PerfectPower vs Harry's Dyno
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
PerfectPower
This app provides professional-grade automotive power and performance measurements using your smartphone's sensors. It offers unparalleled accuracy and a wide range of features for measuring acceleration, speed, power, and torque, all without external equipment.
- Measure engine power (DIN, CEE, SAE, JIS, ISO)
- Measure performance (accelerations, speed, braking)
- Simulate performance metrics
- Calculate gearbox ratios
- Measure lap times on track
- High accuracy sensor combination
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PerfectPower is, in the form of a revolutionary smartphone application, the automotive reference on-board system in power and performance measurements, the one with the best price / reliability of results / variety of features / operational independence ratio! Indeed: 1) Exceptional and unprecedented results reliability for a smartphone application, comparable to that of professional equipments, since it measures acceleration, speed, and distance with an accuracy of +- 0.5%, and power and torque with an accuracy of +- 1%! For information, a friendly challenge of 10,000 euros & dollars was launched on this subject on May 1, 2024, which is still waiting to be taken up… Note: Such accuracy is made possible by the accurate, permanent, and clever combination of the information of the accelerometer and the GPS of the phone, knowing how to take the best of both sensors while eliminating the specific disadvantages when used individually. 2) Unprecedented features variety not only for a smartphone application but also all equipments combined, since it allows to: - Measure the standardized engine power (DIN, CEE, SAE, JIS, ISO) - Measure the performance (accelerations, runs flying start, max speed, braking -soon available-) - Simulate the performance (accelerations, runs flying start, max speed, ideal max revs) - Calculate gearbox ratios by rev calibration (as on chassis dynamometer) (soon available) - Measure freewheeling losses (soon available) - Measure lap times on track Of course, as its name suggests, PerfectPower specialized in power measurements, which are the most interesting measurements of all in Automotive Physics! 3) Total operational independence, since it requires absolutely no connection to any external equipment (external GPS, car ECU, etc), which allows it to operate on 100% of the cars produced on the planet, and with only your smartphone as a measuring instrument! This does not prevent it from accepting communication via Bluetooth with certain high-performance external GPS in order to further optimize its results accuracy! 4) It only costs… 33 euros & dollars (27 currently), when: - a chassis dynamometer (professional power measurement tool) costs between 30,000 and 120,000 euros & dollars! - a simple pass on such equipment is charged 50 to 120 euros & dollars (without guarantee of maximum reliability!) - an optical reading system (professional performance measurement tool) costs around 15,000 euros & dollars! Of course, there are a certain number of rules to follow to achieve optimally accurate measurements (the most important being to perform measurements in both directions of the road -and on the same portion- and to ask PerfectPower to average them in order to eliminate the effects of road slope and wind), but when these rules are well followed, PerfectPower has proven that: - It was as accurate for power measurements as the best chassis dynamometers (Rotronics -France-, Maha -Germany-, DynoJet -USA-) - It was as accurate for acceleration measurements as the best external GPS, the RaceBox Mini - It was significantly more accurate than any other smartphone application in the field All information about this awesome application on its official website www.perfectpower.pro
Harry's Dyno
Measure vehicle performance with high precision using GPS and OBD sensors. Test acceleration and deceleration across custom speed ranges, analyze detailed results, and store data locally. Supports external sensors for enhanced accuracy.
- GPS and OBD sensor integration
- Custom speed range testing (acceleration/deceleration)
- Detailed results analysis
- Two-cursor data inspection
- Local data storage and filtering
- Data export to various formats
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Harry's Dyno is a high precision performance measuring app. It utilizes GPS and OBD sensor input to recognize arbitrary speed ranges like 0-60 mph or 100-200 km/h. Both acceleration and deceleration testing is supported. Results can be compared and analyzed in details. Using two-cursor mode, one can inspect subranges of data recorded (e.g. 80 to 120 km/h for a 0 to 200 km/h). Data is stored locally and can be filtered by speed range and vehicle used. It can be exported to various data formats too. Provided the smartphone is mounted in a position with good GPS accuracy, the internal GPS can be used for measurements. For short speed ranges, high powered vehicles, and highest precision, either external GPS or OBD sensors can be connected. OBD adapters are actually preferable as speed changes are available instantly. We have an always up to date list of compatible accessories available here: www.gps-laptimer.de/compatibility/ios For distance based performance testing (quarter mile etc), please use Harry's LapTimer currently. This mode will be added to Harry's Dyno as a free upgrade shortly. For Harry's LapTimer users! Harry's LapTimer GrandPrix has received a free feature upgrade and includes Harry's Dyno functionality now: please follow LapTimer ‣ Race ‣ Performance to use the dyno mode. In case you have used Harry's LapTimer Petrolhead so far, you may either upgrade it to GrandPrix (LapTimer ‣ Administration ‣ Add-ons), or go for Harry's Dyno as a separate app. Enjoy and let us know what you think! For questions, tipps & tricks, and support, please use our forum www.gps-laptimer-forum.de
Screenshots
Verdict
The clearest difference is review sentiment: PerfectPower at 95% against Harry's Dyno's 0%. Harry's Dyno's advantage is price ($3.99 vs $33.00). On update cadence, ads, in-app purchases and monetization model there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
PerfectPower costs $33.00 and Harry's Dyno $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.
PerfectPower ships an update every 2 months, Harry's Dyno every 3 months. Both last shipped on October 24, 2026.
| Parameter | PerfectPower | Harry's Dyno |
|---|---|---|
| Price | $33.00 | $3.99 — better |
| Rating | — | 1.0 (2 ratings) — better |
| Positive reviews | 95.0% of reviews — better | 0.0% of reviews |
| Number of ratings | — | 2 — better |
| Update frequency | Every 2 months — better | Every 3 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPod | iPhone, iPod |
| Requires iOS | 12.0 | 12.0 |
| Further details — not scored | ||
| Size | 3 MB | 41 MB |
| Age rating | 4+ | 4+ |
| Developer | La maison de Spinoza | Harald Schlangmann |
Customer experience
PerfectPower
Harry's Dyno
In-app purchases
PerfectPower
No in-app purchases
Harry's Dyno
No in-app purchases
Questions
Is PerfectPower free?
Is Harry's Dyno free?
Do PerfectPower or Harry's Dyno have ads?
Which is updated more often, PerfectPower or Harry's Dyno?
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