VIRTUAL TORQUE

The Virtual Torque window is used to configure torque management on GM vehicles with Gen 4 and Gen 5 controllers. In these controllers, torque management is designed to protect the transmission by setting limits on how much torque the engine can deliver. However, this can be a concern to some tuners because it may limit the amount of power delivered by performance modifications.

CAUTION: Boosting the limits set here reduces the ability of the vehicle to protect its transmission. Proceed at your own risk. NEVER configure these tables to handle more torque than the engine will actually produce.

The window displays a series of tables, each of which correspond to an amount of spark advance or retard. When the engine is running, the ECM will use the table closest to the amount of spark advance employed at the moment.

The X-axis of these tables is rpm. The Y-axis is either cylinder airmass (in mg) or manifold air pressure (in kPa), depending on what is selected in the Table Group dropdown.

CONFIGURING A TABLE GROUP

NOTE: Since manifold air pressure and airmass are key inputs to these tables, it is important that Virtual VE tuning be complete and as accurate as possible before you begin. Without accurate input, achieving a good output is highly unlikely.

1.

Use the Table Group dropdown to select the group of tables to be modified.

2.

Edit the tables in the group as needed.

3.

Click Extrapolate Coefficients.

4.

Click Calculate Torque Tables.

EDITING THE TABLES IN TANDEM

Because the displayed tables perform the same function at different levels of spark advance, you may wish to make similar changes to all of them at the same time. VCM Editor helps you do this by providing the Link Selections checkbox.

When Link Selections is checked, selecting a cell or group of cells in one table will select the same cell(s) in the other tables. Changes made to the selected cells will then apply to all tables.

TABLE GROUP

There are several different versions of the virtual torque tables. Select a table group here to specify which version of the tables is displayed to the right. There are two basic table groups:

￭

Airmass. In this group of tables, the Y axis is cylinder airmass (in mg)

￭

MAP. In this group of tables, the Y axis is manifold air pressure (kPa)

Additionally, there is an E85 version of each table group. These tables will be used if the vehicle is configured for flex fuel applications and has been filled with E85 (high ethanol content) fuel.

There is also a DoD version of each table group. In vehicles that support Displacement on Demand, these tables will be used when cylinders have been deactivated.

Y AXIS MIN, MAX, AND INCREMENT

These fields configure the Y-axis labels for the table group selected above.

CAMSHAFT ANGLE

On VVT vehicles, a separate version of each table group can be configured for each CAM angle combination. Select a combination of intake and exhaust cam angles to configure the table group used for that combination.

On fixed cam (non-VVT) vehicles, these can be left at 0.

SPARK ITERATIONS

These fields configure the amount of spark advance or retard that each of the tables is keyed to.