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Unit Conversion
Cole Gentry edited this page Dec 23, 2025
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1 revision
UltraLog provides comprehensive unit conversion for 8 measurement categories. This page details all available options and conversion formulas.
- Access unit settings via the Units menu
- Changes apply immediately to all displayed values
- Original data is never modified - conversions are display-only
- Preferences are maintained for the session
| Unit | Symbol | Description |
|---|---|---|
| Kelvin | K | SI base unit |
| Celsius | °C | Metric standard |
| Fahrenheit | °F | Imperial standard |
Celsius = Kelvin - 273.15
Fahrenheit = (Kelvin - 273.15) × 9/5 + 32
- Haltech: Stores temperature in Kelvin
- ECUMaster: Typically in Celsius
- Speeduino: Varies by configuration
- Coolant Temperature
- Intake Air Temperature (IAT)
- Oil Temperature
- Exhaust Gas Temperature (EGT)
- Fuel Temperature
| Unit | Symbol | Description |
|---|---|---|
| Kilopascals | kPa | SI standard |
| PSI | psi | Pounds per square inch |
| Bar | bar | Metric bar |
PSI = kPa × 0.145038
Bar = kPa × 0.01
- Manifold Absolute Pressure (MAP)
- Boost Pressure
- Oil Pressure
- Fuel Pressure
- Barometric Pressure
| kPa | psi | bar | Condition |
|---|---|---|---|
| 101.3 | 14.7 | 1.01 | Atmospheric (sea level) |
| 50 | 7.25 | 0.5 | Vacuum (naturally aspirated) |
| 150 | 21.8 | 1.5 | ~7 psi boost |
| 200 | 29.0 | 2.0 | ~14 psi boost |
| 250 | 36.3 | 2.5 | ~21 psi boost |
| Unit | Symbol | Description |
|---|---|---|
| Kilometers per hour | km/h | Metric standard |
| Miles per hour | mph | Imperial standard |
mph = km/h × 0.621371
- Vehicle Speed
- Wheel Speed (individual wheels)
| Unit | Symbol | Description |
|---|---|---|
| Kilometers | km | Metric standard |
| Miles | mi | Imperial standard |
miles = km × 0.621371
- Trip Distance
- Odometer
- GPS Distance
| Unit | Symbol | Description |
|---|---|---|
| Liters per 100km | L/100km | Metric (lower is better) |
| Miles per gallon | MPG | Imperial (higher is better) |
MPG = 235.215 / L/100km
Note: These units are inversely related - L/100km measures fuel consumption while MPG measures fuel efficiency.
| L/100km | MPG | Efficiency |
|---|---|---|
| 5 | 47 | Excellent |
| 8 | 29 | Good |
| 12 | 20 | Average |
| 15 | 16 | Poor |
| 20 | 12 | Very Poor |
| Unit | Symbol | Description |
|---|---|---|
| Liters | L | Metric standard |
| Gallons | gal | US gallon |
gallons = liters × 0.264172
- Fuel Level
- Fuel Used
- Tank Capacity
| Unit | Symbol | Description |
|---|---|---|
| Liters per minute | L/min | Metric standard |
| Gallons per minute | GPM | Imperial standard |
GPM = L/min × 0.264172
- Fuel Flow
- Air Flow
- Water/Coolant Flow
| L/min | GPM | Approximate Power (gasoline) |
|---|---|---|
| 0.5 | 0.13 | ~100 HP |
| 1.0 | 0.26 | ~200 HP |
| 1.5 | 0.40 | ~300 HP |
| 2.0 | 0.53 | ~400 HP |
Note: Actual power depends on BSFC and other factors
| Unit | Symbol | Description |
|---|---|---|
| Meters per second squared | m/s² | SI standard |
| Gravitational force | g | Earth gravity reference |
g = m/s² / 9.80665
| m/s² | g | Context |
|---|---|---|
| 9.81 | 1.0 | Earth gravity |
| 4.9 | 0.5 | Moderate acceleration |
| 9.8 | 1.0 | Hard braking/acceleration |
| 14.7 | 1.5 | Very hard maneuver |
| 19.6 | 2.0 | Extreme (racing) |
- Longitudinal G (acceleration/braking)
- Lateral G (cornering)
- Vertical G (suspension movement)
UltraLog uses these defaults:
| Category | Default |
|---|---|
| Temperature | Celsius |
| Pressure | kPa |
| Speed | km/h |
| Distance | km |
| Fuel Economy | L/100km |
| Volume | Liters |
| Flow Rate | L/min |
| Acceleration | m/s² |
- Raw Data - ECU logs data in native format
- Parser - Converts to base units (Kelvin, kPa, etc.)
- Storage - Data stored in base units
- Display - User preference conversion applied
- Legend - Shows converted value with unit symbol
Haltech logs coolant temp as 363.15 (Kelvin)
→ Parser reads raw value: 363.15 K
→ Stored in memory: 363.15 K
→ User preference: Celsius
→ Displayed: 90.0 °C
→ If changed to Fahrenheit: 194.0 °F
Using base units internally:
- Ensures consistency across ECU formats
- Simplifies conversion logic
- Prevents cumulative rounding errors
- Allows instant unit switching
- Use units familiar to your region/industry
- Match units to your reference documentation
- Consider your audience if sharing exports
- Use the same units when comparing logs
- Note that some ECUs log in different units
- Field Normalization helps standardize naming
If values seem wrong:
- Check your Unit Preferences
- Verify the ECU's native units
- Some channels may not support unit conversion
- User-Guide - Complete feature reference
- Field-Normalization - Channel name standardization
- Supported-ECU-Formats - ECU-specific information
Links