Torque setup and the torque maps

Get this right before anything else. The torque value the TCU sees drives line pressure, clutch fill, shift firmness, lockup and adaptation. Wrong torque is the number-one cause of slipping, burnt clutches and harsh shifts on an 8HP swap. Verify against the official manual and your own live data before you drive hard, this is a community guide, not a substitute for testing.

Why torque is the master input

The ZF 8HP is a fully torque-modelled gearbox. It has no line-pressure sensor; it infers pressure from solenoid current and sets that pressure from the engine torque it is told. So the torque value feeds, directly:

• Line (main) pressure — clutch clamping force. More torque commands more pressure so the packs do not slip. Idle line pressure is around 17 bar at 35°C.
• Clutch fill pressure and fill time — the oncoming clutch piston is pre-filled (~100 ms) before the shift. Fill scales from torque.
• Shift firmness — the engagement ramp targets a pressure band set by torque (roughly 0.6-1 bar light, up to ~6 bar at full load).
• Converter lockup — lockup clamp and slip allowance are torque-dependent.
• Torque reduction — how much cut the TCU asks the ECU for during a shift.
• Adaptation — the box only adapts in an 80-140 Nm window, and stores values against the torque it saw. Wrong torque means wrong learned values.

Two ways to get torque in

The Torque Calculation Input selector (category Torque Calculation) decides the source. The Automatic Detection of Torque Calculation Input flag falls back to internal calculation if CAN torque is lost.

CAN torque (from the ECU). OEM ECUs (e.g. Audi 5HP profile 20, BMW 6HP Exx profile 30) and some standalones put a torque value on CAN2 (engine bus, pins 66/67). The TCU reads it. Verify it. Tuned ECUs frequently report inflated torque (raised to dodge OEM torque limiters), so trim it with CAN Read Torque Multiplier and Offset Engine Torque.

Internal calculation (MAP + RPM + TPS). Most standalone and carb swaps. The TCU estimates torque from manifold pressure, RPM and throttle. Wire MAP to pin 7, TPS to pin 6, RPM to pin 65 (or feed RPM/MAP/TPS over CAN, e.g. Haltech profile 8 with the inputs set to the CAN engine channel) and set the input selector to internal.

The torque maps (firmware V10.75)

These are the actual tables in the XDF, category Torque Calculation:

(There are ft/lb mirrors of the base and max tables; use whichever unit set your map is in.)

What a base torque table looks like

This is the Base Torque Table RPM/MAP decoded from the BMW E90 Petrol 8HP70 base map (firmware V10.75). Columns are RPM, rows are manifold pressure (kPa), cells are estimated Nm. It is an example so you can see the shape, your engine and box differ, pull the right base map from download.turbolamik.eu and scale it to your torque curve.

Want to see this in your map? Open your .bin in the interactive map viewer, every one of the 314 tables, as a heatmap or an editable grid.

Setting it up

With CAN torque

1. Select the matching CAN profile and enable CAN2 (engine bus).
2. Watch the engine-torque channel live in TunerPro. At idle it should read roughly 10-20 Nm.
3. Hold 3000 and 5000 RPM unloaded, it should stay low (engine is not loaded).
4. Cross-check a known full-throttle figure against a dyno. If the ECU over-reports, pull it down with CAN Read Torque Multiplier (or Offset Engine Torque for a flat error).
5. Do not adapt until the value looks right.

Without CAN (internal calculation)

1. Wire and calibrate MAP (pin 7), TPS (pin 6) and RPM (pin 65). Power sensors from the 5V outputs.
2. Set Torque Calculation Input to internal.
3. Open Base Torque Table RPM/MAP. Note the value at 100 kPa (atmospheric). Scale the whole table by (your peak torque ÷ that value). Example: a 490 Nm engine showing 288 Nm at 100 kPa → ×1.70.
4. Turbo: fill in Base Torque Table MAP Correction so boosted torque matches reality.
5. Diesel: enable Use Table MAX TQ TPS Lim and build Max TQ TPS Lim (the MAP table is not usable without vacuum).
6. Verify idle reads ~10-20 Nm and the value tracks load sensibly. Do not adapt yet.

The danger: wrong torque

Too low (under-reported): line pressure too low → clutch slip in gear and during shifts → friction material polishes off → fluid contamination → heat. Lockup cannot hold zero slip → more heat. Adaptation learns values that are too soft for the real load.

Too high (over-reported): pressure too high → harsh, banging shifts and shock-loaded friction plates → accelerated wear. The TCU also requests bigger torque cuts than needed (a power dip on every upshift).

Either way, adapting with wrong torque is worse than not adapting — the box converges on wrong fill values and you cannot fix it by correcting torque afterwards. You have to correct torque, reset adaptations, then re-learn. See troubleshooting and the manual’s adaptations and internal torque calculation pages.

Common mistakes

• Adapting before torque is verified. The single most common cause of swap-box damage.
• Trusting a tuned ECU’s CAN torque without checking it against a dyno.
• Pointing RPM/MAP/TPS at the wrong input source (analog pins vs CAN channel).
• Fixing harsh shifts by raising shift firmness instead of correcting over-reported torque.
• Not resetting adaptations after changing the torque calibration.

Sources: the firmware V10.75 XDF (table names above), plus 8speed.au torque calculation, why torque matters, and HP Academy’s 8HP guide.