# JB4 Mobile vs FastR

The clearest difference is price: FastR at Free against JB4 Mobile's $27.99. FastR also leads on rating (4.4 vs 3.8). JB4 Mobile's advantage is in-app purchases (none vs 2) and review sentiment (52% vs 38%). On ratings volume, update cadence, ads and device support there is nothing between them.

FastR is free to download; JB4 Mobile costs $27.99 up front. FastR sells 2 one-off in-app purchases. JB4 Mobile asks for nothing beyond the download.

FastR holds the better App Store score, 4.4 against 3.8. Both are backed by a comparable volume of ratings — 239 and 290 respectively. Written reviews complicate that: 52% of JB4 Mobile's written reviews are positive against 38% of FastR's, so the app with the better star average is not the one people write more warmly about.

JB4 Mobile ships an update every 3 months, FastR every 5 months. The most recent releases landed on September 23, 2026 and September 18, 2026 respectively.

## The numbers

| Metric | JB4 Mobile | FastR |
| --- | --- | --- |
| Price | $27.99 | **Free** |
| Rating | [3.8 (239 ratings)](https://appshunter.io/ios/app/jb4-mobile/id794841332/reviews) | **[4.4 (290 ratings)](https://appshunter.io/ios/app/fastr-0-60-acceleration-test/id1296375567/reviews)** |
| Number of ratings | 239 | **290** |
| Positive reviews | **52.4% of reviews** | 37.5% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 3 months** | Every 5 months |
| Monetization | **Free** | Free with in-app purchases |
| Best chart rank | **#2** | — |
| Size | 24 MB | 20 MB |
| Requires iOS | 15.1 | **15.0** |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Dmac Mobile Developments, LLC](https://appshunter.io/developer/372235786) | [Erhies Fekarurhobo](https://appshunter.io/developer/1296375566) |

## What reviewers say

### JB4 Mobile

[App page](https://appshunter.io/ios/app/jb4-mobile/id794841332)

**Currently charting:** #2 Top Paid · Sports (US App Store)

This app acts as a mobile data logger and display for vehicles equipped with a JB4 tuner. It allows users to monitor and log various engine parameters, view data in real-time, and adjust settings for performance tuning.

**Highlights:** Live gauge monitoring, Data logging and graphing, User adjustable settings, WMI settings modification, On-the-fly map switching, Code reading and deletion

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

**In-app purchases:** none

**What reviewers like**

- 🚀 Great app and a must have with the JB4
- 🔒 Robust security features
- 👍 Awesome data logging
- 👍 Incredible Support
- 👍 Works as expected

**What reviewers complain about**

- 🐛 Doesn't work properly, screen upside down and backwards
- 🐛 Stopped working after update
- 🐛 Bluetooth connection issues
- 🐛 Gauges freezing
- 🐛 Screen turns off

**Reported bugs**

- App crashes
- Can't connect to server
- Mirrored/inverted display
- Compatibility issues with new iOS versions
- Trouble logging in

**Requested features**

- Add CarPlay support
- Allow customizing map names
- Add more gauge styling options
- Improve UI and layout
- Integrate with Apple Carplay


### FastR

[App page](https://appshunter.io/ios/app/fastr-0-60-acceleration-test/id1296375567)

Measure your vehicle's acceleration performance with this app. It automatically tests 0-60 and quarter-mile times with millisecond accuracy. Compete with others on a real-time leaderboard and save results for different car models.

**Highlights:** Hands-free, automated acceleration testing, 0-60 and Quarter mile time measurement, Millisecond accuracy, Real-time user ranking, Save times for different car models

**Features:** macOS Compatibility

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 10 Leaderboard Posts | $3.99 | one-time |
| Unlock 1/4 Mile Timing | $5.99 | one-time |

**What reviewers like**

- 👍 Easy to use interface and simple design
- 💡 Innovative concept for testing 0-60 times without expensive equipment
- 🏆 Competitive leaderboard feature for sharing times
- 📱 Well-designed app layout
- ✅ Accurate readings for slower vehicles (6+ second 0-60 times)

**What reviewers complain about**

- 🐛 Severe GPS lag and timing delays (1-3+ seconds behind actual speed)
- ❌ Highly inaccurate for high-performance vehicles (sub-5 second 0-60)
- 🔌 Network connection issues preventing app functionality
- 📵 Login and authentication problems (Facebook-only requirement)
- ⚠️ Inconsistent and unreliable acceleration measurements

**Reported bugs**

- Network connection errors preventing vehicle selection
- Facebook login buffering and not connecting
- App fails to record and save acceleration times
- GPS speed readings lag significantly behind actual speed
- App crashes on launch or during use

**Requested features**

- GPS-based auto-start feature instead of manual start button
- Audio cues for 'ready, set, go' countdown
- Alternative login methods beyond Facebook
- Save vehicle selection for future sessions
- Support for multiple vehicles per account


## Frequently asked questions

### Is JB4 Mobile free?

JB4 Mobile costs $27.99, with no in-app purchases.

### Is FastR free?

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

### Which has better reviews, JB4 Mobile or FastR?

FastR is rated higher. JB4 Mobile averages 3.8 out of 5 from 239 ratings, while FastR averages 4.4 from 290 ratings.

### Do JB4 Mobile or FastR have ads?

Neither JB4 Mobile nor FastR shows ads.

### Which is updated more often, JB4 Mobile or FastR?

JB4 Mobile ships an update every 3 months, and FastR every 5 months. Most recently, JB4 Mobile was updated on September 23, 2026 and FastR on September 18, 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.*