Engine Monitor Units & GPS-Coupled Fuel Totalisers
The Essential Investment for Elevated Aircraft Operation and Situational Awareness: Avoiding Incidents and Enhancing Safety.
We firmly believe that certain essential equipment can significantly improve aircraft operation and situational awareness. Every aircraft should be equipped with engine monitor units (EMUs) and GPS-coupled fuel totalisers. Additionally, when necessary for lean-of-peak (LOP) operation, tuned fuel injectors are invaluable and full-flow oil filters should be standard. We’ll delve into the specifics of tuned fuel injectors and full-flow oil filters in a future discussion. Today, our focus is on engine monitor units and GPS-coupled fuel totalisers.
Benefits of Engine Monitor Units & GPS-Coupled Fuel Totalisers
EMUs offer critical insights that enhance the operation of your aircraft. They not only allow in-flight observation of temperatures and essential engine parameters but also aid in engine condition monitoring and troubleshooting on the ground. Many legacy aircraft are often minimally instrumented. Typically, they might only feature a single cylinder-head-temperature (CHT) and an exhaust-gas-temperature (EGT) probe. However, relying on readings from just one cylinder can be misleading, even if the probes are situated on what appears to be the hottest cylinder. To truly understand and competently operate an aircraft engine for heightened efficiency, performance, reliability, and longevity, it’s pivotal to have an engine fully instrumented. At a minimum, the EMU should display and record EGT and CHT for each cylinder, as well as manifold pressure (MAP), propeller speed (RPM), fuel flow, and outside-air-temperature (OAT) for each engine installed on the aircraft.
Data from the EMU is crucial. It enables early detection of potential issues, preventing catastrophic outcomes like exhaust valve failures. Furthermore, it’s indispensable when trying to identify and troubleshoot elusive problems.
GPS-coupled fuel totalisers significantly boost situational awareness. They deliver real-time updates about fuel flow, remaining fuel, consumed fuel, endurance, and fuel reserves.
Any advanced aviator would consider these tools indispensable. Both EMUs and GPS-coupled fuel totalisers ought to be top on the list of enhancements for any aircraft.
Manufacturers & Models
We have carefully identified and listed the most valuable options for both engine monitor units and GPS-coupled fuel totalisers. Most of the EMUs mentioned below include fuel totaliser functions, making them our preferred options. In total, we reviewed five different manufacturers: three that provide equipment for Continental and Lycoming engines, one supporting the Rotax 9xxiS engines, and one that accommodates both.
We did not include notable products from Dynon, Advanced Flight Systems, Vertical Power, etc. This exclusion is not a reflection on the quality of their products. These manufacturers produce top-notch items and might be featured in a dedicated blog post in the future but have not been considered for this list.
We have compiled a matrix that includes the most relevant models from each manufacturer, allowing for a comparison of various features and characteristics. The columns listed were chosen for easier feature and characteristic comparisons. Given the abundance of options and configurations offered by different manufacturers, it’s challenging to make a universally applicable statement. The values provided should be seen as indicative rather than absolute, both for features and costs.
| Manufacturer | Model | Operating Mode(s) | Compatible Engine(s) | Certification | Installation | Sample Rate | Data Interface | Price |
|---|---|---|---|---|---|---|---|---|
| Electronics International Inc. | CGR-30P Basic Engine Monitor | EMU + GPS-coupled fuel totaliser | Continental and Lycoming | FAA, TCCA, and EASA | - Mounts in a standard 3.125″ instrument hole (round flush installation) | Three samples per second | USB port (remote) | 4-Cylinder: $3,798 6-Cylinder: $4,598 |
| Electronics International Inc. | CGR-30P Premium Engine Monitor | EMU + GPS-coupled fuel totaliser | Continental and Lycoming | FAA, TCCA, and EASA | - Mounts in a standard 3.125″ instrument hole (round flush installation) | Three samples per second | USB port (remote) | 4-Cylinder: $4,598 6-Cylinder: $4,998 Twin 4-Cylinder: $8,998 Twin 6-Cylinder: $9,998 |
| Electronics International Inc. | MVP-50P Engine Monitor | EMU + GPS-coupled fuel totaliser | Continental and Lycoming | FAA | - Rectangular cutout (mounts flush with the panel) | Three samples per second | USB port (panel) | Certified/Experimental 4-Cylinder: $7,000/$6,000 6-Cylinder: $7,500/$6,500 Twin 4-Cylinder: $14,600/ - - - Twin 6-Cylinder: $15,600/ - - - |
| Electronics International Inc. | FP-5L Fuel Computer | GPS-coupled fuel totaliser | Continental, Lycoming, and Rotax | FAA | - Mounts in a standard 2.25″ instrument hole (round flush installation) | - - - | - - - | $496 - $1,296 |
| Garmin Ltd. | GI275 Engine Indication System (EIS) | EMU + GPS-coupled fuel totaliser | Continental and Lycoming | FAA and EASA | - Mounts in a standard 3.125″ instrument hole (round flush installation) | One sample per second | Wireless flight data logging via Connext & GSB™ 15 charging hub | Starting at $5,035 |
| Garmin Ltd. | TXi Engine Indication System (EIS) - Dedicated 7" EIS Display | EMU + GPS-coupled fuel totaliser | Continental and Lycoming | FAA and EASA | - Rectangular cutout | One sample per second | Stream to Garmin Pilot when paired with Flight Stream 510 wireless gateway | 4-Cylinder: $9,985 6-Cylinder: $10,347 Twin 4-Cylinder: $15,875 Twin 6-Cylinder: $16,599 |
| Garmin Ltd. | G3X Touch™ for Certified Aircraft - 7” Portrait EIS | EMU + GPS-coupled fuel totaliser | Continental and Lycoming | FAA and EASA | - Rectangular cutout | One sample per second | Wireless flight data logging via Connext & Memory card slot | 4-Cylinder: $8,543 6-Cylinder: $8,905 |
| Garmin Ltd. | G3X Touch™ for Experimental Aircraft - 7” Portrait EIS | EMU + GPS-coupled fuel totaliser | Continental, Lycoming, and Rotax | - - - | - Rectangular cutout | One sample per second | Wireless flight data logging via Connext & Memory card slot | $3,360 + $925 for GEA™ 24 Engine Indication System (EIS) |
| Garmin Ltd. | G3X Touch™ for Experimental Aircraft - 10.6” Portrait EIS | EMU + GPS-coupled fuel totaliser | Continental, Lycoming, and Rotax | - - - | - Rectangular cutout | One sample per second | Wireless flight data logging via Connext & Memory card slot | $4,210 + $925 for GEA™ 24 Engine Indication System (EIS) |
| Insight Avionics | G2 | EMU + fuel totaliser | Continental and Lycoming | FAA and TCCA | - Mounts in a standard 2.25” instrument hole | One sample per second | Memory card slot | 4-Cylinder: $2,093 6-Cylinder: $2,275 |
| Insight Avionics | G3 | EMU + fuel totaliser | Continental and Lycoming | FAA and TCCA | - Mounts in a standard 2.25” instrument hole | One sample per second | Memory card slot | 4-Cylinder: $3,185 6-Cylinder: $3,367 |
| Insight Avionics | G4 Single | EMU + fuel totaliser | Continental and Lycoming | FAA and TCCA | - Mounts in a standard 3.125” instrument hole | One sample per second | Memory card slot | 4-Cylinder: $3,998 6-Cylinder: $4,225 |
| Insight Avionics | G4 Twin | EMU + fuel totaliser | Continental and Lycoming | FAA and TCCA | - Mounts in a standard 3.125” instrument hole | One sample per second | Memory card slot | 4-Cylinder: $5,980 6-Cylinder: $6,305 |
| J.P. Instruments (JPI) | EDM 350 | EMU + GPS-coupled fuel totaliser optional | Continental and Lycoming | - - - | - Mounts in a standard 3.125” instrument hole | One sample per one to 500 seconds | USB port (panel) | Basic Model EDM-350-4C 4 Cylinder EGT/CHT: $798 Basic Model EDM-350-6C 6-Cylinder EGT/CHT: $988 Options (Plug & Play) RPM: $299, MAP: $299, OIL-P: $299, OIL-T: $195, OAT: $195, FUEL-P: $320 STD, FUEL-P: $495 TURBO, TIT: $195, CRB: $195, Fuel Flow: $490, FF Press Carb: $595, CDT: $195, Volts-2: $95, Remote Alarm Light: $92 |
| J.P. Instruments (JPI) | EDM 730 | EMU + GPS-coupled fuel totaliser optional | Continental and Lycoming | - - - | - Mounts in a standard 3.125” instrument hole (flush mount option available) | One sample per two to 500 seconds | USB port (panel) | Basic Model EDM-730-4C 4-Cylinder: $2,023 Basic Model EDM-730-6C 6-Cylinder: $2,844 Options Fuel Flow Option w/ Transducer: $539, Engine RPM Option w/ Non-Pressurised Mag: $299, OAT: $195, Oil Temp: $195, Oil Pressure w/harness: $299, MAP: $299, TIT: $195, IAT: $195, CRB: $195, Flush Mount: $85 |
| J.P. Instruments (JPI) | EDM 790 LCD Twin | EMU + GPS-coupled fuel totaliser optional | Continental and Lycoming | FAA | - Mounts in a standard 3.125” instrument hole | One sample per two to 500 seconds | USB port (panel) | EDM-790-4C 4-Cylinder: $4,920 EDM-790-6C 6-Cylinder: $6,360 Options Fuel Flow w/o Transducers: $995, Fuel Flow w/ 2 Transducers: $1,380, Oil Temp: $390, TIT: $390, OAT: $195, CDT: $390, IAT: $390 |
| J.P. Instruments (JPI) | EDM 830 | EMU + GPS-coupled fuel totaliser | Continental and Lycoming | - - - | - Mounts in a standard 3.125” instrument hole (flush mount option available) | One sample per two to 500 seconds | USB port (panel) | EDM-830-4C 4-Cylinder with fuel flow and a full GPS interface: $3,364 EDM-830-6C 6-Cylinder with fuel flow and a full GPS interface: $3,691 Options TIT: $195, IAT: $195 CRB: $195, Flush Mount: $94 |
| J.P. Instruments (JPI) | EDM 900 Primary | EMU + GPS-coupled fuel totaliser | Continental and Lycoming | FAA and EASA | - Mounts in a standard 3.125” instrument hole (flush mount option available) | One sample per one to 500 seconds | USB port (panel) | 4-Cylinder Primary Kit L/R 2 Fuel Tanks , With FloScan Transducer: $6,359 6-Cylinder Primary Kit L/R 2 Fuel Tanks , With FloScan Transducer: $6,913 Additional options available. |
| J.P. Instruments (JPI) | EDM 930 Primary/ Experimental | EMU + GPS-coupled fuel totaliser | Continental and Lycoming | FAA and EASA | - Rectangular cutout (mounts flush with the panel) | One sample per two to 500 seconds | USB port (panel) | 4-Cylinder Primary Kit L/R 2 Fuel Tanks , With FloScan Transducer: $7,904 6-Cylinder Primary Kit L/R 2 Fuel Tanks , With FloScan Transducer: $8,280 Additional options available. |
| J.P. Instruments (JPI) | EDM 960 Twin | EMU + GPS-coupled fuel totaliser | Continental and Lycoming | FAA and EASA | - Rectangular cutout (mounts flush with the panel) | One sample per two to 500 seconds | USB port (panel) | 4-Cylinder For L/R 2 Fuel Tanks: $15,214 6-Cylinder For L/R 2 Fuel Tanks$: 16,531 Additional options available. |
| RS/Stock Flight Systems | EMU 9xiS | EMU | Rotax | - - - | - Rectangular cutout | Ten samples per second | Memory card slot | €3,800 |
Top Five Engine Monitor Units & GPS-Coupled Fuel Totalisers
Choosing a device from the list can be challenging, and personal preferences certainly play a role. We’ve pinpointed five devices that we would install in our aircraft, considering factors like functions, engine compatibility, certification, installation ease, and price. All the devices listed offer both EMU and GPS-coupled fuel totaliser functions. The order of the devices listed is alphabetical and does not indicate a ranking.
Device #1: CGR-30P Premium Engine Monitor from Electronics International Inc.
Electronics International Inc. offers the CGR-30P Premium Engine Monitor, designed to fit seamlessly into an existing 3 1/8″ hole in your avionics panel. It holds certifications from the FAA, TCCA, and EASA. This monitor, offered at an attractive price point, comes as a comprehensive package and permits customisation of some engine limits via configuration files—however, only for non-primary functions. Packages for multi-engine aircraft are also available. Data recording is straightforward, with a sample rate of 3 samples per second that can be customised. The data is downloadable through an USB port, which can be conveniently placed, depending on individual installation needs.
The CGR-30P Premium Engine Monitor is designed for aircraft powered by Continental and Lycoming engines. We value its all-inclusive package and the flexibility it offers due to its range of options. Moreover, the addition of a remote annunciator boosts situational awareness.
Device #2: GI275 Engine Indication System (EIS) from Garmin
Garmin‘s GI275 Engine Indication System integrates smoothly into an existing 3 1/8″ hole in your avionics panel and is (at least) FAA and EASA certified. While it carries a premium price, it offers a comprehensive package. Unfortunately, engine limits cannot be customised. Data recording is user-friendly, capturing one sample per second. Data transfer is possible via Connext or the GSB™ 15 charging hub, which can be placed based on the installation’s requirements.
The GI275 Engine Indication System is provided for Continental and Lycoming powered aircraft only but offers a solid value for the investment, particularly for aircraft already equipped with other Garmin devices. The quality of the device and screen is impeccable.
Device #3: EDM 350 from J.P. Instruments (JPI)
Notably, J.P. Instruments (JPI) has secured two spots on our list, starting with the EDM 350. This device fits seamlessly into an existing 3 1/8″ hole in your avionics panel. Designed specifically for experimental aircraft, it is provided as a customisable “kit” and is budget-friendly. Users can almost freely combine engine parameters and probes, and set engine limits as desired. Data recording is intuitive, with a sample rate adjustable from one sample per one to 500 seconds. Users can download the data via a USB port located on the device’s front.
The EDM 350 is an affordable choice for experimental or homebuilt aircraft powered by Continental or Lycoming engines. With its customisable kit format, users can tailor the monitor based on their specific needs and budget. For instance, one can set up an EMU to monitor and record CHT/EGT for each cylinder, MAP, RPM, fuel flow, OAT, and include a panel-mounted remote annunciator, all for as low as $2173.
Device #4: EDM 930 from J.P. Instruments (JPI)
The EDM 930, JPI‘s second entrant, can be either directly mounted into a standard 3 1/8″ hole or flush mounted in your avionics panel. It boasts a generous 6” screen. It holds FAA and EASA certifications, but is also available for experimental aircraft. Offered in various packages with additional options, the EDM 930 carries a premium price tag. Some alarm limits can be customised, but only for non-primary functions. Multi-engine aircraft packages are also available as the EDM 960. Data recording is streamlined, with a sample rate adjustable from one sample per two to 500 seconds. Data can be retrieved via a USB port located on the device’s front.
Specifically designed for Continental and Lycoming powered aircraft, the EDM 930 stands out for its abundance of functions and sizable screen. We appreciate its modular approach, allowing for flexibility in choosing different options. Though it comes with a higher price tag, its countless functions, options, and the impressive screen enhance situational awareness.
Device #5: EMU 9xiS from RS/Stock Flight Systems
RS Flight Systems‘ EMU 9xiS mounts onto the instrument panel through a rectangular cutout. Designed exclusively for experimental aircraft, it offers a comprehensive package at a reasonable price. Some engine limits can be tailored upon request, and the integration of additional sensor inputs is feasible. An exciting feature is the automatic propeller speed control for single lever engine operation when paired with an MT Propeller governor. The device captures georeferenced data recordings of all parameters at ten samples per second. Data can be accessed via an SD card from a slot on the device’s front.
The EMU 9xiS is an ideal pick for Rotax-powered aircraft. We admire its comprehensive package that still provides customisation flexibility. Moreover, the option for single lever engine operation, in combination with MT Propeller governors, is a notable feature.
Device Worth Mentioning: G3X from Garmin
No engine monitor unit list would be comprehensive without the G3X from Garmin. This unit mounts onto the instrument panel using a rectangular cutout and comes in both certified and experimental versions. Paired with GEA 24, the G3X serves as an engine indication system for Continental, Lycoming, and Rotax engines. The experimental version allows for extensive customisation of interfaces and functions. Data recording is straightforward, capturing one sample per second. Data retrieval is facilitated via Connext or an SD card using the slot on the device’s front.
The G3X, combined with GEA 24, is a commendable choice for aircraft powered by Continental, Lycoming, or Rotax engines that are already outfitted with G3X display units. For aircraft equipped or planned to be equipped with the G3X avionics suite, pairing it with the GEA 24 is the go-to choice for a streamlined engine indication system setup.
Conclusion
Navigating the countless options of engine monitor units and GPS-coupled fuel totalisers can be daunting. In our exploration of these devices, we’ve strived to present a comprehensive view of some of the top contenders in the market. As pilots and aircraft enthusiasts, it’s always our goal to find products that provide both top-notch functionality and value.
Restrictive Regulations
One point of contention is the restrictive regulations around customising engine limits, specifically the Cylinder Head Temperature (CHT). While these devices provide countless functions, it’s somewhat disappointing that, when used as primary indications, we can’t customise the limits. Adopting a more conservative approach by setting the CHT well below the manufacturer’s limits is not just a matter of preference. It’s a stand we take for enhanced safety, reliability, and the longevity of our aircraft’s engine. Operating at temperatures consistently closer to the upper limit can expose engines to potential wear and tear, compromising the very essence of what these devices seek to monitor and protect.
Recommendation
Our choice of models was made after rigorous evaluation, taking into account multiple factors ranging from certifications and compatibility to the wide range of features and price points. Each selected model, in our view, stands as a testament to its manufacturer’s commitment to quality and safety in aviation.
For Continental or Lycoming powered certified aircraft, we recommend the CGR-30P Premium Engine Monitor from Electronics International Inc. as the best value-for-money choice. The GI275 Engine Indication System (EIS) from Garmin is another option if you have an affinity for Garmin and/or a slightly larger budget.
If you prefer larger screens, additional features, and have a higher budget, the EDM 930 or EDM 960 (for multi-engine aircraft) from J.P. Instruments (JPI) is the way to go.
For those with Continental or Lycoming engines in experimental homebuilt aircraft, the EDM 350 from J.P. Instruments (JPI) is a top pick in terms of options and price.
Rotax powered aircraft have fewer choices. For experimental aircraft, the EMU 9xiS from RS Flight Systems is a good option. The G3X from Garmin is another option, especially if you can afford it and/or are operating certified aircraft.
The G3X from Garmin fits well for Continental, Lycoming, and Rotax powered aircraft, particularly if already equipped or planning to be equipped with the G3X avionics suite.
Making the Right Choice for Your Needs
We understand that preferences vary, and while we’ve provided our recommendation, we encourage you to explore other EMUs that suit your needs. The manufacturer or model is secondary, it’s essential to have the ability to monitor and record the mentioned parameter at an acceptable sample rate. While having a GPS-coupled fuel totaliser function is beneficial, it remains an optional feature. Choose what best aligns with your requirements.
About Quest Aeronautics
Quest Aeronautics is a state-certified engineering office for aviation, dedicated to shaping the future of general aviation by providing innovative and cost-effective solutions to enhance aircraft performance and operations. With a focus on CS/FAR-23 and experimental/amateur-built (E/A-B) aircraft, Quest Aeronautics provides a range of services including flight testing, aircraft operations and maintenance consulting, high-quality aviation products, and tailored support for E/A-B projects. Collaborating with industry-leading partners, Quest Aeronautics is committed to delivering unparalleled support and expertise to individuals and organisations in the general aviation market.
About Author
Sebastian, the founder of Quest Aeronautics, is a driven and enthusiastic individual with a passion for aviation. Before delving into aviation, he gained valuable experience as a chemical process engineer and laboratory technician. Sebastian holds a Master of Science in Engineering and a commercial pilot licence, with several fixed-wing aircraft ratings under his belt. He has also completed an introduction course for fixed-wing performance and flying qualities flight testing at the National Test Pilot School in Mojave, CA and is compliance verification engineer for flight.