Fuel vs simos.app
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Fuel
Monitor your vehicle's ethanol concentration and fuel temperature in real-time. This app wirelessly connects to a compatible Bluetooth module, freeing up your device's port for simultaneous charging and monitoring. It includes an ethanol fill-up concentration calculator and customizable display views.
- Real-time ethanol concentration monitoring
- Real-time fuel temperature monitoring
- Wireless Bluetooth connectivity
- Ethanol fill-up concentration calculator
- Fahrenheit or Celsius display options
- Two display views
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***Note that this app requires a custom Bluetooth module to function. Info on the module can be found here: https://fuel-it.com/products/fuel-it-bluetooth-flex-fuel-analyzer The Fuel-It ECA gives you realtime feedback from your Continental Ethanol sensor. Wireless communication frees up your device's port so you can monitor and charge at the same time. Features: Ethanol concentration monitoring Fuel temperature monitoring 2 Display Views Fuel temperature display in Fahrenheit or Celsius Ethanol fill-up concentration calculator
simos.app
This tool provides diagnostic, data logging, and flashing capabilities for VAG petrol engines with specific Simos ECUs. Monitor real-time engine parameters, analyze recorded sessions with graphs, and update your ECU with stock or custom tunes.
- Real-time ECU parameter monitoring
- Live data logging via Bluetooth LE
- ECU identification (software/calibration IDs)
- Multi-channel graph analysis of logged sessions
- ECU and TCU flashing (stock and custom tunes)
- Support for Simos 18.x and 12.1 ECUs
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simos.app is a diagnostic, data logging and flashing tool built specifically for VAG petrol engines running Simos 18.1, 18.2, 18.6, 18.10 and Simos 12.1 ECUs. The platforms found in most modern TSI and TFSI engines across Audi, VW, Škoda, SEAT, Cupra and Porsche. LIVE DATA LOGGING Read ECU parameters directly in real time. Monitor boost pressure, injection timing, lambda, temperatures, torque and more at high sample rates over a Bluetooth LE connection. ECU IDENTIFICATION Read software versions, calibration IDs and hardware info straight from the control unit. LOG ANALYSIS Visualize recorded sessions with multi-channel graphs. Spot correlations between parameters without leaving the app. FLASHING Update your ECU and TCU to the latest version for your vehicle or flash a custom tune. Full features available for Simos 18.1/18.10 and 18.6. Flashing stock files or pre-unlocked ecus for Simos 18.2, 18.4, 18.41 and Simos 12.1. –– Built for enthusiasts, tuners and workshops who need more than a generic scan tool. Basic knowledge of ECU diagnostics is recommended. This app is for informational and diagnostic purposes only. Any modifications to vehicle systems are the sole responsibility of the user and must comply with local laws and regulations. –– Bluetooth LE OBD adapter required. Get yours here: https://simos.app/dongle Other compatible adapters: Macchina A0, DIY A0 clone https://github.com/Switchleg1/AMAleg require custom firmware: https://simos.app/dongle/firmware
Screenshots
Verdict
The clearest difference is rating: simos.app at 5.0 against Fuel's 3.1. simos.app also leads on update cadence (every 4 days vs every 10 months). Fuel's advantage is ratings volume (33 vs 2) and iOS requirement (13.4 vs 17.6). On price, ads, in-app purchases and monetization model there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
simos.app holds the better App Store score, 5.0 against 3.1. That said, the two scores are not equally well evidenced: Fuel has 33 ratings behind it against 2, so its average is the more settled of the two.
Fuel ships an update every 10 months, simos.app every 4 days. The most recent releases landed on October 6, 2026 and October 1, 2026 respectively.
| Parameter | Fuel | simos.app |
|---|---|---|
| Price | Free | Free |
| Rating | 3.1 (33 ratings) | 5.0 (2 ratings) — better |
| Positive reviews | 50.0% of reviews | — |
| Number of ratings | 33 — better | 2 |
| Update frequency | Every 10 months | Every 4 days — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPod — better | iPhone |
| Requires iOS | 13.4 — better | 17.6 |
| Further details — not scored | ||
| Size | 20 MB | 6 MB |
| Age rating | 4+ | 4+ |
| Developer | Dmac Mobile Developments, LLC | Tycho Sebastian Holzer |
Customer experience
Fuel
simos.app
In-app purchases
Fuel
No in-app purchases
simos.app
No in-app purchases









