# Compression Calculator vs MSD Ultra 6AL

The clearest difference is review sentiment: MSD Ultra 6AL at 100% against Compression Calculator's 0%. MSD Ultra 6AL also leads on rating (5.0 vs 3.0). Compression Calculator's advantage is update cadence (every 9 days vs every 14 months) and ratings volume (3 vs 1). On price, ads, in-app purchases and monetization model there is nothing between them.

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

MSD Ultra 6AL holds the better App Store score, 5.0 against 3.0. Both are backed by a comparable volume of ratings — 3 and 1 respectively. Written reviews point the same way: 0% of Compression Calculator's written reviews are positive against 100% of MSD Ultra 6AL's.

Compression Calculator ships an update every 9 days, MSD Ultra 6AL every 14 months. The most recent releases landed on October 16, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | Compression Calculator | MSD Ultra 6AL |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.0 (3 ratings)](https://appshunter.io/ios/app/compression-calculator/id1421927149/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/msd-ultra-6al/id1604967508/reviews)** |
| Number of ratings | **3** | 1 |
| Positive reviews | 0.0% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 9 days** | Every 14 months |
| Monetization | Free | Free |
| Size | 10 MB | 115 MB |
| Requires iOS | 11.4 | **11.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Peter Linszter](https://appshunter.io/developer/530077583) | [Holley Performance Products](https://appshunter.io/developer/1175069390) |

## 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


### MSD Ultra 6AL

[App page](https://appshunter.io/ios/app/msd-ultra-6al/id1604967508)

This app provides intuitive control and adjustment for ignition systems. Easily manage cylinder configurations, set rev limits, and view real-time parameters. Diagnostic alerts help with troubleshooting.

**Highlights:** Bluetooth connectivity, Cylinder selection, Launch, Burnout & Max Rev Limit settings, Step-Retard programming, Diagnostic alerts, Real-time parameter monitoring

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

**In-app purchases:** none


## Frequently asked questions

### Is Compression Calculator free?

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

### Is MSD Ultra 6AL free?

MSD Ultra 6AL is free to download, with no in-app purchases.

### Which has better reviews, Compression Calculator or MSD Ultra 6AL?

MSD Ultra 6AL is rated higher. Compression Calculator averages 3.0 out of 5 from 3 ratings, while MSD Ultra 6AL averages 5.0 from 1 ratings.

### Do Compression Calculator or MSD Ultra 6AL have ads?

Neither Compression Calculator nor MSD Ultra 6AL shows ads.

### Which is updated more often, Compression Calculator or MSD Ultra 6AL?

Compression Calculator ships an update every 9 days, and MSD Ultra 6AL every 14 months. Most recently, Compression Calculator was updated on October 16, 2026 and MSD Ultra 6AL on October 24, 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.*