# Four vs Engine Lab

The clearest difference is review sentiment: Four at 92% against Engine Lab's 0%. Four also leads on rating (4.7 vs 3.0) and in-app purchases (none vs 1). Engine Lab's advantage is update cadence (every 9 days vs every 7 months). On price, ads and device support there is nothing between them.

Both are free to download. Engine Lab sells 1 one-off in-app purchase. Four asks for nothing beyond the download.

Four holds the better App Store score, 4.7 against 3.0. That said, the two scores are not equally well evidenced: Four has 89 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 92% of Four's written reviews are positive against 0% of Engine Lab's.

Four ships an update every 7 months, Engine Lab every 9 days. The most recent releases landed on October 15, 2026 and October 19, 2026 respectively.

## The numbers

| Metric | Four | Engine Lab |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.7 (89 ratings)](https://appshunter.io/ios/app/four-stroke-otto-engine-3d/id1376010957/reviews)** | [3.0 (1 ratings)](https://appshunter.io/ios/app/engine-lab-simulator-and-sound/id6790748979/reviews) |
| Number of ratings | **89** | 1 |
| Positive reviews | **92.0% of reviews** | 0.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 7 months | **Every 9 days** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 183 MB | 14 MB |
| Requires iOS | **8.0** | 18.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [MOZAIK Education Ltd.](https://appshunter.io/developer/1064850236) | [Jan Sokol](https://appshunter.io/developer/1896490456) |

## What reviewers say

### Four

[App page](https://appshunter.io/ios/app/four-stroke-otto-engine-3d/id1376010957)

Explore the inner workings of a four-stroke Otto engine through interactive 3D animations. This app offers an engaging way to learn about automotive technology with features like rotation, zooming, and predefined views. It's designed for students but enjoyable for all ages, with multilingual support and VR capabilities.

**Highlights:** Interactive 3D engine model, Rotate, zoom, and pan views, Predefined navigation angles, Multilingual support, VR mode compatibility, Built-in animations and narrations

**Features:** macOS Compatibility

**In-app purchases:** none


### Engine Lab

[App page](https://appshunter.io/ios/app/engine-lab-simulator-and-sound/id6790748979)

Explore engine mechanics with a touch-first simulator. Build, tune, and test custom engines, observing animations and hearing synthesized exhaust sounds. Export your creations as WAV files.

**Highlights:** Touch-first engine simulation, Build and save custom engines, Tune engine parameters, Simulated dyno pulls, Crank and piston animation, Native exhaust synthesis, Export WAV audio

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Engine Lab Pro | $4.99 | one-time |


## Frequently asked questions

### Is Four free?

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

### Is Engine Lab free?

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

### Which has better reviews, Four or Engine Lab?

Four is rated higher. Four averages 4.7 out of 5 from 89 ratings, while Engine Lab averages 3.0 from 1 ratings.

### Do Four or Engine Lab have ads?

Neither Four nor Engine Lab shows ads.

### Which is updated more often, Four or Engine Lab?

Four ships an update every 7 months, and Engine Lab every 9 days. Most recently, Four was updated on October 15, 2026 and Engine Lab 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.*