Tuning Your TCM

Benefits of TCM Tuning

Transmission tuning is sometimes seen as a dark art or an unnecessary extra cost, here at EcuTek we feel that it should be given the respect that’s due, not only for 1000+bhp cars but any tuned vehicle. With ever increasing inter-module integration and new more advanced control strategies precise tuning of both ECM and TCM is required. Without this careful approach the risks of engine and gearbox damage increase and drivability can suffer.

It may not feel like there is much added value with a TCM tune however now with the latest features and understanding TCM tuning improves aspects like,

• Gear change torque reduction, (could save gearboxes on big HP cars and helps reduce clutch wear on less intense tunes.
• Maximum clutch pressures (allows for increased clutch clamp pressure preventing clutch slip)
• Extra data, in some cars like GTR the TCM gets CAN bus information and transfers it to the ECM meaning that the ECM wont be able to use some features when the TCM is not tuned.
• Changed shift points to improve each driving mode the car is using
• Allows you to accommodate gearbox upgrades appropriately
• Shift limits, these give you the ability to raise the gearbox rev limits and speed limits for cars with higher than stock rev limits.
• Allows smoother or more aggressive shifts to be set up

Achieving these improvements with EcuTek software is done using RaceROM custom code as well as the OEM maps keeping the drive as close to stock as possible.

Gear change torque

Now days every GTR has 1000hp and the same amount of torque, the OEM calibrated maps do not apply any more percentage reduction after 600NM of torque (stock amount), if your car produces 1000nm of torque when the torque reduction of 60% (adequate for 600NM) is applied there is still 600Nm of torque left smashing the clutches and shifting excessively hard or not shifting at all (abandons the shift).

Gear Change Torque

Each gear change torque map (per mode per gear) can be modified to better suit the higher output torque and achieve shifts in high power cars that won’t damage the gearbox or clutches.

Maximum clutch Pressures

Using a series of maps and some RaceROM code we can successfully increase the desired clutch pressure, while not necessary on a standard car high power vehicles may want to increase this to prevent the clutch slipping in lower gears.

Max Clutch Pressure (RaceROM)

Extra data

To allow the ECM the full range of features and map switch display on the Dash the RaceROM code to send extra data can be enabled

Extra Data

Changed Shift points

With different final drives or different driving styles the shift points may want to be moved from their standard rpm / vehicle speed. This can be done by changing the appropriate corresponding map in the ROM.

Shift points

Shift points

There is an excel Sheet attached that tuners can use to visualise the vehicle speeds and resulting RPM of the set shiftpoints in each mode

Gearbox hardware upgrades

As more aftermarket transmission components become available from reputable companies such as Dodson, Sheptrans, Jack transmissions and Levelten calibration is required to maximise the gains such as increased pump capacity improved fiction material, changed ratio’s, shift forks and solenoids, pressure sensors and Final drives. Just like upgrading parts on the engine they need to be incorporated in the tune to get the maximum out of them or to get them to work at all.

Shift limits

Its common to increase the rev limits of your vehicle, however, the gearbox will deny a shift before the engine rev-limits are reached if not tuned correctly, these can easily be adjusted in the shift limit maps.

Shift limit map

Smoother shifts

If you envy the smooth shifts of the late model GTR it can be achieved by calibration of the TCM, it starts with clutch friction coefficients and accurate torque estimation. If the ECM is tuned correctly and the clutch capacities and coefficients are correct, incredibly smooth shifting can be achieved.

Clutch Friction Coefficients

Hopefully this give you a good idea of the sorts of things that can be achieved by tuning the TCM, there are more features that we can leave to your tuner to explain. Enjoy the smooth responsive reliable drive that a good TCM tune can deliver.