Hi

Today I noticed something which is as follows. At WOT i noticed that my pre and post throttle MAP sensors read differently,
at higher pressures, to be precise the post throttle MAP reads 150-200kPa less than the pre-throttle one.
Both sensors are calibrated correctly and are verified with a hand-pump. As far as I know a pressure difference is normal,
but since i am not a pro I wonder what difference is mostly normal and I wonder if too much or too less of a difference
indicates something, like a too small throttle valve being a restriction would cause higher readings due to pressure building up or something. Of course this might have an influence on fuel pressure as well because the FPR uses a post-throttle reference line.
Sorry if this is a stupid question, I am just cuorious

Thanks

I am running the 03K 906 051 4bar map with DSLGRAD=437.5, DSLOFS=31.25.

I can only be as certain as the ECU tells me which is wdkba=100.
It's a 2.7T, the pre-throttle map is what i said in the previous comment and the other one is a VEMS 4bar MAP sensor,
which is hooked up to a VEMS ecu in the glove compartment which i use to log dual egt, dual lambda (also feeded to ME7)
, oil and fuel pressure, and the MAP of course, this allows me to use my cellphone to display all the variables I want, but anyway, the VEMS MAP value is a MAP value so it is absolute, and their unit is kPa, but that does not really matter at this point.

Well.. if you trust the VEMS MAP you can use it to calibrate the pre tb map

Or maybe 5% drop even at 100% throttle plate is expected.. Does the % vary with airflow?

It's an RS4 throttle body and RS4 intake manifold. But anyway I will keep testing.