# SDG Rotor vs SP Grid Viewer

The clearest difference is update cadence: SDG Rotor at every 2 days against SP Grid Viewer's every 4 months. On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

SDG Rotor ships an update every 2 days, SP Grid Viewer every 4 months. The most recent releases landed on October 23, 2026 and October 5, 2026 respectively.

## The numbers

| Metric | SDG Rotor | SP Grid Viewer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/sdg-rotor/id6480425498/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 2 days** | Every 4 months |
| Monetization | Free | — |
| Size | 46 MB | 83 MB |
| Requires iOS | 15.6 | 15.6 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | +17 | 4+ |
| Developer | [Stephan Monette](https://appshunter.io/developer/1299469285) | [Stage Precision GmbH](https://appshunter.io/developer/1852817409) |

## What reviewers say

### SDG Rotor

[App page](https://appshunter.io/ios/app/sdg-rotor/id6480425498)

This tool helps high-performance vehicle owners ensure the safety of their supercharger rotor RPM. It allows users to input supercharger details and engine RPM for instant safety checks, leveraging expert knowledge in performance vehicles.

**Highlights:** Supercharger rotor RPM safety checks, Input supercharger details and engine RPM, Instant safety assessments, Expertise in high-performance vehicles, User-friendly design, Supports global units and standards

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

**In-app purchases:** none


### SP Grid Viewer

[App page](https://appshunter.io/ios/app/sp-grid-viewer/id6741116815)

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

**In-app purchases:** none


## Frequently asked questions

### Is SDG Rotor free?

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

### Is SP Grid Viewer free?

SP Grid Viewer is free to download, with no in-app purchases.

### Do SDG Rotor or SP Grid Viewer have ads?

Neither SDG Rotor nor SP Grid Viewer shows ads.

### Which is updated more often, SDG Rotor or SP Grid Viewer?

SDG Rotor ships an update every 2 days, and SP Grid Viewer every 4 months. Most recently, SDG Rotor was updated on October 23, 2026 and SP Grid Viewer on October 5, 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.*