While many standard components in the Nissan R35 GT-R may be replaced to achieve better performance, some combinations are more likely to deliver improvements with minimal retuning of the MoTeC ECU.
In general, factory fuel injection components will be suitable for improved performance, however, when the capabilities of these parts reach their limits, e.g, inadequate injector flow, it is necessary to replace them with higher performance alternatives.
It is our recommendation that components are chosen from our list of suitable options when selecting alternate parts.
Each component listed below includes the settings which should be adjusted or checked with M1 Tune. Clicking on these settings within M1 Tune displays operational help relevant to the item.
COMPONENT MODIFICATION SETTINGS
Current MoTeC injector calibrations are performed with a reference fluid which closely models unleaded gasoline. If fuel formulations such as E85 are used where the density is dramatically different to conventional gasoline, it may be necessary to recalibrate injectors to suit such fuel. In most cases, however, it is sufficient to make the following setting adjustments :
- Fuel Density Reference
- Fuel Density Temperature Coefficient
- Fuel Stoichiometric Ratio
- Fuel Molar Mass
Standard fuel injectors flow 600cc/min at 3 bar fuel pressure. Suitable replacements are:
- ID1000 injectors – 1000cc/min at 3 bar. Fully calibrated for M1.
- Siemens Deka 110333 (2315cc/min at 3 bar). This option requires extra spacing for the fuel rail but otherwise fits under the OE manifold.
For primary injector the settings adjusted are (where ‘x’ is the cylinder number) –
- Fuel Cylinder x Primary Injector Linearization
- Fuel Cylinder x Primary Injector Minimum Volume
- Fuel Cylinder x Primary Injector Reference Flow
- Fuel Cylinder x Primary Injector Reference Pressure
For secondary injector the settings adjusted are (where ‘x’ is the cylinder number) –
- Fuel Cylinder x Secondary Injector Linearization
- Fuel Cylinder x Secondary Injector Minimum Volume
- Fuel Cylinder x Secondary Injector Reference Flow
- Fuel Cylinder x Secondary Injector Reference Pressure
The above settings must also be adjusted for cylinders 2 to 6.
- Fuel Injector Peak Current
- Fuel Injector Hold Current
- Fuel Injector Peak Time
- Fuel Injector Off Time
- Fuel Injector Pin Drive
If a secondary set of injectors are fitted higher in the inlet manifold runner, the following settings are required to enable the use:
- Fuel Timing Secondary
- Fuel Injector Secondary Contribution
Turbo and Wastegate
Any suitable turbo and wastegate combination may be used, however, the following M1 ECU settings must be adjusted to optimise performance:
- Boost Filter
- Boost Activate
- Boost Margin
- Boost Maximum
- Boost Hysteresis
- Boost Aim Main
- Boost Control Feed Forward
- Boost Control Proportional Gain
- Boost Control Integral Gain
- Boost Control Derivative Gain
- Boost Actuator Polarity
- Boost Actuator Minimum
- Boost Actuator Maximum
- Boost Actuator Output Frequency
Standard throttle bodies have been used in engines delivering up to 1500 HP. We suggest retention of standard throttle bodies. The M1 throttle model is a characterisation of the flow characteristics of the throttle body and recalibration is not easily performed by the installer, dealer or tuner.
A replacement fuel pump is recommended as the standard pump may be inadequate. The M1 package allows for PWM control of an external fuel pump (via a suitable driver device such as MoTeC Dual Half Bridge – DHB). The following M1 ECU settings must be adjusted to reflect such a change:
- Fuel Pump External Output Frequency
- Fuel Pump External Polarity
- Fuel Pressure Control Default
- Fuel Pressure Control Over Pressure Margin
- Fuel Pressure Control Feed Forward
- Fuel Pressure Control Proportional Gain
- Fuel Pressure Control Integral Gain
- Fuel Pressure Control Integral Minimum
- Fuel Pressure Control Integral Maximum
- Fuel Pressure Control Derivative Gain
Inlet Manifold or Plenum Chamber
The stock manifold may have horsepower limits, and numerous aftermarket devices are available. M1 ECU settings must be adjusted to optimise performance:
- Inlet Manifold Volume
- Inlet Manifold Time Constant
Alternate intercoolers may be used. Cross-flow types are not recommended. Tuning adjustments may only be required if airflow changes significantly.
MAF (Mass Air Flow) Sensor
The standard MAF sensor provides adequate measurement range up to 650 HP (480 kW). If the standard sensor is placed in a larger diameter housing it is necessary to adjust the sensor calibration. The calibration can be approximated by using the squared ratio of cross-sectional areas of the original housing and the replacement housing.
Standard housing is 64mm, new housing may be 80mm
Ratio would be 80/64 = 1.25
Squared Ratio would be 1.5625 (that is, 56% more flow at a given voltage reading)
For best accuracy the sensor should be physically calibrated.
The following M1 ECU settings must be adjusted to reflect such a change:
- Airbox Mass Flow Bank 1 Sensor Calibration
- Airbox Mass Flow Bank 2 Sensor Calibration
Boost and MAP sensors
The stock boost sensor has a range to 270kPa absolute, that is, 1.7 bar or 25lbs of boost. If higher boost levels are achieved, the boost sensor can be replaced with another which has a higher range. Boost sensors may only need to read down to 100kPa absolute. M1 ECU settings must be adjusted to reflect such a change:
- Boost Pressure Bank 1 Sensor Calibration
- Boost Pressure Bank 2 Sensor Calibration
- Boost Pressure Bank 1 Sensor Voltage Filter
- Boost Pressure Bank 2 Sensor Voltage Filter
The stock MAP sensor may also be changed, however replacement MAP sensors should be capable of reading down to 20kPa. The following M1 ECU settings must be adjusted to reflect such a change:
- Inlet Manifold Pressure Bank 1 Sensor Calibration
- Inlet Manifold Pressure Bank 2 Sensor Calibration
- Inlet Manifold Pressure Bank 1 Sensor Voltage Filter
- Inlet Manifold Pressure Bank 2 Sensor Voltage Filter