Comparison

Fuel vs simos.app

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

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.

Highlights
  • 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
Features
Read full description

***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

About

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.

Highlights
  • 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
Read full description

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

Fuel3 screens
simos.app4 screens

Verdict

The call

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

CostPrice · In-app purchases · Ads · Monetization

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

ReceptionRating · Positive reviews · Number of ratings

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.

UpkeepUpdate frequency

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.

Scorecard4 real differences · 6 level
Fuel versus simos.app: the parameters behind the verdict, then further details
ParameterFuelsimos.app
PriceFreeFree
Rating3.1 (33 ratings)5.0 (2 ratings) — better
Positive reviews50.0% of reviews—
Number of ratings33 — better2
Update frequencyEvery 10 monthsEvery 4 days — better
AdsNoNo
In-app purchasesNoNo
MonetizationFreeFree
DevicesiPhone, iPod — betteriPhone
Requires iOS13.4 — better17.6
Further details — not scored
Size20 MB6 MB
Age rating4+4+
DeveloperDmac Mobile Developments, LLCTycho Sebastian Holzer

Customer experience

Fuel

All ratings33 ratings
Positive48.5%
Neutral12.1%
Negative39.4%
Written reviews26 reviews
Positive50.0%
Neutral15.4%
Negative34.6%

simos.app

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Fuel

No in-app purchases

None

simos.app

No in-app purchases

Questions

Is Fuel free?
Fuel is free to download, with no in-app purchases.
Is simos.app free?
simos.app is free to download, with no in-app purchases.
Which has better reviews, Fuel or simos.app?
simos.app is rated higher. Fuel averages 3.1 out of 5 from 33 ratings, while simos.app averages 5.0 from 2 ratings.
Do Fuel or simos.app have ads?
Neither Fuel nor simos.app shows ads.
Which is updated more often, Fuel or simos.app?
Fuel ships an update every 10 months, and simos.app every 4 days. Most recently, Fuel was updated on October 6, 2026 and simos.app on October 1, 2026.

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