Torque Management for Toyota 70 Series LandCruiser

What is Torque Management?

Torque Management is a process of reducing the torque output of an engine during gear changes or fault scenarios that will provide improved longegevity of the Automatic transmission. This is especially important in highly modified high-torque output engines that exceed the OEM torque handling capacity of the AB60 transmission (720nm at the crank).

How can you implement Torque Management in a Manual 70 Series?

The factory manual 70 Series Landcruiser in both the 6 cylinder Turbo Diesel (HDJ7x) and the V8 Turbo Diesel (VDJ7x) already have a provision for reducing torque of the motor for a specific scenario. On the manual gearbox, there is a sensor to detect when the gearbox has been shifted into first gear. This sensor in turn triggers the Engine ECU to run a different map for the engine which has increased torque limitations. The only logical reason we can see the need for this, is for reducing load on the clutch and/or input shaft during standing start take offs, due to the tall ratio of first gear.

How does this apply to the Automatic Transmission Conversion?

We connect to the wiring used for this sensor so that our Transmission Control System - COMPUSHIFT - can activate this map during gear changes and in Failsafe environments for the Automatic Transmission. This ensures the automatic transmission shifts while the engine output is in a reduce torque state, reducing the slip of the clutches during gear changes. Once the gear change has been completed, the Transmission Control System deactivates this map and restores full power to the engine.

How is it connected?

In the main transmission harness that connects the COMPUSHIFT module to the transmission, there are two connectors that are connected to the OEM harness. One of these connectors will have a single wire that will be Yellow with Red Stripe. This wire comes from the COMPUSHIFT and is what triggers the torque management map. If this wire is disconnected, the ECU will be in permanantly in the torque reduction map.

Flash Tuning the Factory Engine ECU

Getting a Flash Tune of the Engine ECU is becoming common place and can provide great improvements to the engine output. However, with the manual 70 Series V8 ECU, it is common for this torque reduction map to be overwritten with a full power map. This may not cause an issue in the manual configuration, but we need this to be re-instated or not touched, when the automatic conversion is fitted. This is EXTRA important if the engine has been fitted with uprated injectors or larger turbo.

Our standard requirement is that the torque reduction map be maintained at the factory limits to ensure transmission longevity however, in some instances the difference between full power and the torque reduction map in the engine can be significant enough to cause drivability issues. In these situations, we ask that you work in conjuction with Wholesale Automatics Tech Support team to bring the torque reduction map and full power map closer together for an improved shift feel by making adjustments to the transmission calibration to allow for this increase in torque during gear changes. We ask this to avoid the chance of damage to the transmission as a result of the engine tune, which may affect a warranty claim.

For more information or to discuss options, contact Wholesale Automatics Tech Support via techsupport@askorto.com.au or call 03 9762 8004 opt 2.