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 uses 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 catalysts removed. 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 they do not give an output identical to the input, and it is different between each bank, and they 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).

NOTE: As the AFR logging parameters will generally read leaner than the actual AFR the vehicle runs we advise that a wideband sensor should always be used for accurate calibration.

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. 

Per Cylinder Fuel Trim

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 choose at least 800cc plus size injectors.

EcuTek can supply the high quality Bosch Motorsport Injectors that are 1050cc (good for 1000+bhp) and they are tried and tested and they do not suffer from 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.

Ignition Timing IAT Comp

This map should be used to advance and retard the Ignition timing based on Intake Air Temperature, it should also be used when running a ‘blow through’ MAF setup when IAT measures Charge Air Temp or when Speed Density is enabled.

Knock Control Enable Cold – Warm - Safe

This map can be used to turn the knock control ON/OFF at different RPM/Engine Loads when the engine is cold (below 60 Deg C), warm (above 81 Deg C) or in Safe mode. See RaceROM maps below for better control.

Knock Control Enable 

These maps are available for Phase 4 RRFF (version 14389 or newer), they can be used to turn the knock control ON/OFF in each of the different map switch modes and they replace the factory OEM maps shown above.

Knock Sensitivity

This per cylinder threshold map is the point where knock correction will become active for each cylinder. If the values against RPM are breached then the knock correction parameter will start to show knock retard. 

Built engines often generate excessive engine noise that can be detected as knock, raising these values will help prevent this being detected as knock though care must be taken that the sensitivity will still show true knock! The centre two cylinders are noisier due to cylinders either side (1-3 or 46) so the noise thresholds are higher.