Question on Fuel Pump Testing

Hi Nick.
Thank you for the quality and the clarity of your tech articls, they come really handy especially when there is a serious lack of information concerning BMW cars in general.
I'm trying to reproduce the test for my mini cooper s R56 but ther's something that I find really odd:
I've tested the pressur at the pump, it was higher than 6 bars.
when i test at the entrance of the HPFP, i get 3,2 bar and it only drops to 3 bars after 15 min.
I found a valve on the fuel filter housing and there is marked 3.6, i assume that it's the release pressure.
after cheking the part reference, i found that the fuel filter housing is commun between the cooper and cooper snormally aspirated and turbo.
So my question is, how are you supposed to read 5 bar in the circuit if you have a release valve that is set to 3,6 bars?
Thank you in advance for your help

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This post was auto-generated based upon a question asked on our tech article page here: MINI Cooper R56 Fuel Pump Testing (2007-2011) | Pelican Parts DIY Maintenance Article

[Casey at Pelican Parts]

That is a great question!! I do not know, but have verified that spec in multiple sources. What I think is going on is, that regulator supplies 3.5 bar OUT of the pump, and between the the LPFP and HPFP, the pressure is allowed to build up to 5 bar. Again I am not sure but that's the most logical guess I have for you!

- Casey