Superior Design= Superior Performance

Phone 403-671-4015

Last update Oct. 12/18

EFI/EI for Lycoming Engines

If you're tired of poor hot starting and rough idle with your mechanical fuel injection system, now there's a better way. Bring your Experimental Lycoming engine into the 21st century with modern electronic controls

We supplied our first Lycoming EFI system for an O-320 back in 1997 and as of 2017, have supplied several hundred ECUs and complete kits for these engines. Collectively, SDS ECUs have accumulated over 550,000 flight hours- more than all other programmable ECUs combined.

Basic components of dual EM-5 4F EFI aviation system for Lycoming 4 cylinder engines. No wiring shown here.

Basic components of single ECU EM-5 6F aircraft EFI system for Lycoming 540. No wiring shown here.

Please be aware that there are numerous variations among Lycoming engines themselves and clones versions as well. Some parts may not fit or may have to be modified in certain cases.


To place your order, it's best to email or phone us to discuss your project as each system is custom made and tailored for each client. We'll get a list of all your details, discuss wiring lengths, colors, options etc. and then quote you. You then pay by Visa or Mastercard, wire transfer or E-transfer for Canadian customers.

Phone 403-671-4015

See SDS Aero CNC'd Components

Please note: our magnet mounting system for Lycoming engines is not compatible with the Sky Dynamics lightweight flywheels or flywheels lacking the 12 tooling holes around the periphery.

Les Kearney's Aero Sport IO-540 with dual SDS EFI EM-5 and SDS Aero billet valve covers

SDS 80mm throttle body on Barrett cold air intake

Crank sensor mount detail

SDS lightweight billet flywheel

Rear coil mount and backup alternator detail

Ashley Miller was kind enough to bring the following to our attention; It seems new Lycoming Thunderbolt engines may come with flywheels which lack the tooling holes to locate our magnet drilling jig. In these cases, you'd have to obtain an older flywheel or get one of our SDS billet ones.

Gaylon Koenning's beautiful RV10 is flying with the dual SDS EFI system in Texas.

Installation photos on Jim Corner's Kitfox

Video on 360 Lycoming running on a Kitfox

Reno 2017

Mark Frederickson took his O-320 powered Lancair to the Medallion Gold win this year using a dual SDS EM-5 system for fuel and spark management. Fantastic accomplishment in his rookie year. Congrats!

Boss for parallel valve Lycoming engines mounts EFI injector in original injector hole. Uses an injector with a stainless steel body for low heat transfer, proprietary high strength- low heat transfer, alloy steel, lower spigot, 7075-T6 retainer ring, stainless cap screws. Threaded adapters have 4 times the tensile and yield strength and many times the fatigue resistance of our competitor's 7075-T6 bodies at 400F. No more welding bosses to induction tubes. Please note, these parts are only sold with complete SDS system orders.

Top mount injector bosses for angle valve Lycoming engines. These have not been tested to fit on aftermarket heads such as ECI at this time. These mounts may require relief of the head in some cases as the Lycoming castings vary somewhat. See photos below in the Dave Anders section here: dave.htm. These parts are only sold with the purchase of a complete SDS kit.

Center mount fuel block for 6 cylinder Lycoming engines

Block mounts through these case bolt holes

Shown with -3 stainless braided lines connected

Dual fuel pump module mounted in an RV10

Super clean installation on Marvin McGraw's IO-390

Detail of baffle mount fuel block on the left side

Very clean ECU and relay box mounting
Marvin's RV flying out of a beautiful strip in TN

Lycoming IO-390 Engines

Be aware that IO-390 engines use a long reach plug and adapter, not the one shown here supplied by one of our competitors. Also note that these engines are timed at only 20 BTDC stock. Please also note that ALL SDS ECUs whether original SDS or rebranded units, must have the actual timing checked with a timing gun to verify accuracy. We've received several reports that the rebranded ones don't have the proper Magnet Position values entered, thus the timing is advanced between 3 and 4 degrees more than indicated on the display. This can lead to high CHTs and possible detonation issues.

Guidance from Lycoming on spark plug reach:
Video of Josh Pepperd doing some STOL river bed flying in Alaska with SDS EFI on his 409 ACE/Lyclone

Josh on a Glacier at 5600 MSL in Alaska. Josh replaced the other brand EFI with SDS and is now much happier.
Video of Bill Beaton's supercharged IO-540 Rocket running SDS EM-5 and CPI

Top mount injector bosses and hard line mockup on IO-540. Stainless steel line is used on the engine, never aluminum. Lines should be supported in 2 places each with Adel clamps off the pushrod tubes.

Bill Beaton's IO-540 on the test stand at Aerosport

Bill's Supercharged Rocket. World's fastest Rocket- 282 mph at Reno 2016

SDS EM-5 in Bill's Supercharged Rocket

540 top coil mount

Fuel block for Lycoming engines mounts to rear baffle sheet metal. Comes with drilling template. Mounts with two AN3 bolts. 1/8NPT outlets and fuel pressure tap on back side. Side entry and exits for fuel in/out 1/4 NPT

Dual Mag cover solution

Lycoming IO-540 Dual System

The 3 photos below show the components of our complete dual Lycoming IO-540. This particular system is destined for a an overseas customer's TIO-540 project.

Main ignition components

Main fuel components, weld-in bosses shown here. Most engines can now be fitted with our screw in bosses

Tefzel wiring harnesses

Dual coil mount for RV10 aircraft. This mounts to the top of the engine mount. Comes with mounting hardware.

Many thanks to Ashley Miller for the design and these photos

Approximate System Weights and Pricing

Four cylinder fuel and spark control, single ECU, twin coil packs, dual pump module, throttle body, injectors, regulator etc.- 15.5 pounds- $4636US

Six cylinder fuel and spark control, single ECU, twin coil packs, dual pump module, throttle body, injectors, regulator etc.- 18 pounds- $5889US

Four cylinder fuel and spark control, dual ECU, twin coil packs, dual pump module, throttle body, injectors, regulator etc.- 17 pounds- $5809US

Six cylinder fuel and spark control, dual ECU, twin coil packs, dual pump module, throttle body, injectors, regulator etc.- 20 pounds- $7098US

Weights above include all wiring and sensors. Does not include spark plugs or plug wires. Weights can vary with harness lengths and coil mount choices. Prices are approximate for parallel valve engines and can vary with options ordered. Angle valve systems are slightly more expensive. Please email us for an exact quote-

A comparison weight for traditional carb, fuel pump and mag parts on a 360 Lycoming is about 17.5 pounds. About 19 if the mag gears are removed.

Optional items:

Individual cylinder fuel trim $300
PC data logging $110
Digital fuel flow output to engine monitor $100 (eliminates Red Cube mechanical flow transducers)

Information We Need When Placing an Order

  • Engine type- size and whether narrow or wide deck
  • Airframe
  • Front case bolt spacing (Lycoming) Either 3.25 or 3.50 inches
  • Fuel block type
  • Coil mounts desired
  • Wiring harness lengths and for us to terminate FF end or not
  • Single or dual ECUs
  • Horizontal or vertical induction (Lycoming)
  • Desired options (fuel trim, fuel flow output, PC data logging)
  • Long or short reach spark plugs (Lycoming angle valve engines)
  • Fuel pump type (finger type or Lear rotary type). This is for cover plate type supplied

    To place your order, it's best to email or phone us to discuss your project as each system is custom made and tailored for each client. We'll get a list of all your details, discuss wiring lengths etc. and then quote you. You then pay by Visa or Mastercard, wire transfer, E-transfer for Candian customers.

    Phone 403-671-4015

    To show our appreciation for the continuing support from our customers, we'll be offering free EM-6 ECU upgrades when they are available later this year to all customers who purchase a complete aviation EM-5 system in 2018. For customers who have purchased a complete aviation kit (EM-5 ECUs only) prior to 2018 (including rebranded EFXX ones), we'll be offering new EM-6 ECUs at a special discounted price. The EM-6 will be the next generation SDS ECU, based on the continuing evolution of EM-1 through EM-5 ECUs going back to 1994. After evaluating new concepts and features over the last year, we'll be starting full scale hardware and software development in late March of this year. We hope to be done testing in the 3rd quarter of 2018 with production release in the 4th quarter of 2018.

    Standard and Optional Features

    SDS offers the following features not found on other vendor kits:

  • Optional individual cylinder fuel trim. Adjust each cylinder's fuel amount +/- 10% to get all cylinders to peak simultaneously.
  • Optional dual ECU access through a single programmer. Flip a switch to toggle between primary and backup ECUs.
  • Standard LOP switch. Configure this to advance or retard the total timing amount and instantly lean mixture per your desires.
  • Optional PC data logging. Log all ECU sensor channels, injector duty cycle to a Windows compatible device for easier tuning.
  • Standard Tefzel wiring harnesses custom built to your length and termination specs.
  • Optional direct fuel flow output. This outputs a pulse train to your glass engine monitor emulating mechanical FloScan transducers, directly from the ECU- no external boxes required.
  • Standard screw-in injector mounts which go into the factory Lycoming injector locations. Robust, proprietary material used unlike competitor's 7075T6 parts. Our bases have 4 times the tensile, yield and fatigue strenth at 350F.

    The new programmers feature a higher temperature spec LCD (-20 to +70C) and adjustable contrast and brightness control. The brightness control was added per customer requests for night flying comfort.

    Here we see the contrast control screen- 16 settings

    This shows the old defaut level brightness

    This is a medium level brightness

    This is a low level setting and the 0 setting is a bit lower than this.

    Rusty Crawford's O-360 powered RV7A in Friendswood, Texas after he applied new paint. Rusty is one of the highest time SDS users with over 1700 hours and has been instrumental in giving us many good ideas and feedback to improve SDS aviation products.

    Tim Collard's O-320 powered Mustang 2. SDS 4D equipped

    Injector installation details.

    Note fire sleeve/ heat shielding to protect fuel line from infrared radiation due to proximity of exhaust pipes.

    08/10/05 update from Tim Collard: "My Mustang 2 has been running on your system now for over 225 hours with no problems [other than my bad wiring]. Getting excellent fuel burns, very even temps, great start up and smooth running. Don't understand why everyone doesn't get an SDS system."

    Joe Block's O-320-E2D powered Glastar is fitted with an SDS EM-4F

    Joe had 470 hours on the installation as of 2007 and reports that he cruises at 30-50F lean of peak and 6.5 GPH at 75%. Operation is very smooth with very close EGTs between cylinders.

    Jim Kidd with his immaculate, award winning IO-540 powered Skybolt. EM-4 6F equipped

    Aerosport 375cid engine with SDS EM-5 EFI/EI

    Running on the test stand. Smooth idle down to 500 rpm.

    Lycoming direct bolt-on 60mm TB with CNC'd 7075T6 throttle arm for vertical or horizontal sumps. Weight 17 ounces with TPS. 2.5 inch snout adapts to airbox with silicone hose. Also shown in photo is IAT sensor adapter to bolt to airbox.

    The 60mm TB is now tapped for a 1/8" vacuum takeoff barb to make MAP and fuel pressure regulator connections easier

    Coil mount bracket for Lycoming 4 cylinder engines, mounts to rear top of crankcase. Fits later wide deck engines only.

    Magneto cover in place

    Hall sensor mount and dual Hall sensor in place

    Weld-in bosses for race applications and engines without the 1/8 NPT injector holes in the heads

    Photos of 3.50 inch bolt spacing Hall mount

    3.25 inch bolt spacing Hall mount. Note mounts have threaded holes to bolt cable protection hardware to.

    Please check the center to center front crankcase bolt distance on four cylinder Lycomings. Some measure 3.25 inches, others 3.50 inches. We need to know this to send you the correct Hall sensor mount.

    Billet 80mm throttle body to replace Bendix RSA-10 and AFP FM-300 servos when converting to EFI. Horizontal mounting.

    Air horn accepts 3.5 inch SCAT hose, 3.5 inch ID K&N filters or 3.5 inch ID Silicone hose couplers. 6061T6 construction, stainless steel shaft riding on sealed roller bearings, 7075T6 throttle arm, brass butterfly, accepts OEM Bosch TPS, O-ring sealed air horn to body and flange to sump. Under 2 pounds and only 3.625 inches high. Integral throttle stop. Stainless hardware.

    Rear coil pack mount for 540 engines

    Spark plugs and adapters for long reach Angle Valve Lycomings (IO-390/ 580)

    MSD Plug Wires and Boots

    Be sure you push the plug and coil boots all the way down to engage the terminals fully. There should be about a 1/8 inch gap as shown in the photo below

    Dave Anders did a very clean SDS EFI installation on his record setting RV4, replacing the mechanical AFP system

    See more info and photos here: dave.htm

    Page on Ralph Inkster's RV6A EM-5 install: projectrv6a.htm

    Magneto Parts to Remove on 6 Cylinder Lycoming Engines

    Exploded view of magneto parts on Lycoming 540 engines: 540magparts.pdf
    When replacing the mags on 6 cylinder Lycoming engines, be sure to remove the gear/ cup (6), cush drive (2) and pilot bearing (7) as shown above. Be very careful not to drop any of the parts into the sump! The extension housing (4) may be removed or left in place as desired

    Aero Sport Power is now an authorized distributor for Racetech/SDS Lycoming products


    Ly-Con Rebuilding Co.

    8231 W. Doe Ave.
    Visalia, CA 93291

    (559) 651-1070
    (559) 651-3212 Fax


    Website: Lycoming EFI