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GT-R TCM Tuning Guide

GT-R TCM Tuning Guide

Mar 09, 2020

 

 

GT-R ProECU Tuning Guide: TCM Supplement

 

Introduction

The Nissan GT-R TCM is at the heart of the GT-R driving experience and delivers excellent control of the Ricardo 6 speed dual clutch transaxle. The TCM controls the pressure applied to both of the clutches in the gearbox, while accurately positioning the selector forks to select gears in two gear clusters. The TCM is tightly linked to the ECM and together they deliver much of what makes the GT-R driving experience what it is.

An in depth understanding of the GR6 transmission can be had by comprehensive reading of the Nissan technical service manual that describes the mechanical operation, and many diagnostic functions and information. For detailed service and diagnostic information please refer to section TM “Transaxle & Transmission” in the Nissan R35 GTR service manual.

Some aspects of operation are useful to know in the tuning and calibration of the TCM maps to improve the driveability and/or performance to compliment power upgrades and transmission hardware changes. Understanding the live data and how to interpret it is an important step in successfully tuning the TCM.

 

 

Programming

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

For more software guides check out:

 

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.

Table of Contents

Supplemental Content

Platform Specific

 

General

 

 

 

 

 

 

Tuning Guide

 

 

 

Live data

A full list of live data parameters can be found in the service manual, however the most important ones are listed below.

  • Accel Position sensor 1 (%) - Actual Accel pedal driver input

  • Accel Position sensor 2 (%) - Effective Accel position including adjustment by (for example) cruise control

  • Clutch A Pressure (Bar) - Measured pressure on Clutch A Clutch A Slip (RPM) Engine RPM – Clutch A output RPM

  • Clutch A Speed (RPM) - Clutch A shaft RPM

  • Clutch A Pressure Target (bar) - Target pressure on clutch A the TCM control will try to maintain Clutch A Temperature (°C) Estimated temperature of clutch A based on friction, load and slip

  • Clutch B Pressure (Bar) - Measured pressure on Clutch B Clutch B Slip (RPM) Engine RPM – Clutch B output RPM 

  • Clutch B Speed (RPM) - Clutch B shaft RPM

  • Clutch B Pressure Target(bar) - Target pressure on clutch B the TCM control will try to maintain Clutch B Temperature (°C) Estimated temperature of clutch B based on friction, load and slip Engine Speed 1 (RPM) - Engine RPM

  • Engine Torque Available (Nm) - Estimated engine torque potential without any reductions active

  • Engine Torque Demanded (Nm) - Engine torque requested by driver, sent from ECM

  • Engine Torque Limit Request (Nm) - Torque request sent to ECM to cut power on upshift

  • Engine Torque Limit Request2 (Nm) - Torque request sent to ECM to limit push after downshift blip (when req)

  • Fluid Temperature (°C) - Bulk temperature of transmission fluid G Force Lateral (G) Lateral (left/right) G-Force from the G sensor

  • G Force Longitudinal (G) - Fwd/Rev G-Force as calculated from rate of change of vehicle speed

  • Gear Current - The Gear the TCM is actually in (may be different to display) Gear Desired The Gear that the TCM is trying to shift to

  • Gear Planned - The next gear that will be shifted into if requested (preselected next gear) Gear Indicator Gear as shown on the dash indicator

  • Line Pressure (Bar) - Main hydraulic system pressure

  • Mode (0 to 5) -  0=Auto, 2=Auto (Race), 3=Manual, 4=Manual(Race), 5=Snow/Eco

  • XXXX S/V Commanded (%) - Solenoid valve current commanded by TCM for various solenoids

  • XXXX S/V Monitored (%) - Solenoid valve current measured by TCM for various solenoids

 

 

Early Gen 1 TCM ROMs will log at approximately 10 Hz while the later ROMs such as the KJ series (both 1mb) log at 50hz. TCM logging speed is unaffected by the number of logging parameters enabled as all the data is returned no matter what the request.

 

EcuTek recommends the programming of all 2008-2010 TCMs with the latest KJ series ROMs as they offer a number of improvements, of which logging speed is just one, more detailed explanation of ROM choice is covered later in this manual.