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  #1  
Old 02-07-2018, 11:33 AM
breister breister is offline
 
Join Date: Dec 2006
Location: Atlanta, GA
Posts: 1,132
Default SDS / EFII Comparison?

I'm confused, perhaps because I'm looking for big differences that aren't there. I've read through both sites (SDS and EFII) and the posts I could find here. It looks like both companies are about to introduce new generation systems which replace both ignition and fuel delivery.

My mission: Cross country and local leisure flying, IFR, no racing.
My objectives: Replace my carburetor and magnetos with a modern integrated system with the expectation of easier starting, better reliability, better power and economy

Can anyone help me with a layman's breakout of differences between the two?
  • First off, are these systems overkill for my objective, and if so what would be the cheaper / less sophisticated integrated solution?
  • Is there a significant difference in system price / installation effort required?
  • Do both systems automatically tune to lean of peak?
  • Are both fully redundant systems suitable for IFR? If so, do both / either require a dual bus battery backup?
  • Anything else a prospective buyer should consider?

Thanks all!
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  #2  
Old 02-07-2018, 04:07 PM
622BH 622BH is offline
 
Join Date: Nov 2011
Location: Albany, OR
Posts: 75
Default EFII

I can't give you a comparison as I have the EFII system and have no experience with SDS.

I went with EFII because a hangar neighbor had one installed in his RV-4 and was quite happy with it - he does aerobatics and has had excellent performance with his system.

Requiring redundancy for IFR work, I have the "legacy" two ECU system installed. Immediately after installation and ground programming, I realized a great improvement in performance of the plane and a reduced fuel usage at altitude.
There are NO hot start issues as there is always cool gas being pushed to the injectors. Thus, starting in the summer is very quick. Winter requires a couple of pumps on the throttle to squirt a bit of fuel into the intake tubes and she fires up right nicely.
I set my idle down to 700 (hot engine) and she runs beautifully.
The legacy system trims all injectors to the same flow - which (on my plane) does not result in equal EGT and best power setting. YES, the system does permit running Lean of Peak (LOP). IF you program the system to run LOP, then that's where it will be when you put the throttle/prop controls at that power setting. OR you can adjust the mixture potentiometer to get the setting you desire.
Both systems do require backup power source(s) as they are fully electron dependent. I went with two batteries and only one alternator (I don't have enough room behind the engine to put one of the B&C units).

I'm eagerly awaiting the new system to start tweaking the settings for each injector to get those EGTs to balance out. Hopefully resulting in an even better fuel savings.

Robert Paisley provides outstanding customer support. Often I would get a response to an email inquiry within minutes of my clicking "send." Can't get any better than that!

Last edited by 622BH : 02-07-2018 at 04:12 PM. Reason: Fully answer the OP's questions.
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  #3  
Old 02-08-2018, 06:47 AM
breister breister is offline
 
Join Date: Dec 2006
Location: Atlanta, GA
Posts: 1,132
Default

Thanks Mel, that's exactly what I was looking for.

Since the fuel system uses a loop invalidating traditional fuel flow sensors, does the system provide a "real" fuel flow output for modern EFIS units to track used / remaining fuel?


Quote:
Originally Posted by 622BH View Post
I can't give you a comparison as I have the EFII system and have no experience with SDS.

I went with EFII because a hangar neighbor had one installed in his RV-4 and was quite happy with it - he does aerobatics and has had excellent performance with his system.

Requiring redundancy for IFR work, I have the "legacy" two ECU system installed. Immediately after installation and ground programming, I realized a great improvement in performance of the plane and a reduced fuel usage at altitude.
There are NO hot start issues as there is always cool gas being pushed to the injectors. Thus, starting in the summer is very quick. Winter requires a couple of pumps on the throttle to squirt a bit of fuel into the intake tubes and she fires up right nicely.
I set my idle down to 700 (hot engine) and she runs beautifully.
The legacy system trims all injectors to the same flow - which (on my plane) does not result in equal EGT and best power setting. YES, the system does permit running Lean of Peak (LOP). IF you program the system to run LOP, then that's where it will be when you put the throttle/prop controls at that power setting. OR you can adjust the mixture potentiometer to get the setting you desire.
Both systems do require backup power source(s) as they are fully electron dependent. I went with two batteries and only one alternator (I don't have enough room behind the engine to put one of the B&C units).

I'm eagerly awaiting the new system to start tweaking the settings for each injector to get those EGTs to balance out. Hopefully resulting in an even better fuel savings.

Robert Paisley provides outstanding customer support. Often I would get a response to an email inquiry within minutes of my clicking "send." Can't get any better than that!
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  #4  
Old 02-08-2018, 07:17 AM
Toobuilder's Avatar
Toobuilder Toobuilder is offline
 
Join Date: Jul 2009
Location: Mojave
Posts: 3,934
Default

WRT the fuel flow, SDS came out with a fuel flow output thats integrated into the ECU a few years ago. That function was not offered on the SDS based EFII systems.

The individual fuel trim function likewise was developed by SDS several years ago and was also not offered to the EFII customers.

And once again, the LOP function has been around a while for SDS users, but once again, EFII stuck with a dumbed down SDS ECU.

Likewise, the individual port mount injectors were an SDS innovation, now several years old, while EFII continued to claim the "superior" performance of the backwards facing, induction tube mounted injectors.

SDS has always offered complete adjustability and tuning of their systems, while EFII has touted that their installations are plug and play - with the settings "tuned by the factory" for your engine.

EFII has now copied all of the SDS innovations and tunability and wrapped it in a ECU with a new color. Yes, the 32 bit box offers some theoretical advantages and certainly growth potential, but thats just hardware... Obviously SDS has a new box in the wings too. The difference is that the SDS box will fly with 25+ years of programming experience behind it and hundreds of thousands of hours operating time.
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WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.

Michael Robinson
______________
Harmon Rocket II -SDS EFI instalation in work
RV-8 - Flying
1940 Taylorcraft BL-65 -flying
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  #5  
Old 02-08-2018, 09:05 AM
622BH 622BH is offline
 
Join Date: Nov 2011
Location: Albany, OR
Posts: 75
Default EFII Fuel Flow

EFII does have fuel flow sensing to feed to an EFIS. The installer will need to tune the settings of the EFIS to gain accurate readings from the system. Re-reading your question, I believe you are speaking of the Open Loop vs Closed Loop Air Fuel Ratio feedback that is current in automobiles. On the EFII system, it is in Open Loop (IIRC), which means the AFR sensor is not feeding data to the ECU to adjust the Air Fuel Mixture in a "live" mode. As I understand the reasoning, that is because of differences in Aviation Fuel compared to unleaded Automotive fuels. EFII or SDS personnel can jump in and speak to that.

With the Air Fuel Ratio input to my AFS-5600T EFIS, I connected it to the "Coolant Temperature" input (at Rob Hickman's recommendation). I asked Rob it that field could be given an "renaming" option so we could re-title it to AFR or such, and he said that would be in a future software update (to date that hasn't happened as it is a low-level request). Configuring the field to read the AFR, I removed any decimal point and read 137 as meaning 13.7 AFR.

So, using the mixture potentiometer, you adjust the mixture to achieve the performance desired at a given power setting (ROP / LOP). Program the ECU for that power setting. From that point forward, the system will run at that setting when you fly with those power settings. But, with that mixture potentiometer, you have the option to fine-tune the mixture +/- 50% at any point in time.

Manifold Pressure readings (constant speed prop) are connected just as you would for non EFII/SDS systems.

In reality, the installation of these systems is not difficult, but the results are very satisfying.

Last edited by 622BH : 02-08-2018 at 09:14 AM. Reason: additional response
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  #6  
Old 02-16-2018, 11:05 PM
stringfellow's Avatar
stringfellow stringfellow is offline
 
Join Date: Mar 2015
Location: Aurora
Posts: 79
Default

Quote:
Originally Posted by 622BH View Post
I went with two batteries and only one alternator (I don't have enough room behind the engine to put one of the B&C units).
Really? Which engine? I am doing the same but hoped that I could drive a B&C off the vac drive.
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  #7  
Old 03-12-2018, 07:43 PM
breister breister is offline
 
Join Date: Dec 2006
Location: Atlanta, GA
Posts: 1,132
Default

Thanks to everyone who responded, I should have closed this out sooner.

I started down this path thinking technology had advanced in the past few years to truly automated / integrated systems. However after both public and private discussions with both users and vendors I came to the conclusion that a) these aren't truly automated, and required at a minimum some period of tinkering to truly determine optimum results across all altitudes, temperatures, power settings, etc.; and b) they aren't truly integrated (i.e. the fuel injection does not truly interact with ignition timing, etc.).

I have no doubt all of these are fine systems; but for my mission (mostly weekend trips) I really couldn't justify $10k or more including installation and tuning costs (I wasn't planning on installing it myself) to get this going in an airplane I only spent $30k on (yes I got a great deal), when at best I might see a few percent better fuel mileage than other cheaper options.

So, at the end of the day I decided to go with replacing one mag with a single popular electronic ignition (as I did in my previous planes) and just keep the carb for now. Using the difference in price I can upgrade to a C/S prop and still have change left over.
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  #8  
Old 03-12-2018, 08:51 PM
rv7charlie rv7charlie is online now
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 2,838
Default

I wouldn't recommend doing anyone's EFI if you're not confident in your own ability to do the mod & tuning, but if you're willing to learn systems, you don't need to spend $10K to get the job done.

http://megasquirt.info/

(Just the most obvious option.)

Charlie
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  #9  
Old 03-13-2018, 03:22 AM
svyolo svyolo is offline
 
Join Date: Oct 2017
Location: bellingham, wa
Posts: 76
Default

I used a Microsquirt on a single cylinder motorcycle successfully. about 8 years ago. Other than somebody who has done wiring for a living, I have probably done more 12v wiring than 99.9% of the population. I would definitely not recommend someone "learn" about fuel injection by cobbing one together on an airplane. Even if I did it, I would consider it only slightly above a "high school science project".

I can scratch build my own EFI system for the airplane I am building, but I would not even consider it as an option. The systems offered on the homebuilt market have a couple of decades of "lessons learned" built into them. Their price, to me, is bargain. A bendix style mechanical FI and 2 pmags costs more than the SDS full system. A new carburetor and 2 new mags costs a bunch as well.

A rebuilt carb and 2 rebuilt mags costs quite a bit less. But you get to rebuild the mags at 500 hours. Every 500 hours. And you will probably rebuild the carb at least once between TBO's. They cost more over time as well than SDS.

EFI on an airplane may not be for everyone yet. You do have to be comfortable wiring something up in a hot/cold/vibrating environment, and have the wiring survive. Or know somebody who can. But properly installed, it is the best, and cheapest option over time.

I know several will argue with me about the cheapest, but when you include fuel savings running LOP (bendix style can do this also), automotive spark plugs vs aircraft (p-mags can use them too), and the fact that the EFI has no moving parts to wear out or that need to be rebuilt (OK a new electric FP every 1000 hours if you like), the EFI pays for itself very quickly. The mechanical Bendix FI and duel EI is a close second. A lot of pilots might be more comfortable with it. I am more comfortable with EFI. But not one I designed myself when my butt is riding in it.

Last edited by svyolo : 03-13-2018 at 03:24 AM.
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  #10  
Old 03-13-2018, 07:03 PM
Bluelabel's Avatar
Bluelabel Bluelabel is offline
 
Join Date: Aug 2013
Location: San Diego, Ca
Posts: 417
Default

Quote:
Originally Posted by Toobuilder View Post
WRT the fuel flow, SDS came out with a fuel flow output thats integrated into the ECU a few years ago. That function was not offered on the SDS based EFII systems.

The individual fuel trim function likewise was developed by SDS several years ago and was also not offered to the EFII customers.

And once again, the LOP function has been around a while for SDS users, but once again, EFII stuck with a dumbed down SDS ECU.

Likewise, the individual port mount injectors were an SDS innovation, now several years old, while EFII continued to claim the "superior" performance of the backwards facing, induction tube mounted injectors.

SDS has always offered complete adjustability and tuning of their systems, while EFII has touted that their installations are plug and play - with the settings "tuned by the factory" for your engine.

EFII has now copied all of the SDS innovations and tunability and wrapped it in a ECU with a new color. Yes, the 32 bit box offers some theoretical advantages and certainly growth potential, but thats just hardware... Obviously SDS has a new box in the wings too. The difference is that the SDS box will fly with 25+ years of programming experience behind it and hundreds of thousands of hours operating time.
this subject has been explored at length here and in other areas.
And on the subject of "new"... The "NEW" SDS thingy will also be untested and therefore require some "beta". Both companies are pushing new boundaries with one, a year ahead of the other in R&D.
As Robert has always said, if you have any questions feel free to email or call them directly. I know he, himself is very rarely on here as they are just too busy building and selling systems.
I myself don't even check in here much more because... well,... flying, work, and flying FOR work!! the best of both worlds.

To set the record straight, SDS started copying the EFII system in 2015.
SDS never had much penetration into the experimental market - only a few customer designed installations. EFII made the first full, safe kit for Lycoming engines in 2007 and has more than 400 installations to date. The weakest part of the EFII kit was always the 1990s technology SDS ECU that was included.

Now that EFII is introducing the new System32 control electronics, the weak part of their kit is gone - thank god!

The new parts are state of the art and very impressive. Robert Paisley has been designing engine electronics since the 1980s. I'm sure a lot of people will be upgrading as quickly as they can to System32.

I myself will be upgrading, but only because I want the latest and greatest. Ultimately it won't change how my plane flies or how the engine runs. I'll just have to decide do I want to take a full weekend or so from flying to do any work... (honestly, once you start flying, the LAST thing you ever want to do is more work)
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Last edited by Mike S : 03-14-2018 at 08:30 AM. Reason: remove rude/insulting comments about another member
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