stock BNR32 GTR hitting max load?

[mike2016]

I did a few baseline run on my almost stock BNR32, wanted to make sure the car is behaving normally without issues, and have something compare to before I start changing / adding stuff.

The only thing that has been done to the car, besides suspension are

1. removed boost restrictor ring (still running stock boost solenoid, nothing else touched)
2. Nismo exhaust with dual high flow cats
3. Nistune ECU of course.

Running stock map

I did several 3rd and 4th gear pulls and logged them, when playing back I noticed it's hitting TP load max at the end.

Is it caused by the slight increase of boost? it's only increased from 7 psi to 10psi.

Almost all of the values on TP Load Max table are 88 from the middle to the end. How do you calculate the % to drop the K?

[madaxgt]

You should post a log, easier to diagnose problems. Whats the voltage on your maf sensors, although going from 7 -10 psi i would not expect them to max out unless you have a boost leak... 7psi is too low for a stock rb26 with restrictor. They should be roughly 0.7bar with restrictor so 10.29psi.

[Matt]

Yes log file would be great. Even if you are hitting the end of the fuel map, what about the timing map? What TP max are you seeing (log would show this)

The fuel map scales are normally shorter than ignition scales and it will just use the last column values, which should be okay

[mike2016]

How do you post a log here?

I just checked the parameters on one of the pulls where it hit the max load

RPM - 5775
Speed - 117km/h
AFR - 11.09
Throttle - 3.88 V
Injection time - 14.78ms
Load Index - 88
TP - 22528
MAF LHS - 4.590 V

You are right about the boost pressure, I'm only looking at the stock boost gauge, and it's maxed out the factory reading 0.7 bar.
I'm still looking for a 5v boost sensor that will work with the LM-2 so I can log the boost pressure, haven't had luck so far.
Don't want to add any extra gauges or change the appearance of the factory look.


Matt,

I'm hitting the last 2 columns of the timing map, when max load is hit, it's at the last column of the timing map, as well as the fuel map.
When load is near max (2-3 columns from the last), it hits the same columns in fuel and timing.

TP Max hits 88(last column) quite often


Why are the last few columns of TP Max Load are all 88?

[Matt]

This is the sensor you want. Now made by NXP (used to be Motorola/Freescale)

MPX4250GP NXP SEMICONDUCTORS $14.67AUD
EAR99 Pressure Sensor 0.2V to 4.9V 0kPa to 250kPa Gage A

I got mine from Arrow electronics Australia, but should be available elsewhere (Digikey, Mouser, Element18 etc)

[Matt]

ECU is limiting the fueling from load calculation from 3200rpm above load 88 it would seem, to then make it only add more fuel solely from the fuel map rather from any extra boost (if any)

Which is interesting, since load capping at 88 also matches the load max in the fuel map at same value

[mike2016]

Matt,

My apologies, i actually meant a boost sensor that takes 12V in and outputs 5V for the LM-2.
I guess no such sensor exist, maybe I'll just get the SSI-4 and hook up a sensor.

Is this a normal behavior for stock R32 with just exhaust and removed boost restrictor?

I'll post a log file here, should I use dropbox ?

[Matt]

You can post the log here. It seems that's the way Nissan intended it from the ECU side of things. We use the standard maps from their ECUs in our boards

With the boost sensor, you will not get one with 12V power. You can either use the 5V power and ground from the ECU (goes to the TPS switch) and route that to your sensor, or run a 12V to 5V regulator from vehicle power to give it the voltage it needs

[mike2016]

Here's a log file.

you can see at almost every full throttle run it maxes out the TP load

The AFR looks good, so I guess fueling is ok? It's running a bit rich but it's consistent.