Quote: Originally Posted by
CapnBoost 
Which cars don't measure boost? Most cars have a map sensor even if it's not highly weighted by the ecu. It's easy to add one if there isn't. Thermocouples are a little more difficult but any tuner worth paying should know how to do those.
Just about every auto sensor reports in 0-5v, there are daughter boxes on the market now that will collect and log this data. I'm not sure how to build something similar to xmit via usb or similar interface. If all you want to do is display it should be as simple as a wafer board and lcd display.
How can you say 'most cars have a map sensor'?!?
Mine Nissan's SR20DET hasn't! There are two systems commonly in use today - MAP, and MAF.
My old Rover T16 engine had a MAP sensor, but no MAF sensor, its usually one or the other, not both!
An airflow system has no need to know boost pressure, Boyles law tells us that pressure, volume, and temperature are all constrained to one another so off volume and temperature, pressure can be calculated.
MAF systems are generally more accurate and hence why most modern cars use MAF setups and not MAP systems.
I advise you to go do some reading
