Model stall ratio, slip, heat, and output power. Visualize performance across practical speed ratios clearly. Designed for transmission studies, diagnostics, sizing, and learning tasks.
The form uses a 3-column layout on large screens, 2 columns on medium screens, and 1 column on mobile devices.
The chart traces estimated torque ratio and efficiency against speed ratio, then highlights the current operating point.
| Scenario | Turbine Speed (rpm) | Speed Ratio | Torque Ratio | Turbine Torque (Nm) | Output Power (kW) | Efficiency (%) | Heat Loss (kW) |
|---|---|---|---|---|---|---|---|
| 1 | 600 | 0.250 | 1.717 | 465.92 | 29.27 | 36.40 | 51.15 |
| 2 | 1200 | 0.500 | 1.355 | 367.55 | 46.19 | 57.43 | 34.24 |
| 3 | 1800 | 0.750 | 1.086 | 294.51 | 55.51 | 69.03 | 24.91 |
Example assumptions use 320 Nm engine torque, 2400 rpm pump speed, 2.15 stall ratio, and the default efficiencies shown in the form.
1. Speed Ratio
Speed Ratio = Turbine Speed / Pump Speed
2. Slip
Slip = Pump Speed - Turbine Speed
Slip % = (Slip / Pump Speed) × 100
3. Torque Ratio Model
For speed ratios below the coupling point:
Torque Ratio = 1 + (Stall Ratio - 1) × (1 - Speed Ratio / Coupling Speed Ratio)Curve Exponent
For speed ratios at or above the coupling point:
Torque Ratio = 1
4. Effective Ratio
Effective Ratio = Torque Ratio × Hydraulic Efficiency × Mechanical Efficiency × (1 - Loss Fraction)
5. Power
Input Power = Engine Torque × Pump Angular Speed
Output Power = Turbine Torque × Turbine Angular Speed
6. Efficiency
Converter Efficiency = (Output Power / Input Power) × 100
7. Hydraulic Power
Hydraulic Power = Pressure × Flow Rate
8. Wheel Torque and Tractive Force
Wheel Torque = Turbine Torque × Gear Ratio × Final Drive Ratio × Driveline Efficiency
Tractive Force = Wheel Torque / Wheel Radius
It is the modeled multiplication between pump torque and turbine torque before downstream gearing. At stall, the ratio is highest. As speed ratio rises, the model smoothly drives the ratio toward one.
Near stall, the converter multiplies torque, but turbine speed remains low. Because output power depends on both torque and speed, the efficiency can stay modest even when torque gain looks strong.
It is the chosen speed ratio where the model stops applying torque multiplication and transitions to a near-coupling condition. Real converters vary, but values around 0.85 to 0.95 are common engineering assumptions.
Separating them lets you represent flow losses and mechanical drag independently. This is useful when comparing design ideas, test bench data, oil temperature effects, or alternate converter hardware.
No. Hydraulic power from pressure and flow is a supporting fluid-system metric. Transmitted output power comes from turbine torque and turbine speed. Comparing both values can still help diagnose thermal load and system behavior.
Use it to shape how quickly torque multiplication decays between stall and coupling. A higher exponent keeps torque gain elevated longer, while a lower exponent makes the transition more gradual.
Yes. Once turbine torque is calculated, the tool multiplies it through the selected gear ratio and final drive, then applies driveline efficiency and divides by wheel radius to estimate tractive force.
It is best for engineering estimation, screening, and education. For final validation, compare with converter maps, transmission dynamometer data, OEM test curves, and measured thermal behavior.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.