# 三元催化风向标 vs 修车助手HD

The clearest difference is in-app purchases: 修车助手HD at none against 三元催化风向标's 10. 修车助手HD also leads on update cadence (every 3 weeks vs every 2 months). 三元催化风向标's advantage is iOS requirement (13.0 vs 15.5). On price, ads and device support there is nothing between them.

Both are free to download. 三元催化风向标 sells 10 one-off in-app purchases. 修车助手HD asks for nothing beyond the download.

三元催化风向标 ships an update every 2 months, 修车助手HD every 3 weeks. The most recent releases landed on September 8, 2026 and September 17, 2026 respectively.

## The numbers

| Metric | 三元催化风向标 | 修车助手HD |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/hd/id6602885548/reviews)** |
| Number of ratings | — | **1** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | Yes | Yes |
| Update frequency | Every 2 months | **Every 3 weeks** |
| Monetization | — | Ad-supported |
| Size | 35 MB | 108 MB |
| Requires iOS | **13.0** | 15.5 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 17+ |
| Developer | [Shenzhen Youyu Technology Co., Ltd.](https://appshunter.io/developer/1190014252) | [Tongling Diyi Information Technology Development Co., Ltd](https://appshunter.io/developer/1721086091) |

## What reviewers say

### 三元催化风向标

[App page](https://appshunter.io/ios/app/id1542725614)

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

**In-app purchases (10)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Plus体验卡1天 | $3.99 | one-time |
| 初级 66次(3个月) | $19.99 | one-time |
| 初级 300次(1年) | $59.99 | one-time |
| 团队版(1个月) | $69.99 | one-time |
| 专业版Plus（2个月） | $99.99 | one-time |
| 团队版(2个月) | $129.99 | one-time |
| 专业版Plus（半年） | $249.99 | one-time |
| 团队版(半年) | $349.99 | one-time |
| 专业版Plus（1年） | $499.99 | one-time |
| 团队版（一年） | $599.99 | one-time |


### 修车助手HD

[App page](https://appshunter.io/ios/app/hd/id6602885548)

This utility app provides helpful resources for car maintenance and repair. It is updated weekly and offers a community forum for members to ask questions and get assistance from customer service if specific information cannot be found.

**Highlights:** Weekly updates, Member community forum, Customer support for missing data, Car maintenance resources

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

**In-app purchases:** none


## Frequently asked questions

### Is 三元催化风向标 free?

三元催化风向标 is free to download, with in-app purchases available.

### Is 修车助手HD free?

修车助手HD is free to download, with no in-app purchases.

### Do 三元催化风向标 or 修车助手HD have ads?

Both 三元催化风向标 and 修车助手HD show ads.

### Which is updated more often, 三元催化风向标 or 修车助手HD?

三元催化风向标 ships an update every 2 months, and 修车助手HD every 3 weeks. Most recently, 三元催化风向标 was updated on September 8, 2026 and 修车助手HD on September 17, 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.*