It goes from 0 to 45 mmHg, but what is that in PSI?

 

like 9 or something

 

iirc it is 45mm X 10 which is 450mm in which case converts to 17psi, the gauges seem fairly innacurate and i don't see why they would need to read that high since fuel cut is 9.6psi on the s5 and 8.5 on S4.



i hate math but here is the formula:

psi = mm of Hg x (1.9339 x 10-2)

that is 10 to the second power.

 

nerds...

but seriously, that should have been 10^2

 

450mmHg is equal to 8.7psi

 

heres a pressure conversion calculator

http://www.teamfc3s.org/calc/convert_pressure.php

 

does the stock gauge physically read pressure or does it "guess" like DSM boost gauges?

 

I believe it takes a signal from the ECU which reads from the boost sensor

 

Ahh the dreadded DSM gauge I hate my starion for that. 5psi at idle my *** it only boosts to 7psi.

And here I thought it was psi = mm of Hg x (1.96439 x 10^2) oh well wont be the last time I am wrong.

 

No. It reads it from the boost sensors output wire, the brown/red wire. The same one that splices off and goes to the ECU. The ECU has nothing to do with how the boost gauge reads.

Depin the pin 2B on the ECU and the boost gauge will still read as before (series four pin 2B).

 

Eh, well I was halfway right.