BOOST

[Power Hungry]

I've run up to 40 PSI on several trucks without any head gasket issues. The stock MAP sensor will only pull up to 24 PSI. This is due to the fact that they use a 3-bar MAP, but 1 full bar is wasted for vacuum... Which obviously is useless on a diesel.

However, since the MAP is mostly used for low-boost fuel control, by the time you hit 24 PSI you're already at full fuel and the boost level is pretty irrelevant. If you want to know exactly what your boost is, just put a gauge on it and leave it at that.

For reference, you can change the sensor to a full 3-bar, 4-bar, or 5-bar pressure only MAP or 5 volt pressure sensor, and then have the MAP sensor transfer function rescaled for the new sensor so that the OBD will display a correct value. We've done this in the past for special applications where we wanted accurate control of the low-boost fueling (anaeroid) as well as control of fuel up to about 60 PSI. This does require a large number of changes in the calibration and honestly isn't necessary in most applications.

I hope this helps.