometer ? 0.0 : (map-barometer)*0.1450377} ; Calculate boost in PSIG.
   [GaugeConfigurations]
   ; Name Var Title Units Lo Hi LoD LoW HiW HiD vd ld
   vacuumGauge = vacuum, "Engine Vacuum", "in-HG", 0, 30, 0, 0, 30, 30, 1, 1
   boostgauge = boost, "Engine Boost", "PSIG", 0, 20, 0, 0, 15, 20, 1, 1
 
  
It should be listed as "Engine Boost - boostgauge" under "Gauge Templates X" when you right click on a gauge 
  
thanks to Phil for the answer 
  
Nigel