Summary of Software

ProECU software has been introduced to allow reprogramming of the factory ECU in order to tune the necessary components of the calibration in order to allow for modifications and increases in power.  This is not a standalone repalcement ECU so you shouldn't run into the associated issues or disadvantages of setting up a purpose-built ECU and control system from scratch.

The software allows easy control over most factory parameters including:

• Boost Targets and wastegate control

• Target AFR

• Ignition Timing

• Fuel Delivery including fuel pump calibration (using the same style pump as OEM)

• Airflow Measurement and fuel compensation

Programming

For information on how to program as well as flash recovery, check out.

• ECU Programming Overview

• How to Recover an ECU
  
  

For more software guides check out:

• Software Help and How-To

To Look Out For

It's a good idea to keep an eye on your clutch pressure actual vs target while tuning.  A difference between the two will likely mean the clutch is slipping at that time.

Supplemental Content

Platform Specific

General

• ECU Programming Overview

• Software Help and How-To

• EcuTek Knowledge Base

Tuning Guide

Accelerator

The Normal, Slow, Fast, Safe and Trustful Accel Maps define the ratio between the Accel Pedal % and throttle butterfly opening angle.  The 3D map called Accel Slow/Fast Switch defines the vehicle speeds between the Accel Map, Normal Slow and Accel Map Normal Fast 2D maps. The below screenshot shows that the  Accel Map Normal Slow map is used at lower vehicle speed (below 30kph) 

Accel Map Normal Fast map is used at higher vehicle speeds (over 80kph), and 80% of the Accel Map Normal Fast map is used at 60 km/h (the other 20% is interpolated from the Accel Map Normal Slow map). 

Alternate maps are used whilst in Safe Mode from the regular Normal Mode maps.

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Throttle Body Tuning

The Primary maps used to re-scale the throttle airflow requirements in Nissan vehicles are the Throttle Position Sensor (TPS) scale maps.

These maps relate throttle opening area to angle, and (in GTR) the scale goes from 0-27.585cm^2 column at angles from 0-87.23, by increasing the throttle area for the same angle, the ECU will know to open the throttle less for a given target airflow (throttle open area and pressure related).

Tuning a Bigger Throttle

Before you make any changes to the calibration its important to know the difference between the OEM and aftermarket throttles. The primary difference will be in diameter, the OEM throttle bodies are 60mm diameter and most of the aftermarket units are 68-73mm. What we need to know id the percentage change in open area between the OEM and After market throttles. this is done by calculating the difference in area (or diameter squared).

Percentage Difference in Area = (New Throttle Body Diameter)^2 / (Old Throttle Diameter)^2

e.g. 68^2 (Greddy)/ 60^2(stock) =  1.28

The first tuning step is to go to the TPS Scale Map and adjust the throttle open area by the increased percentage area difference, However, due to the 60cm^2 limit we cannot increase all of the values in the map we must go up to nearly below full open angle and blend appropriately. In the example we would modify as follows, First scale up the map by the desired amount

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then Blend the map so that it does not give a rapid drop but the last value is still the same as OEM

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Once the maps has been scaled correctly you must copy the map and paste it to the TPS Scale Trustful map to ensure they are identical.

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Idle Airflow Maps

Depending what other modifications have been made to the car the idle airflow targets may need to be adjusted. If the vehicle is stalling idling erratically or not recovering from overrun conditions you may need to use the idle airflow target maps (for drive and neutral and 2 different modes).

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It would be good practice to make the airflow target match the actual airflow consumed when idling in both Neutral ad drive, simply log the mass airflow in both situations and set the maps to be the same amount. There are unit converters available for converting from l/min to g/sec but at at 300l/min it converts to roughly 5.8g/sec.  

You may also want to increase the idle airflow target to try stop the RPM dip on overrun.

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It may also require raising throttle angle limits but generally when increase throttle size you will require less angle for the same airflow so they shouldn't need lifting.

Special Note

While you can change the throttle plate diameter the throttle position sensor characteristics cannot be changed, the A/D conversion performed inside the ECU has not been dissembled to a level to allow this. It must be the same as the throttle position voltages below otherwise DTC's will occur.

 

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Boost Control

Factory Boost Control – Not Recommended

The factory boost control on the GTR is very clever even though it can appear complex at first glance.

EcuTek have spent many many hours on hard disassembly to understand the factory boost control strategy. Spend some time to look through the various boost control maps to understand the various limiters and airflow control logic. Below is a description of each of the important boost control maps.

Boost Target

Shows the target boost pressure to try and achieve for an Accel Pedal position and Engine Speed.

Boost Target Max Allowed

This allows you to reduce the target boost pressure depending on the coolant temperature.

Desired Turbine Wheel Airflow 

This map must be calibrated to the characteristics of the turbo. Once set, desired boost can be adjusted via the Desired Boost map. This map will need to be modified if larger turbos are fitted. It will also need to be modified if the flow of the exhaust, intakes or intercooler are improved.

Turbo Dynamics - Integral Step

This shows the Integral component value added to output of the Surplus Airflow value in proportion to the size of the current boost error. Note the factory map does very little to correct a boost error at lower airflow! (It only corrects midrange boost error). Only at higher airflow will the factory Integral values make a reasonable adjustment to wastegate duty correction.

Raising these values too high will make the boost unstable.

This Integral value is continuously added for any boost error.

Turbo Dynamics - Proportional 

This shows the Proportional component value added to output of the Surplus Airflow value in proportion to the size of the current boost error. Note the factory map does very little to correct a boost error at lower airflow! (It only corrects midrange boost error). Only at higher airflow will the factory Proportional values make a reasonable adjustment to wastegate duty correction. Raising these values too high will make the boost unstable. The Proportional value is a fixed value correction that is added to the Surplus Airflow and this will not increment like the Integral value.

Turbo Dynamics – Sum

This Live Data parameter shows the Integral and proportional components combined addition. Consistently high positive values suggest the Desired Turbine Wheel Airflow (DTWA) values should be reduced (overboost condition), negative values suggest Target Boost is not reached and DTWA values should be increased to reach the Target Boost.

Surplus Airflow to Wastegate Flow

The surplus Mass Airflow is multiplied by a value from this map in order to calculate the flow rate of exhaust gas that must be vented through the wastegate. This map may need to be modified if larger turbos are fitted, as the relationship between exhaust gas flow and pre turbo exhaust gas pressure will vary.

Wastegate Flow to Opening Angle

Once the required wastegate airflow is known, this map calculates the wastegate opening angle required to vent the desired flow. This map is calibrated to reflect the characteristics of the wastegate orifice. You only need to modify this map if you port the wastegate orifice.

Wastegate Angle to Duty Cycle 

This map is the final wastegate duty that will be used by the ECU depending on the current boost pressure and the desired wastegate valve angle. These values can be reduced by 50%+ on vehicles fitted with stronger actuators (1bar+) and/or larger turbos.

Converts desired wastegate opening angle to the wastegate duty required. Values vary with the current boost pressure, since the pressure feed to the actuator diaphragm is fed from the boost pressure. So for a higher boost pressure, a higher wastegate duty (bleed off) is required to maintain the correct opening angle. You only need to modify this map if you replace the wastegate actuator or alter the spring tension.

If correctly understood and calibrated the boost control will be extremely competent.

In our experience using the RaceROM Boost Controller we can accurately recalibrate the boost control for different pressures with precision calculations and detailed log files to cross reference.

In the majority of cases the only map that should be altered is the Desired Turbine Wheel Air Flow map. Following the steps below will enable you to make accurate boost control calibration.

• Make a log at 0.8 bar, 1 bar and 1.2 bar (assuming you are able to run these different pressures without risk of damage to the engine) be sure to include all the important parameters used in boost control as listed in Live Data section (like Calculated Airflow, Wastegate Angle and Turbo Dynamics)

• Compare Target Boost and Boost Error and Calculated Airflow. By opening the Desired Turbine Wheel Air Flow map you can now see the corresponding Target Boost and Calc Airflow lookup parameter and this can be verified as the diagnostic parameter called Desired Turbine Wheel Output.

• If the boost is under target then the Desired Turbine Wheel Air Flow values needed to maintain the turbine speed are too low (and hence the boost is low), so simply raise the values to increase the amount of airflow that will hit the turbine wheel and increase turbo speed!

• The same procedure can be applied for an over boost situation.

• For greater accuracy set both Turbo Dynamics Integral and Proportional to Zero during boost calibration.

A final boost tuning tip is if your Target Boost is 0.8 bar and you generate a steady 1 bar then simply copy and paste the Desired Turbine Wheel Air Flow column for 0.8bar into the 1 bar column! This can be repeated for other boost targets as well.

We also advise that you start your tuning based on any EcuTek example ROMs where available. The example ROMs have the Desired Turbine Wheel Air Flow maps calibrated and in addition the X axis rescaled for greater resolution at higher RPM.

Boost Limit (RaceROM) and Boost Limit Resume (RaceROM)

The ECU will cut the Fuel Injectors if the Boost pressure (in Bar Absolute) exceeds the value in the Boost Limit map for a given atmospheric pressure. The Fuel Injectors will restore at the corresponding pressure shown in the Boost Limit Resume map.

The factory maps called Desired Boost and Desired Boost compensation are no longer used.

Camshaft Timing

Intake VVT

These four maps (MODE1 to MODE4) control the angle of the intake cam (note that 1 degree at the camshaft is 2 degrees at the crankshaft). This number is in camshaft degrees before Top Dead Centre. 

The RaceROM Map Switching feature allows you to define multiple different calibrations in the ECU ROM. A separate Inlet VVT map is provided for each mode.

Modifying the cam timing map can increase power and turbo response, but too much advance can significantly increase in cylinder pressures. This is dependent on Camshafts, Turbocharger and naturally any item which will change. Increasing to 28-32 deg will significantly improve turbo spool at low rpm.

Fuelling

The Nissan GTR fuel control is fully closed loop from Idle all the way to the rev limiter including light load and full load.

The logging parameter called AFR TARGET will show the current AFR the ECU is trying to achieve. EcuTek have converted the factory Nissan AF sensor voltage into a more useful logging parameter called AFR Sensor Bank 1 and AFR Sensor Bank 2.

Typically on a stage 1 car the AFR Sensor Bank 1 or 2 might show 12:1 AFR but independent Wideband sensors (like Motec PLM) will show a more truthful and accurate 11.5:1 AFR. We suggest you always verify your AFR with an aftermarket wideband sensor until you have enough experience to trust the standard sensor readings. The AFR shown will tend to be slightly leaner than the car runs but this can change with full decat exhaust and larger turbo’s (and higher EGT).

Fuel Trims

Increasing fuel pressure from say 3.0Bar to 4.0Bar will not change the AFR as the Short Term and Long Term Fuel Trim will compensate to achieve the Target AFR shown in the fuel map, so watch the Fuel Trims carefully.

Fitting a larger Intake MAF tube (stock 66mm to 76mm is a popular swap) will cause the Fuel Trims to compensate for the under reading MAF so ensure you watch the Fuel trims and rescale the MAF accordingly.

The short term fuel trim can add or subtract up to 25% (75% to 125%), the long term fuel trim can add or subtract up to 10% (90% to 110%). You should aim to keep the FT within 10% (90% to 110%) for a good calibration (ignoring transient movements), good calibration would be within 5% and the gearbox control will also show its appreciation.

Here are two examples of Fuel Trims in action, the left log file shows really good fuel trims but the right log file is adding +17% to the Injection Volume to achieve the target AFR. If this FT was 117% across the whole RPM range then the 1d MAF scale byte should be increased but as this is only at higher RPM then I could be a secondary fuel pump issue failing to deliver at higher RPM.

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Fuel Injectors

The standard Injectors will be close to 100% open when running 1.1 bar boost at high rpm (6000rpm plus and 560bhp+) so watch carefully, a vehicle fitted with a full sport exhaust system running 1.2bar+ will max the injectors. 

EcuTek can supply the high quality Bosch Motorsport Injectors that are 1050cc (good for 1000+ bhp), see them in the webstore.

The maximum Injector size you can enter in the factory map is 800cc, this is a limitation of the Nissan ROM code and not EcuTek. 

For replacement Injectors over 800cc use the map called Injector Flow Scaling (RaceROM) you can choose a different Injector size for each of the map switch modes (useful for Ethanol tuning in different modes).

For more information on scaling fuel injectors using the OEM method check out our article Scaling Injectors For Nissan Using OEM Method (GT-R, 370z) or for information on RaceROM injector scaling visit GT-R RaceROM Injector Calibration

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If the Injectors are to be replaced then choose at least 800cc plus. When fitting larger Injectors it’s important to reduce the Minimum Open Time from 1.8ms down to 1.2ms, otherwise 1.8ms on 1000cc Injectors will mean 12:1 AFR at Idle. Using the EcuTek 1015cc Injectors we typically run a 1.0ms Offset combined with a 975cc Injector size and we achieve very tight fuel trims.

Fuel Map MODE1 to MODE4

The Nissan GTR fuel control is fully closed loop from Idle all the way to the rev limiter (including light load and full load). The fuel map contains an AFR TARGET based on Engine Speed (RPM) and Calculated Engine Load (%). 

The vehicle has two factory fitted wideband sensors (one for bank 1 and another for bank 2). The ECU uses Fuel Trim Short Term Bank 1 and Bank 2 to ensure the target AFR is achieved. Further to this the Fuel Trim Long Term Bank 1 & 2 will make long term adaption trim for continuous Short Term Fuel Trim corrections.

The RaceROM Map Switching feature allows you to define four different calibrations in the ECU ROM. A separate fuel map is provided for each mode.

The four separate fuel maps are 26x19 in size providing 200% more resolution than the factory 16x16 fuel map (that is no longer used).

Fuel Map Safe Mode

This AFR target fuel map is used during Safe Mode.

AFR Target – Max at WOT

This is the leanest AFR Target permitted for a given RPM when at WOT. Of the values returned by this map and the main 3d fuel map(s), the richest value will be used by the ECU. Raising the values in this map to prevents rich AFR Targets interfering with the intended target AFR typically used on high power cars with modified exhaust systems. Setting all the values in this map to 14.7 will completely disable the effect.

AFR Conversion Table B1/B2

These two maps (one for each bank) are used internally by the ECU to convert values in the main fuel map to bank specific AFR targets. The units are Equivalence Ratio and can be converted to AFR by dividing 14.7 by the values in the table, for example 1.00 gives an AFR of 14.7:1 and 1.336 gives an AFR of 11:1.

By default these tables do not give an output identical to the input, and it is different between each bank.  The maps typically translate values from the fuel maps at high load to slightly richer targets. To nullify this effect, set that the data values to exactly equal the input values, but be aware that the result is that the reported AFR target and AFR logging parameter will not match when long and short term fuel trims are 100 (no trimming).

Fuel Enrichment Safe Mode (Early Gen 1 models only)

This is the fuel enrichment factor added when the ECU is in Safe Mode to protect the engine. 

Fuel Trim Per Cylinder

This map can be used to add extra fuel to certain cylinders.

Injector Flow Scaling (RACEROM)

This map defines the injector size for each of the 4 different modes. 

You can select Injector scaling values for each of the for Map Switch modes. This is useful if alternate fuels are used. When using E85 you can simply reduce the Injector scaling size by 30% and the fuelling will deliver +30% more injection volume.

The top value is MODE 1 the bottom value is MODE 4

If the Injectors are to be replaced then it's recommended to choose at least 800cc plus size injectors.

EcuTek can supply the high quality Bosch Motorsport Injectors that are 1050cc (good for 1000+bhp).  They are tried and tested are not susceptible to some of the Idle and black smoke issues that some other brands do.

Injector Lag Time Multiplier and Offset 

This should be used to recalibrate for larger fuel injectors. This is sometimes called injector dead time or injector latency.

Different design fuel injectors will have a different response time to the original injectors so always check with the Injector manufacture if this information is available before purchasing. EcuTek offer the tried and tested 1050cc Bosch Motorsport Injectors that have better characteristics than the stock injectors! When using our injectors the multiplier is unchanged but the offset is increased to 1ms.

Injector Minimum Open Time

This value may need to be reduced when fitting larger injectors over 900cc, we suggest around 1ms.

Fuel Consumption Meter Calibration

This value should be increased if larger injectors are fitted to keep the fuel consumption display accurate on the instrument cluster. Set the value the same as your Injector size.

AF Learning Range RPM - Load

These are the breakpoints for the adaptive Fuel Trim Long Term stored correction values that are learnt over time. These can be adjusted to help calibrate Fuel Trim more accurately during tuning. 

Injection Angle

This shows the injector firing angle before TDC, increasing these values by around 40-60deg during spool and peak torque can help avoid black smoke, this can become more apparent where larger injectors and more increased cam advance has been used.

Fuel Pump Control

The Primary Fuel Pump is controlled by the ECU as a 3 stage Duty Cycle that switches as a certain Engine Load% is achieved, the Primary – Duty Cycle Low (34%), Medium (67%) and High (100%), these duty value amounts can be altered in the top 3 maps shown below. 

The Primary – Load Thresholds #1 – #3 can be used to alter the Engine Load at when the ECU switches between Low/Med/High. The factory setting have been configured so that during a full load pull the Duty steps from 34% to 100%, this can be altered using the threshold maps.  Read the each individual maps HELP text to understand which Primary Load Threshold controls which control range.

The Secondary Fuel Pump is a simple ON/OFF switch and what is very important is that the 2^nd fuel pump is switched ON against the Fuel Injector Open Time %.  This is very important to change this when using larger Injectors, see the Tuning Sections for more info on recalibrating the 2^nd Fuel Pump switch threshold.  

The logging parameter called Fuel Pump Status Main – Sub will show the current status of fuel pump control as shown below the status is:

• Fuel Pump Status 1 - Primary Pump High Duty

• Fuel Pump Status 4 - Primary Pump Low Duty

• Fuel Pump Status 9 – Primary Pump High and Secondary Pump ON

The Secondary Fuel Pump is only switched on when a certain Injector Duty is achieved (see the Fuel Pump Control section earlier in this manual for more information).

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The 2^nd Fuel Pump has been calibrated for stock 570cc injectors and the 2^nd pump will activate around 2500rpm on full load (34% Injector Duty) BUT when fitting larger Injectors (1000cc for example) then the same Injector Duty will be around 3800rpm meaning the 2^nd fuel pump switches on too late and the fuel rail pressure will start to as the Primary pump runs out of flow capacity!

So it is very important when fitting larger injectors that the Secondary Inj Duty% Threshold is reduced relative to the Fuel Injector size % increase otherwise the 2^nd Pump will switch on too late and the fuel rail pressure will drop (as shown in the following log file screenshot).

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In this example a Fuel Pressure sensor has been imported through the Boost Sensor #1 and the Fuel Pressure is shown in the Log File as Custom Map N Output. 

The GTR static fuel pressure at sea level is 4 bar (60psi), with 1 bar boost the fuel pressure should be 5 bar (75psi). During this power run you can see Boost Bank 2 climbing to 1 bar boost with the Fuel pressure climbing from 4 to 5 bar by 3000rpm but by 3500rpm the Primary pump has run out of capacity and rail pressure is starting to drop as low as 4.6bar during this dyno pull.

The 2^nd pump finally kick in 3900rpm (34% Injector Duty) and the fuel pressure increases from 4.6 to 5.2bar and is regulated back down to 5bar.

Fuel Rail Pressure dropping as the 2^nd Fuel Pump switches on too late!!

See Custom Maps manual for more information on importing pressure sensors and how to log and display on the setup Fuel Pressure sensor Fail Safes.

Ignition

Ignition TIming MODE1 to MODE4

The map specifies ignition timing in degrees BTDC based on Engine Speed (RPM) and Calculated Engine Load (%).

The latest phase 3 or 4 RRFF (ver.12738 or newer) does not use the complex factory Mode A and B Ignition maps. These maps can be found under the category IGNITION TIMING > FACTORY - NOT RECOMENDED if an older RRFF version is being used.

The factory ignition maps have been replaced by four larger and more simplistic to understand versions and a map is provided for each of the four map switch modes (Mode 1- 4).

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These superior Ignition maps offer the following advantages:

• Real Ignition Timing values.

• High-power high-resolution ignition maps rescaled for over 1000bhp.

• New 26x19 ignition maps provide 200% greater resolution than the stock 16x16 maps providing more accurate calibration at high RPM and high load.

• Up to 8000% more resolution over the stock Nissan map axis scaling providing unparalleled smoothness and drivability.

• Dynamic advance feature retained on Gen 2 models.