Thanks, I'm going to invite Keith into this. For what its worth, I pulled those numbers off the net and obviously can't vouch for the reliability of the source, but it seems like whoever put them in that tuning forum knew what they were talking about. I have the 845 in my Jeep. I don't get great fuel efficiency, but that hasn't really changed much before or after the 845.
gmctd wrote:
I wasn't quite fininshed entering data - this is more complete - and thanks for your input - I needed that
1 Bar = 1 atmposphere, or ~14.696 mean Barometric pressure - I round off to 15psi to make calcs easier for me
437 MAP 20kpa = 2.9psi - 300kpa = 42.5psi
845 MAP 11kpa = 1.6psi - 307kpa = 44.5psi
456 MAP 50kpa = 7.5psi - 350kpa = 50.8psi
437 = 3bar x 15baro = 45psi max with low 20kpa min output = 0.4v, hi 300kpa max output = 4.65v
845 = 3bar x 15baro = 45psi max with low 11kpa min output = 0.25v, hi 307kpa max output = 4.75v so press and volts scaling has wider spread than 437 MAP
456 = 3.5bar x 15baro = 52.5psi max with low min greater than the 437, hi max greater than the 437, but lo-to-hi voltage spread is narrower at 0.5min to 4.50max
So, pressure scaling and voltage scaling varies amongst the various sensors
The 456 is not compatible with the KJ system - the 845 is more compatible but will effect efficiency so I would not substitute it - long as the 845 does not fail emissions testing, and does not DTC, I'd guess it won't cause much hassle in most states, but it would affect overall fuel economy -
GDE should give final ruling on this issue, since they setup the ECM program to comply with EPA mandates