How to Check Your Car’s BHP and Improve Performance
Brake Horsepower (BHP) tells you how much power your engine makes before the drivetrain steals a few ponies. More BHP means quicker acceleration, stronger towing, and sharper overtakes.
This guide shows:
- What BHP really measures
- Why it matters for tuning, fuel use and resale
- Three ways to check BHP at home or with a pro
- Easy mods that lift BHP without risking engine life
Free reg lookup: see your factory BHP
Check BHP
Pop in your plate and we’ll email the stock BHP figure plus common gains for a Stage 1 remap. No spam—just facts.
What is BHP?
BHP is the raw power an engine produces at the crank. It ignores drag from the gearbox, alternator or water pump, so it’s the best yardstick for engine health and tuning results.
Why bother checking BHP?
- Tuning proof: See real gains after a remap or intake swap.
- Fuel balance: Track power versus economy to avoid pointless mods.
- Buying advice: Compare two cars on more than badge and trim.
- Fault-finding: A big drop hints at blocked filters or worn injectors.
3 ways to measure BHP
1. Rolling-road dyno (external partner)
A dyno straps your car to motor-driven rollers and reads power through the rev range. It’s the gold standard for accuracy but needs specialist equipment and costs about £80–£150.
2. OBD-II live data (DIY)
Plug a Bluetooth reader into the 16-pin port under the dash. Open Torque or OBDeleven, find the “Calculated horsepower” PID, and do a full-throttle pull in third gear. Results are within ±10 % of a dyno—good enough for home checks.
3. Manufacturer spec
Check the owner’s manual or the lookup above. Handy for a baseline, but real-world numbers drift as engines wear or mods stack up.
Rolling-road vs OBD: quick comparison
| Feature | Rolling-road dyno | OBD-II pull |
|---|---|---|
| Accuracy | ±2 % | ±10 % |
| Cost | £80–£150 | £20 reader (one-off) |
| Setup time | 30 min | 5 min |
| Shows Wheel HP | Yes | No (engine estimate) |
Why BHP readings change
- Airflow: Dirty filters strangle power.
- Fuel quality: Cheap diesel cuts combustion energy.
- Engine wear: Lost compression equals lost BHP.
- Mods: Turbo, exhaust or ECU tweaks can add 20–40 %.
Easy ways to add safe BHP
Remap: A Stage 1 software tune unlocks extra boost and better fuelling—often 25–35 % more power on a turbo diesel or petrol.
Cold air intake: Cooler, denser air feeds the cylinders for a small bump without major work.
Freer exhaust: Less back-pressure means faster spool-up and stronger mid-range pull.
Want instant answers? Use our remap calculator to see potential gains for your reg.
Already tuned? Run another BHP check and confirm the numbers.
Key takeaway
Check BHP once a year or after any mod. You’ll spot hidden problems early and prove the gains you paid for.
