What torque management actually does
Think of torque management as a very fast closed loop traction system built around a speed curve you draw yourself. You tell the ECU what driveshaft RPM, engine RPM or both should look like at each point in the run. While the car stays on or under that curve, nothing happens. The moment the controlled speed climbs above target, the ECU takes torque away, first by pulling ignition timing and, if that isn't enough, by dropping individual cylinders. As soon as the speed falls back into line, power comes back.
Because it reacts within firing events rather than waiting on the driver, it can catch tire shake and wheel spin before they turn into a lost run. You can add further torque reduction outside this function by lowering boost or holding back a nitrous stage, but the ignition and cut control live here.
Torque management only ever subtracts. Whatever your tables say, the final timing can't go past the ignition base map. If you have timed retards running from another function and the car falls below its RPM target, torque management is allowed to cancel some of that retard, but it still can't push timing above base.
Which hardware supports it
This is a drag racing feature and it isn't on every Elite. You need one of these:
- An Elite 2500 T (see the Elite 2500 T overview).
- An Elite VMS T (see the VMS / VMS T overview).
- A standard Elite 2500 paired with the Race Expansion Module, which must be talking to the ECU over Haltech CAN for the function to work.
For a driveshaft-based strategy you'll also want a proper driveshaft RPM sensor, such as a magnet collar like the 2.125 in split collar pickup (other sizes are available to suit your shaft).
Wiring tab: arming and extras
How it gets armed
| Arm Method | Behavior | When we use it |
|---|---|---|
| Always on | Active any time the function is enabled | Bench testing, or cars that only ever see the strip |
| Switch | A driver switch turns it on and off | Dual-purpose cars that also get driven on the street |
| Race Timer | Works off a configured race timer, usually started by transbrake or clutch release | The normal choice. Targets get mapped against Race Time |
Armed Output Enable adds an output you can wire to a dash LED so the driver knows the system is live before staging. A DPO or stepper output is the usual pick.
Torque Management Knob Enable adds an input for a rotary trim knob. With the knob used as an axis in your target tables, the driver or crew chief can pick between up to eight curves in the staging lanes when the track has tightened up or gone away since the last pass. The 12-position rotary trim module is the part we reach for, and the rotary trim module article covers wiring. The knob calibration itself is loaded or saved on the Knob Calibration tab, and several calibrations ship with ESP.
Input settings for the switch and knob
The arm switch normally goes on an analog voltage input (AVI). The knob can use an AVI or a synchronized pulsed input (SPI).
- On an SPI: set the edge to Falling if the switch pulls the input to ground, or Rising if it feeds the input voltage. Sensor Type is Hall Effect for switch inputs, and turn the pullup on if the input needs one to see a voltage when the switch is open.
- On an AVI: you give the ECU a Switch On and a Switch Off voltage, and leave a gap between them so electrical noise can't make it chatter.
A quick worked example: a switch that idles at 5 V and grounds to 0 V when pressed works nicely with On at 0.5 V and Off at 4.5 V. A switch that sits at 2.5 V off and jumps to 12 V on could use On at 4.5 V and Off at 3.0 V. The wide band between the two thresholds is your noise margin.
Settings tab
| Setting | What it does | Our advice |
|---|---|---|
| Controlled Variable | Picks the speed being policed: driveshaft RPM (via the vehicle speed driveshaft sensor), engine RPM, or both | Driveshaft RPM is the truer measure of what the tire is doing. Add engine RPM if you also want to catch converter or clutch flare |
| Cut Method | How cylinders get dropped once retard alone can't hold the target: None, Ignition, Injection, or Ignition and Injection | Ignition cut is the common choice. Injection cut isn't offered on the VMS T |
| Height Ignition Correction Enable | Turns on a timing retard table driven by front ride height or shock travel | Worth it on cars that carry the front wheels |
If you control both RPM sources at once, the ECU applies the larger of the two percentage cuts and adds the two ignition corrections together. Keep that in mind so you don't double up on retard by accident.
The tables, and how to fill them
All of these live under ECU Navigator > Torque Management. The usual layout is Race Time across the x axis and the knob position up the y axis, but you can assign any channel. Press F3 with a table selected to edit its axis. Changing an existing breakpoint rescales the table so its shape is kept.
RPM Target (driveshaft or engine)
This is the curve the car is supposed to follow. Target error is actual speed minus target, so a positive error means the car is going faster than planned, which on a drag car nearly always means the tire is letting go.
Don't guess this curve. Pull driveshaft and engine RPM from logs of good passes, or make a run with the function disabled and log it, then use that trace as your first target. Start with a single knob row, say position 5, and only fill in the other rows once that one works. After that, spread them out so the top position is your best-ever track and the bottom is a slick, cold lane.
Timed IgnCorr
A planned retard against time. It lets the car leave hard, get on top of the tire, then trims timing through the zone where it usually spins, and feeds timing back as speed builds and the tire can take it. The goal is to make the feedback side do as little as possible. Log the Torque Management Combined Ignition Correction channel against Race Time and shape this table to match what the controller was already doing.
RPM Target Error Cut Offset
How far over target the car can get before the ECU starts dropping the next fuel or spark event (depending on the cut method). Once speed is back within this band, power returns from the next cylinder. It can be a single number or use up to two axes, for example knob and driveshaft RPM. Haltech gives 250 RPM as a typical value.
RPM IgnCorr
The feedback timing correction applied from target error. Make the controlled RPM one of the axes, which is strongly recommended. Race time, gear or engine RPM make good second axes, or turn the second axis off. The table may show advance where the car is under target, which can cancel planned retard, but the overall result still can't exceed base timing.
Height IgnCorr
Pulls timing when the front end climbs, using ride height or shock travel sensors such as the laser ride height sensor. It's part safety, part traction: a wheelstand costs time and can end badly.
How we approach tuning it
- Get the base engine tune right first. Torque management can't fix a bad fuel or timing map.
- Make a baseline pass with it disabled and log everything.
- Build one row of the RPM target from that log, and a mild timed correction.
- Set a cut offset and a modest error-based timing correction.
- Make passes, and move the timed table toward the combined correction you logged so the feedback side has less to do.
- Only then build out the other knob rows.
Channels to log
| Priority | Channels |
|---|---|
| Must have | Race Time (or your primary axis), Driveshaft RPM and its target, Engine RPM and its target, Engine Limiter Active, Torque Management Combined Ignition Correction |
| Strongly suggested | Torque Management Knob (or your secondary axis), Armed State, Driveshaft RPM Limit, Timed Ignition Correction, Target Error, Target Error Ignition Correction, Height Ignition Correction |
| General drag logging | Air and coolant temp, oil temp and pressure, fuel pressure, ignition angle, launch control input state, injector duty for every stage, manifold pressure, throttle position, trigger errors, wideband |
Troubleshooting
| Symptom | Usually |
|---|---|
| Nothing happens on the pass | Not armed: check the arm method, race timer start condition and the Armed State channel |
| Car goes flat and slow even with good traction | Target curve too low, or the timed correction pulls more than it needs to |
| Still spins before it reacts | Target too high, cut offset too large, or not enough error-based retard |
| Knob changes nothing | Knob not used as an axis in the tables, or wrong knob calibration loaded |
| Twice the retard you expected | Controlling both RPM sources, so the two corrections are being summed |
Related reading: launch control, torque model and Elite boost control.
Torque management FAQ
Is torque management the same as traction control?
They aim at the same problem, but torque management is built for drag racing: it follows a speed-versus-time curve rather than comparing driven and undriven wheels.
Can I use it on a plain Elite 2500?
Only with a Race Expansion Module connected over Haltech CAN. Otherwise you need a T-version ECU.
Where do I start with the target curve?
From your own logs. A good pass on your car on your tire is a far better starting point than any generic number. If you want a second set of eyes, book a free consultation with us.
