Phone 403-671-4015

Last update Nov. 16/17

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 EFI system for a Lycoming O-320 back in 1997 and as of 2017, have supplied several hundred ECUs and complete kits for these engines

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 aviation EFI system for Lycoming 540. No wiring shown here.

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

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. These parts are only sold with the purchase of a complete SDS kit.

Center mount fuel block. Can be used on 4 and 6 cylinder Lycoming engines

Block mounts through these case bolt holes

Shown with -3 stainless braided lines connected

Super clean installation on Marvin McGraw's IO-390
Marvin's RV flying out of a beautiful strip in TN
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

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- $5186US

Six cylinder fuel and spark control, single ECU, twin coil packs, dual pump module, throttle body, injectors, regulator etc.- 18 pounds- $6289US

Four cylinder fuel and spark control, dual ECU, twin coil packs, dual pump module, throttle body, injectors, regulator etc.- 17 pounds- $6290US

Six cylinder fuel and spark control, dual ECU, twin coil packs, dual pump module, throttle body, injectors, regulator etc.- 20 pounds- $7598US

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-

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)

    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 materials used unlike competitor's 7075T6 parts. Our bases have 4 times the tensile, yield and fatigue strenth at 350F.

    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 1600 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 a 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 IO-540 powered Skybolt. EM-4 6F equipped

    Photo showing kit components for Lycoming O-235/O-320/O-360 and Continental O-200 engines (fuel only). ECU, programmer, dual fuel pumps, fuel pressure regulator, fuel block, vacuum plenum, fiitings, fuel filters, throttle body, injectors, lines and bosses. Not shown is wiring harness. You need fuel return lines to the fuel tanks on aircraft having more than one tank and an Andair Duplex fuel selector.

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

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

    Throttle body, magneto and fuel pump block off plates, automotive spark plug adapaters, single and dual crank sensors, crank sensor mount, CHT and IAT sensor adapters, weld-in injector bosses (side or top feed fuel connections), these can now be replaced by screw-in bosses on most engines having 1/8NPT injector holes in the heads

    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.

    Fuel block for 4 cylinder engines

    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

    Dec. 2015

    Dave Anders is starting a custom, lightweight SDS EFI installation on his record setting RV4, replacing the mechanical AFP system

    Custom machined 65mm throttle body on Sky Dynamics plenum

    Machined down bosses for more clearance and light weight, oval holes in induction tubes

    Fitted before welding

    Bosses welded into intake runners inside bend radius for tight cowling clearance

    Tight squeeze getting the pumps and plumbing in

    Injector mounting detail

    Injector mounting detail

    Fuel block mounted to the firewall

    Neat SDS ECU installation


    Dave has done the first engine start with the EFI and reports much better cold and hot starting over the old AFP system plus an ultra smooth idle down to 650 rpm.


    Dave did his first few test flight over the weekend and is very happy with the initial results. "I have 2500 hrs on my plane and itís never run smoother!!!"


    Clean installation

    Dave reports better takeoff and climb performance and has already been up to 17,500 feet with the system.

    Follow Dave's reports on VAF:


    Dave is now installing the head mount injectors in his engine to do a back to back evaluation against the induction tube mounted ones. He found that there are casting differences in angle valve heads and our bosses would not clear without cutting some reliefs into the heads.

    Super clean installation of lines and wiring

    For Lycoming, Continental, Jabiru and Rotax four cylinder, dual plug engines, we supply these lighter weight coil packs.

    Lycoming Service Instructions on Spark Plugs

    Plug reach specs

    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