Ok under the the enhanced I/Os theres 4 0-5v inputs, obviously one is used for the wideband currently however the car in question is a turbo 02 ecotec running port fueler. So its using the OEM 1 bar for purposes of pleasing the stock PCM. Being that it as port fueler theres ZERO need to wire in the 2.5TMAP sensor. I want to use that TMAP to log boost in HP tuners, there are currently formulas in HPT for GM 1 and 2 bar, I need the formula for a 2.5 bar.
These are the formulas for 1 and 2, 2.5 should look similar to this but I am unable to find it anywhere
1 Bar MAP - GM: result = volts / .0533 + 10.354
2 Bar MAP - GM: result = volts / .02517 + 9
Basically we are going to hook the ground up, power the sensor with 5v and then wire the map 5v signal into the HPT enhanced I/O port just as the wideband is and then convert kpa into boost on the guage in HPT scanner, this will provide me with being able to see what boost range we are working with at a particular point so I can then make adjustments in port fueler with that programs software
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
If it's a GM 2.5 bar sensor try :
Result (kPa) = volts / .02 + 10
or
Result (kPa) = volts / .02
Conversion factors ~
1 bar = 100kPa
101.3 kPa = 14.69psi
And~
a 2.5 bar sensor can read about 21psi boost.
The first formula should put you close (as voltage x 50 = MAP in kPa). I searched a little online and could not find a slope/offset for the 2.5 bar. Using that formula, 0V is 1bar vacuum, and 5v is 22 PSI boost.
What you could do to check is log raw voltage and MAP using the formula above on the 2.5 bar and see how that jives with the 1 bar vacuum readings. If all the readings are off by the same amount vs the 1-bar in vacuum, you need to adjust the offset. If they are off more at higher MAP on the 1-bar (less vacuum) you need to adjust the slope.
Hope that helps.
Attached (jpeg) was a similar offset (example) that i had to look at for my Greddy boost/vac gage to log it in hptuners. One line was purely theoretical while the other was based on the offset I was seeing at 0 gage pressure or atmospheric.
- Attachments
- offset.jpg (121k)
as soon as i get my m62 i would very much appriciate it if rodimus or oldskool could help me out with it!
please let me know guys! im willing to drive to PA
I suppose being somewhat close wouldnt be that bad, port fueler is only every 500 rpm and every .5 psi, so long as im within a half pound i can adjust the proper cell
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
