MAP sensor upgrade Power FC
 

Chasing some info on MAP sensors. I seem to have an issue with what feels like boost cut above 1.1 kgcm2 on the FC Commander.

I first started having these issues at the plex doing the Rally Sprint. First I thought the car was over-boosting (which technically it was), then I thought there was a ignition problem (which I still believe to be true). I have changed over to the later model black coil over plug and completed the necessary wiring changes. The car runs fine now up to 1.1 is bar, then pop pop bang.... goes the exhaust & loss of power if I go over this set point.

My fuelling is all good & I do have room in the injectors up top (running at 88% now at 1.05 kgcm2 @ 10.8 - 11.2 AFR & 22 knock at full noise) I think everything else is good in the tune, albeit still a little rich, but that's OK by me.

So I have started to do some reading & have come to the conclusion that the early model WRX's MAP sensor can only read up to approximately 1.2 bar. I have read that the later 98-99 models can go up to 1.5 ish bar, is this correct?

Could anyone confirm if this is correct & if so the part number for the later model MAP sensor & or solenoid. Also is this just a direct plug & play & run a bit more boost, or does the boost settings need to be re scaled due to the higher reading MAP?

Sorry if this is not worded quite right, but I'm just learning :o

Havnt you got a Z32 afm?

Yeah I do

the power fc only likes boost up to 1.8 bar from memory.

stock gc8 my99 sensor will read up to around 1.64 bar, so you should have room afaik

in any case, i dont think power fc does MAP fuel calculation, only for boost cut.

unless you have one of those djettro variants..? ross would know :)

Correct Stace.

Its not the pro version & I dont believe the D-Jetro version comes out for WRX

Boost control is set toi allow up to 1.4 bar. I can only go to 1.1 ish before it feels like boost cut.

So I have read [URL="http://bbs.scoobynet.com/general-technical-10/840204-polar-performance-chip.html"]HERE[/URL] the earlier models only go up to 1.2 bar, which could explain why I am hitting this boost cut. I am hoping the MAP sensor is being maxed out & then cutting the fuel as it would if it reached its setpoint (when set to under 1.15 - 1.2 bar) as a boost cut.

The 99 model MAP sensors can read about 0.4 bar higher "apparently"

Is this making any sense, or am I heading a totally wrong direction? & something else is to blame?

crimp the line to the boost sensor, give it another squirt around the block.

its not used for calculation, so as long as there is 'pressure' - ie atmosphere, then it will work.

did the trick for me years ago.

Ok Stace I will give it a go, but when I get home I ma at work at the moment. But, just to clarify.

PFC takes its boost reading from here I think - I do keep an eye on the boost pressure from the commander. No big deal though, I can see the boost pressure on the gauge

The MAP sensor on my car is for boost cut only?

thats the only reason they have them on earlier cars with air flow meters

later model cars use them in more of a closed loop fashion.

10 - 4 Rubber Duckie. Cheers Stace :)