zooq

which one should i believe?
my boost guage reads 22 psi and the PFC only reads 1.15 kg ( 16.33 psi)
i still have the stock map sensor, and i'm running the stock twins NS.
i know that my guage is off by about 1-2 psi at lower boost, but a 6 psi difference at high boost WTF?

IGY

You do realise that the stock map sensor stops reading around 1.15 and the boost could be over and it will still display 1.15 on the pfc. You should count yourself lucky that you haven't shelled the motor yet. Turn the boost down until it only reads 1.00 on the pfc and see if the other guage reads 14-15 or something different.

jeff48

IGY is right about the maxxed out display with a 2 bar sensor. The PFC is not always as accurate as the boost gauge, but depending on the brand of gauge, it may be more or less accurate. The only way to figure out which to rely on as a baseline, is to test both the PFC and gauge with a mityvac.

Tim Benton

iTrader: (1)

I think Chuck has shown that the PFC is "reading" the boost value correctly, but the displayed boost on the commander is incorrect. Correct me if if that's changed Chuck.

Tim

cewrx7r1

iTrader: (2)

The stock map sensor output voltage is not linear as boost increases and reaches a max of about 4.9 volts.

The PFCs calculation of PIM ABS and displayed boost is also progressively off as boost goes up.

Go see the thread about not reading 0 boost with the ingnition on but engine not running.

zooq

IGY, i only saw 12:1 AFR at redline. and the air temp were in the 30s C . i have 2 850s and 2 1300s . so could it be a true 22 psi ?
Is it too hard to hook up a 3 bar map sensor. i already bought an FC logit.

zooq

i noticed last night that it still reads 17 psi when i run .9 on the PFC

jeff48

test with the mityvac----something is wrong somewhere. BTW--- AFRs of 12 at WOT are NOT safe.

Tim Benton

iTrader: (1)

good call Jeff....need to be 11.5 or richer.

Tim