My Defi boost gauge shows I'm running 16psi, avcr says 1.05kg, which is around 14.8psi I think, and the PFC says .96, which should be right around 13.6. This is a pretty big difference and since they all are rather expensive peices of equipment I would have thought they would be pretty close. The PFC also reads about 50mm more vacuum at idle than the avcr. But the avcr reads .02kg with the car not running. Which one would you guys trust?

Thanks,

Nick

 

The PFC converts the output voltage of the map sensor
to pressure. Unless you test your MS against pressure, there is no way to verify the PFC as correct.

I once compared my Autometer to HKS boost gauges from 0 to 14 psi by hand pump and they matched exactly. Then I did the same for the MS and used Mazdas specs for it. It was about centerd in the given voltage ranges. Then I looked at what the PFC read. Mine read low. 14.2 psi by meter and 13.0 by pfc.

Do not trust the PFC.

 

These discrepancies drive me crazy. I use the PFC for boost control, and I've got it set at 0.9 kg/cm^2 which is ~ 12.8 psi. At WOT my peak boost per the PFC is usually about 0.91, however my Apexi EL boost gauge shows 1.10. Am I really pushing 15.6 psi through my turbos!?!?