I want to install a brake pressure sensor in my 348

Hey everyone. I'm looking to install a brake pressure sensor in my 1992 348tb so that I can data log it. The trick is finding out how to plumb it into the system with minimal permanent modification. I have previously worked as an automotive engineer, but my expertise was in powertrains and my knowledge of brake systems is mostly theoretical, with only a moderate understanding of the practical side. I am hoping that somebody here can offer their expertise from experience. So far I pulled my upper trunk carpet to take a good look at the master cylinder/pressure accumulator. I have noticed since purchasing the car back in March that a lot of the systems have been designed with thought given to racing and future modification. With this in mind, I was sort of hoping to find a blanked off plug somewhere that would make plumbing a pressure sensor simple. It appears that no such thing exists. In addition, after perusing the workshop manual, it appears that no part of the master cylinder itself has what could be called "unaltered pedal pressure" (in the sense that all of the fluid in the master is servo-assist pressurized in some way during operation). In my mind I was hoping to log that "raw" pressure from the pedal action, but perhaps that isn't how it is normally done. Obviously I could use some sort of force gauge at the pedal connection but I have never heard of this being done. To summarize, here are my questions:

1. Has anyone here already installed a brake pressure sensor in their car?
2. Is brake pressure normally data logged pre- or post- servo boost?
3. If it is logged post- boost, which brakes' pressure is preferred for logging? (seems that front wheels would be more useful)

I realize that the simplest pressure sensor option would be to plumb a "T" fitting inline with one of the brake lines, but this solution seems inelegant compared to a solution at the master cylinder itself, and I'm still holding out hope of somehow logging the "pedal input pressure" as opposed to the delivered pressure to one of the wheels.

 

I think I might have settled on a solution. The red region in the picture is valved-in pressurized brake fluid from the booster. Based on the technical manual, this pressure is directly proportional to the amount that the brake pedal presses in. This red pressure acts on the piston that pumps the front brakes and directly acts on the rear brakes. It also acts to push the pedal backwards against the driver's foot. That would effectively make it the "raw" pedal pressure I am hoping to find. I probably should have read the tech manual more thoroughly before making this thread, because I noticed this about 20 minutes after posting last night. Anyway, this means that the entire rear brake line contains the pressure I need, so I need to tap into that somewhere. After a search of some open wheel racing and spec E30 forums, it does seem that people actually do plumb a "T" fitting into the line off the master cylinder, or sometimes use an extended banjo bolt fitting. I was hoping for a cleaner looking solution, but I can't see any other way of doing this. If anybody has thoughts chime in. I'll probably throw a pic on here once I install something.
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