Why does my manifold pressure read higher than my pre-throttle boost pressure?

Body:Hi everyone,I have a question about a pressure reading issue on my turbo car.

My setup is:

Boost pressure sensor is installed before the throttle body (pre-throttle)

MAP sensor is in the intake manifold

Sometimes the manifold pressure (MAP) shows a higher value than the boost pressure sensor

This happens mainly during partial throttle or transient conditions

Under WOT, both values get closer, but MAP still sometimes spikes higher

I would like to understand whether this behavior is normal, or if it indicates a sensor/scale/configuration issue.

My thoughts so far:

Pressure drop across the throttle plate during partial throttle

MAP reacting faster to engine demand and pulsation

Exhaust backpressure (EMP) causing reverse pressure waves during valve overlap

Pre-throttle boost sensor responding slower due to hose length or placement

Possible calibration/scaling difference between the two sensors

Absolute vs gauge pressure mismatch?

Questions:

Is it normal for MAP (post-throttle) to spike higher than pre-throttle boost under certain conditions?

How do you normally diagnose this in MoTeC / Haltech / Hondata logs?

At WOT, should pre-throttle boost always be higher than MAP?

Could high exhaust backpressure (EMP) cause MAP to exceed pre-throttle boost momentarily?

What’s the typical pressure behavior you see in your logs?

If needed, I can upload some log screenshots (MAP, Boost, TPS, RPM, IGN, Lambda).

Any insight from people who have dealt with this would be greatly appreciated.Thanks!

It could well be pressure wave harmonics in intake system when air charge gets reflected from closed intake valves and goes back to intake plenum which has bigger inside diameter resulting in lower air velocity but higher pressure. It can be just one or the reasons among all others you named...

Is it the same story if you switch places between pressure sensors?

I'm making an assumption based on your screenshot that you're using a MoTeC M1 with a GP based firmware.

The behavour you're seeing is caused by Inlet Manifold Correction. Check the help on this it's pretty extensive.