# Compression Calculator vs PowerVision 4

The clearest difference is review sentiment: PowerVision 4 at 78% against Compression Calculator's 0%. PowerVision 4 also leads on rating (4.9 vs 3.0) and ratings volume (312 vs 3). Compression Calculator's advantage is in-app purchases (none vs 8) and update cadence (every 9 days vs monthly). On price, ads and device support there is nothing between them.

Both are free to download. PowerVision 4 sells 8 one-off in-app purchases. Compression Calculator asks for nothing beyond the download.

PowerVision 4 holds the better App Store score, 4.9 against 3.0. That said, the two scores are not equally well evidenced: PowerVision 4 has 312 ratings behind it against 3, so its average is the more settled of the two. Written reviews point the same way: 0% of Compression Calculator's written reviews are positive against 78% of PowerVision 4's.

Compression Calculator ships an update every 9 days, PowerVision 4 monthly. The most recent releases landed on September 30, 2026 and October 19, 2026 respectively.

## The numbers

| Metric | Compression Calculator | PowerVision 4 |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.0 (3 ratings)](https://appshunter.io/ios/app/compression-calculator/id1421927149/reviews) | **[4.9 (312 ratings)](https://appshunter.io/ios/app/powervision-4/id1559102553/reviews)** |
| Number of ratings | 3 | **312** |
| Positive reviews | 0.0% of reviews | **77.9% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 9 days** | Monthly |
| Monetization | **Free** | Free with in-app purchases |
| Size | 10 MB | 104 MB |
| Requires iOS | **11.4** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Peter Linszter](https://appshunter.io/developer/530077583) | [Dynojet](https://appshunter.io/developer/686107623) |

## What reviewers say

### Compression Calculator

[App page](https://appshunter.io/ios/app/compression-calculator/id1421927149)

Calculate engine compression, displacement, and piston speed using specific Honda engine parameters. Select engine components to get precise calculations for your automotive needs.

**Highlights:** Engine compression calculation, Displacement calculation, Piston speed calculation, Honda B, D, H/F, K-Series engine support, Component selection for custom calculations

**Features:** macOS Compatibility

**In-app purchases:** none


### PowerVision 4

[App page](https://appshunter.io/ios/app/powervision-4/id1559102553)

Control your motorcycle's engine performance directly from your iPhone. Access hundreds of pre-loaded engine tunes or create custom ones. Easily flash tunes to your bike's ECU, monitor real-time engine data, and manage diagnostic trouble codes.

**Highlights:** Flash tunes to ECU, Access vast tune database, Record real-time engine data, Read/clear diagnostic codes, Remote tuning optimization, Autotune modes, Active tests for diagnostics

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (8)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Universal Token | $10.00 | one-time |
| Universal Token (3x) | $30.00 | one-time |
| Universal Token (5x) | $50.00 | one-time |
| Universal Token (10x) | $100.00 | one-time |
| Universal Token (15x) | $150.00 | one-time |
| Universal Token (20x) | $200.00 | one-time |
| Universal Token (25x) | $250.00 | one-time |
| Universal Token (30x) | $300.00 | one-time |

**What reviewers like**

- 🚀 Easy to use
- 👍 Intuitive app interface
- 🚀 Fast tuning process
- 👍 Excellent customer support
- 🚀 Responsive bike performance

**What reviewers complain about**

- 🐛 App crashes and connectivity issues
- 🔍 Limited tune options
- 🔍 Lacking advanced tuning features
- 🐛 Inaccurate sensor readings
- 🔍 Clunky gauge operation

**Reported bugs**

- App crashes when using diagnostic functions
- Bluetooth disconnects during tuning process
- Sensor readings not updating correctly
- Tune flashing fails intermittently

**Requested features**

- Add more pre-loaded tune options
- Implement an auto-tune feature
- Improve data logging and cloud integration
- Expand support for wider range of bikes
- Enhance live sensor data display


## Frequently asked questions

### Is Compression Calculator free?

Compression Calculator is free to download, with no in-app purchases.

### Is PowerVision 4 free?

PowerVision 4 is free to download, with in-app purchases available.

### Which has better reviews, Compression Calculator or PowerVision 4?

PowerVision 4 is rated higher. Compression Calculator averages 3.0 out of 5 from 3 ratings, while PowerVision 4 averages 4.9 from 312 ratings.

### Do Compression Calculator or PowerVision 4 have ads?

Neither Compression Calculator nor PowerVision 4 shows ads.

### Which is updated more often, Compression Calculator or PowerVision 4?

Compression Calculator ships an update every 9 days, and PowerVision 4 monthly. Most recently, Compression Calculator was updated on September 30, 2026 and PowerVision 4 on October 19, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*