PerfExpert - Car Dyno HP Test

PerfExpert

In-app purchases

About this app

Know your car's true performance.

Turn your smartphone into a professional dyno. Measure the real horsepower and torque of your engine — within 2% of a chassis dynamometer — and time your car's acceleration. No OBD adapter, no cables, no expensive dyno sessions. Just mount your phone, accelerate, and get instant results.

Test and compare performance upgrades. Whether you're verifying an ECU remap, testing a new exhaust, or tracking the effect of a chiptuning session, PerfExpert gives you objective, independent data you can trust.

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HOW IT WORKS

1️⃣ Create your car profile
Enter your vehicle's weight, tire sizes, and gear ratios. Not sure about a spec? The app guides you through every step.

2️⃣ Mount your phone & accelerate
Secure your phone in the car — no connection needed. Find a flat, straight section on a closed track or private ground. Accelerate in one gear from low RPM to redline. That's it.

3️⃣ Get instant results
Power and torque curves appear immediately, just like on a real chassis dynamometer. Compare runs, track your modifications, and share results.

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MEASUREMENT MODES

🔴 Dyno — Full power & torque curves vs. engine RPM. Advanced drivetrain loss model, rev limiter detection, and correction standards (DIN, SAE, JIS, CEE, ISO). Results as detailed as a professional chassis dyno.

🟢 Timed Run — Measure acceleration from a standing start. Speed intervals: 0-100, 100-200, 80-180, 60-160 km/h — 0-60, 60-120, 50-110, 40-100 mph. Distance: quarter mile, eighth mile (with trap speed), 60 ft. Max speed and peak acceleration on every run.

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KEY FEATURES

- Only 2% average deviation from professional chassis dynamometers
- No OBD adapter or connection to your car required
- Works with your phone's built-in sensors
- External GPS available as an in-app purchase for pro-level precision with a compatible device (Dragy Pro, Lite, DRG70 · RaceBox Mini, Mini S, Micro): rolling start dyno, slope correction, free phone mounting
- Power correction norms: DIN, SAE, JIS, CEE, ISO — using real-time atmospheric pressure, temperature, and humidity
- Interactive charts: pinch to zoom, tap for exact values
- Export results as PNG image or shareable web link
- Custom units: HP, CV, kW for power — Nm, ft·lb, mkg for torque — km/h, mph for speed
- Works on phones and tablets

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PERFEXPERT PRO (optional subscription)

- Custom logo on your results
- Cloud backup of your results
- CSV data export

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WHO USES PERFEXPERT?

- Car enthusiasts who want to know their real HP and torque
- Tuners & mechanics verifying ECU remaps, chiptuning, intake, exhaust, or turbo upgrades
- Owners comparing before/after results of any modification
- Drivers timing their 0-60 mph or 0-100 km/h acceleration
- Anyone curious about their car's true performance

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IMPORTANT NOTES

- Dyno mode requires a manual gearbox or an automatic with manual/sequential mode
- For best results, use a flat, straight, horizontal section on a closed track or private ground
- External GPS (in-app purchase) unlocks additional features with a compatible device (Dragy Pro, Lite, DRG70 · RaceBox Mini, Mini S, Micro): more reliable results, rolling start dyno (no need to stop before measuring), automatic slope correction, and free phone orientation

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Sample dyno and acceleration reports:
https://app.perfexpert-app.com/results/featured

FAQ:
https://www.perfexpert-app.com/faq

Join the PerfExpert community:
https://www.facebook.com/groups/perfexpert/

Ratings and reviews

It's simple. Calibration may take couple tries if you do it wrong. I guess calibration pictures in the app could benefit from written words what's up and down, front and back. One of the pictures can be a bit of a guess. After that? You put the data, ACCURATELY. Stop the car, have the phone secure at acceptable position. Which is easiest thing in the world to do. You get green light, you drive. And results shown are very accurate, I've tested it on plenty of cars. Great app.

cant use the app at all. I get all the way to atmospheric conditions then nothing.

Tried several times and just can't get it to complete a session. There's allot of good features, and it should be quite accurate, but with the calibration taking a good 4 or 5 tries to complete, and the barrage of steps you have to go through before you can start a logging run (most of which can and should be automated) When you finally get to test it. You get successive error messages, phone in bad position, or phone at wrong angle, or travels distance less than 18m I've tried several times in multiple positions, and watched all the tutorials, but it's just too temperamental. It could be so good, but with the gauge error messages you get, I don't know how it wants to be positioned or what's wrong. Of a good 6 or 7 times testing on the asphalt, I've had 0 success in even getting it complete 1 run. It could be good, but it is just too temperamental, and too long winded to use.

What’s new

- The Dragy DRG70 is now supported as an external GPS device
- Internal sensors: car heading changes are now allowed after initialization, until the dyno run starts
- Metric horsepower is now labelled PS instead of cv
- Slope correction: more accurate corrected results
- User interface improvements, more complete translations and bug fixes

Thanks for your feedback!