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 real horsepower, torque, and acceleration times — within 2% of a chassis dynamometer. 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 road. 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

- 2% accuracy compared to 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 option for pro-level precision: 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, data file, 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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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 road with no traffic
- External GPS (available as an in-app option) unlocks additional features: 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.

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.

Nope! After paying for the app and requesting customer support (twice which never materialized), I finally was able to download the app. I carefully followed calibration instructions, put in the gear ratios, vehicle weight including passengers, fuel level and "cargo", weather conditions, etc. Estimated 3rd and 4th gear Torque #'s were way off (much too high) for my stock BMW M240iX. Pushing to red line in higher gears should only be attempted on a closed course and there aren't any in my area.

What’s new

Major 2.4.0 update! 🚀

Brand new interface, and powerful new features:

- Complete new design — faster, cleaner, more intuitive
- Slope correction — accounts for uphill/downhill effects (external GPS)
- New image export — optimized formats for social media and print (Pro)
- External GPS — now available as a one-time purchase, or included with Pro
- Pro — now includes custom logo, data export & cloud backup

This update is the result of your feedback. Thank you to our community!