Electronic ignition and fuel injection for the 0-200

[Tom Downey]

any one have experience with this system?
http://www.sdsefi.com/aircraft.html

I seems to me that you could eliminate the requirement for carb hot air, and the mixture control with this system,, true or ?

[1600vw]

It's my understanding with fuel injection one does not have carb heat. Also not all airplanes with carbs make ice or need carb heat. The airplane I fly has a carb. It does not make ice. Its in how it was built. Has to do with the cowling of the engine. I was concerned about this so I installed a carb heat gauge. What I found using this gauge. The carb gets warm as the engine warms or gets hot. It also does not draw air from outside the cowl. All air that goes into the carb is sucked from inside the cowl. Could I be loosing a few hp do to warm air being introduced into the engine? Maybe. But I like it this way. I never have to worry about carb ice. But I still think about it and listen for it. I have never heard anything that would suggest it was building as I was flying.

My point. Most airplanes using a carb build ice, some do not. Injected engines do not even have a carb heat lever for they do not use carb heat. I have no idea about mixture control. I would think an Injected engine would still offer or have this. But I have no idea. Someone else may offer insight into this.

Tony

[Mike M]

any one have experience with this system?
http://www.sdsefi.com/aircraft.html

I do not. This guy does : http://registry.faa.gov/aircraftinqu...umbertxt=521XD

and these guys do: http://registry.faa.gov/aircraftinqu...mbertxt=N764JM

I seems to me that you could eliminate the requirement for carb hot air, and the mixture control with this system,, true or ?

True.

[DanH]

any one have experience with this system?
http://www.sdsefi.com/aircraft.html

Ross Farnham, good guy, knows his stuff. His systems have been around a long time.

[Bob Dingley]

any one have experience with this system?
http://www.sdsefi.com/aircraft.html

I seems to me that you could eliminate the requirement for carb hot air, and the mixture control with this system,, true or ?

It seems that you could.
However, you would have an electrically dependent engine. The pictures show a real slick dual parallel fuel pump. I was not able to dig out what the power requirements are for this or how much the power the control gear uses. SDS says in the paragraph "Disadvantages of SDS vs Conventional AirCraft systems" that some users are installing either a standby altenator or battery or both.
I checked out the web site a European engine set up the same as this. Simple FADEC and dual parallel fuel pump and they had this info: 30 Amp built in alt. Load for single pump and FADEC together = 15 Amp. They ran an engine in the test cell with a 20AH battery. Something other than a lead acid. They "killed" the Alt and got about an hour of run time before it quit.
Lets see, an O-200 has a pad for a vacume pump. A small standby alt would fit there. I would not take this engine across west Texas until it could go a couple of hours after losing an altenator. Just my thots.

[skyfixer8]

Tony, While fuel injected engines do not have a carb ice control, they do have an alternate air control which is either automatic or lever controlled. Sucks in air from inside cowling to get rid of induction icing.

[Greg Wilson]

Tony, While fuel injected engines do not have a carb ice control, they do have an alternate air control which is either automatic or lever controlled. Sucks in air from inside cowling to get rid of induction icing.

With conventional GA fuel injection systems the alternate air is protection against air inlet blockage. This most often is airframe ice that covers the air filter but would include anything that blocks the normal air inlet. The spring-loaded alternate door will be sucked in by intake vacuum or they may be opened manually. The fuel injection systems used by Lyc. and Cont. have the discharge nozzles at the back side of the intake valves there is no fuel vaporization(causing temperature drop), at the throttle body and so no ice at the throttle plate as with a carburetor.

[turtle]

any one have experience with this system?
http://www.sdsefi.com/aircraft.html

I know at least ten people with SDS systems. All of them say it's the greatest thing since sliced bread. None of them actually have it installed and most ended up going with a tried and true carb, but they know SDS is way better.

The benefits of automatic mixture adjusting and fuel trim does not make up for the extra complexity. Every test I've done has proven electronic ignition is no better than a mag for power, fuel savings or reliability. EFI could give fuel savings, but the extra hardware for redundancy adds weight. The extra cost would never be recovered. Not to mention, one failure and you are AOG until SDS sends you the exact replacement parts.

[Mike M]

...every test I've done has proven electronic ignition is no better than a mag for power, fuel savings or reliability. EFI could give fuel savings, but the extra hardware for redundancy adds weight.

I've done no tests on EFI systems. Empirical evidence only with one electronic ignition, one aircraft, two engines. The spark advance is variable, not fixed like a magneto. One electronic replaced one mag on O320 Lycomings. Extra weight and complexity for redundancy zero, because I left one mag on. Fuel burn in cruise flight 1/2 gallon per hour less than before. Same pilot, same techniques, same altitudes and operating conditions. Since installation on first engine, have had one mag fail and replaced second mag for high time when changed the engine. Same electronic ignition went onto fresh engine. No recurrent maintenance required in 14yrs except replacing flex hose to vacuum advance sensor, oh, yeah, spark plugs, they come in four packs from TSC. Your mileage may vary, because this was not a test.

[DanH]

There is an argument for EFI specific to the O-200 or an O-320, both of which tend to have rather poor mixture distribution. The SDS system now includes on-the-fly electronic injector trim, so assuming the aircraft has accurate EGT instrumentation, it is possible to do the equivalent of a GAMI injector balance, in minutes, at no cost.

Point is, either EFI or a conventional constant flow fuel injection offer improvement when replacing a carburetor, as described by Mike above. Real improvement requires injector balance. The SDS is easier to balance. In return, yes, it is more complex, it is electrically dependent, etc.