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

Fuel Formulation

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

Fuel Injectors

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

High/Low Injectors

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

Throttle Bodies

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.

Fuel Pump

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

Intercooler

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.

For example:
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

Modifications Guide