When you first start your car and the Power FC is on what is your base reading? I keep showing a negative 4.5 (-4.5 kg/cm2). I wanted to know if this is normal or should it be higher/lower?

I can't really tell yet how to read this effectively. Anything would be greatly appreciated.

 

The PFC has slightly inaccurate Scale/Offset for the map sensor which causes vacuum and boost to read low. Boost is more off than vacuum.

With only the key turned on, you would expect 0 psi at sea level but most read some vacuum. When idling, it will read a higher vacuum.

And it is not kg/ccm2, vacuum is -N mm HG. That is what my commander shows.

Right now it is raining in Houston which means a low pressure area.
My calibrated map sensor is reading -3 mm Hg which is -0.05801032 psi.

 

I don't think I have the vacuum setting displayed. I only have the knock, water temp, air temp and the kg/cm2 showing on the screen. If you display the kg/cm2 will your readout be different?

 

post a pic

 

I wonder if you have a really old version. The newer ones read boost in mmHG, however if you look at the Apexi PFC instructions page 11 (14 pdf), it shows the boost in kg/cm2

http://www.banzai-racing.com/store_i...werFC_FD3S.pdf

Regardless of the units, it is normal for the boost to read slightly negative when the car is not running, with the key on. The closer you are to sea level the closer it is the 0.

For reference 1 kg/cm2 = 14.2 psi

 

Makes me wonder, does the new OLED commander switch from mmHg to kg/cm2 from vacuum to boost?

 

Just tested a non-OLED, it switches from mmHG in vacuum to kg/cm2 in boost, so my previous statement was incorrect.

You do not need to have an old version, these are the units of measure that the PFC uses.

However it is strange that you are getting a - kg/cm2 reading, it should automatically switch to mmHG in vacuum.

 

Thanks for the information everyone. This unit came with the car. I'm still trying to understand how to effectively use this unit. I will try to post a picture this weekend when I can get to the car. Honestly I don't feel confident to touch this piece of equipment as I do not want to screw up the settings.

 

I have a question regarding this as well. I just purchased my PowerFC and it is running great. However, I have noticed that with the key in the ON position and the engine not running, the Commander is displaying -150 mmHG, and at idle I pull around -485 to -450 mmHG. My display does switch between kg/cm2 and mmHG in boost and vacuum, respectively (I just purchased this PFC brand new from Banzai last weekend).

I'm at 4989ft of elevation, so I understand I have less air pressure in my environment. When I used the datalogit to try and calibrate the MAP sensor so it read as close to 0 with the engine off as possible (I got it to -0.3mmHG) it doesn't like running with that MAP calibration at all. However, it seems to run very very well with the current MAP calibration.

For further reference, I hit a max boost pressure of roughly 10psi (maybe a few tenths of a PSI higher) according to my AEM Analog boost gauge, and the Commander shows a max boost value of 0.49kg/cm2 so it's about 3psi off. Is this normal?

 

Return it to the factory preset setting for the stock sensor.

Again the calibration is based of sea level, you are 5000 feet. By forcing it to read 0, the calibration is off.

.49kg/cm2 = 6.9psi, you do not want your timing that far off, when you are really hitting 10psi (.70kg/cm2)

 

What is the factory preset setting for the stock sensor? Do you have the scale and offset? I currently have the base map that ships with the PFC in the car and the scale is back to the base map setting for PIM option 1. This is where I'm reading -150mmHG.

 

If you have the stock map sensor in the car it should be set on normal 5263/3947.

Do not let the negative reading bother you, I am at 1000 ft and the typical reading is -50mmHG not running.

However you will need to tune your car for your elevation.