CloudPump

iTrader: (2)

Hi Guys,

1992 JDM RHD FD, lots of mods but I'm not sure it's worth listing them all out as this question pertains only to the PFC & AVCR.

I have my AVCR set to limit my boost to .8 kg/cm2 and it holds this perfectly, no issues here.

However when I check the peak boost on the AVCR it reads 0.8 kg/cm2

When I check peak boost on the PFC commander it reads 0.72 kg/cm2

I have a manual boost gauge that reads about 10-11psi (I can't be exactly sure if it's 10 or a little over 10 due to angles and the fact that I need to be looking where I'm going)

At any given time they're always off by a little bit from each other. I've changed both the MAP sensor on the car and the Pressure sensor on the AVCR with brand new ones. The readings are always off the exact same amount.

Has anyone else experienced anything like this?

Which should I trust? I know the car is being fed fuel based off of what the PFC reads, but how can I be certain that the PFC is getting the correct boost information?

Thanks,

-Geoff

cewrx7r1

iTrader: (2)

It has been known since 1999 that the PFC PIM Scale and Offset is wrong which causes the PFC boost values to show/log low.

GoRacer

iTrader: (2)

Yikes, I thought it just read in different values and needed a conversion. Anyway, the kit comes with a 3-bar map sensor. I'm not sure if it makes any difference under 1 bar though. Doesn't the AVCR use the exact same boost controller as the PFC kit?

arghx

iTrader: (3)

The AVCR uses the same solenoid, yes. It's just a Denso 3 port solenoid--nothing special about it.

On-board Pressure sensors are never going to 100% agree. Part of it has to do with mechanical tolerances and the other part has to do with the scaling of the sensor voltage, as Chuck mentioned.

cewrx7r1

iTrader: (2)

I had posted years ago about how to calibrate your map sensor and use some "XYZ" software to calculate the correct scale/offset. This works for all map sensors.

Search for it or contact arghx to join the private PFC group and get all the notes and software.

arghx

iTrader: (3)

Yes, you can change your MAP sensor scaling. You don't have the option to change the sensor scaling on the AVCR though.

CloudPump

iTrader: (2)

Just to clarify. I don't have the PFC boost control kit, I control boost through the AVCR. The two values I'm referring to are the PFC's handhold commander which gets it's reading from the factory MAP sensor. The AVCR comes with its own pressure sensor and I'm reading the AVCR display.

My main concern is that while I'm currently running safe boost levels, I have a fuel system waiting to go in along with water/meth and I'll be looking to turn up the boost.

I find that the higher the boost goes the wider the gap between the two readings.

I suppose all that's really important is that while tuning I make sure my wideband doesn't let me go lean.

-Geoff

thewird

iTrader: (8)

Gauges will never match, you have to work with what your given. The stock FD map sensor with its calibration will always read low. They all do it, not just yours.

thewird

CloudPump

iTrader: (2)

The part I've bolded makes me feel better.

So when the factory sensor says 10psi it's actually higher...

-Geoff

thewird

iTrader: (8)

Correct.

thewird