foxbat

I wonder, are there any precautions in exceeding 30psi boost while using a JDM 3bar map sensor (SD tune). I previously tuned the car on 93oct fuel, setting boost at 29psi which is about the limit of the 3bar map sensor. Now I need to tune it with a water/meth kit installed & I'd like to increase boost to around 32-33psi. I know that the map sensor won't read boost beyond 29.something but I wonder if that would pose a problem tuning the fuel table in that bit of extra load especially that it's an SD, map based rom?

Tuxevo

iTrader: (8)

You'll want to get a new map sensor. The ecu is delivering fuel and adjusting timing based of the signal imputs that are coming from your map sensor. If it's taking a sampling that's outside of its range of opperation it's unlikely that the ecu will be behaving as you wish it to.
Example, turbo producing 32psi but map sensor says it's 29.06psi (max measurable pressure). Both timing map and fuel map reference the wrong cells and you end up with more advance and less fuel anytime you're outside the sensors range.

foxbat

Well what you said does make sense & is definitely applicable to the VE table, but fuel & timing tables are load based, will the ECU see load beyond the range of a map sensor in an SD rom? I'm not sure how the ECU emulates load readings in an SD rom. I think with MAF, you could max out the MAF & still be able to tune fuel based on load readings...correct? I wonder if the same can be done with MAP? It's just something that I never did before.

LetsGetThisDone

iTrader: (1)

No. In a MAF setup, the ECU calculates load based on the airflow readings of the MAF. In a speed density setup, load is calculated off manifold pressure, and you tune the VE tables to tell the ECU how much air is flowing at a given pressure. If you run boost past what the MAP reads, the ECU is flying blind. So, say your SD tuning/programming means the max reading of the MAP at 29.5psi is 300 load. Your ecu will never touch the timing/fuel tables past 300 load. So, whether the car hits 31psi, or 72psi, or anything above 29.5psi, the ECU still thinks its at 29.5psi at 300 load, you're going to get the timing and fueling values in those cells in the timing and fuel tables. Very unsafe.

foxbat

Very well explained letsgetthisdone, I guess I'll stick to max of 30psi, I'll try to achieve some gains by increasing timing a few degrees as I tune it with water/meth.

TrendSetter

iTrader: (1)

its doable, the ecm will use the values at the end of your tables. so if those values are appropriate then you are ok. a few psi you can likely get away with if you make those last cells a little rich. but i wouldn't push it too far past that.
i went to a 5 bar when i maxed out my 3 bar.

mines5

Can we some how get a warning in stock ecu that MAP limit is reached just like stand alone ECUs ?

mines5

JDM 3 bar map is the same that comes with JDM evo 9 and Evo x ?
I am want to use this to convert to SD with no IAT sensor. Is it workable ??
Also, i have 3 scalings - PSia 16 JDM3BAR , PSia 8 JDM3BAR ,, MAP kpa JDM 3 BAR .
Which one to use ?