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  #91  
Old 08-18-2020, 07:25 AM
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Sam Buchanan Sam Buchanan is offline
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Quote:
Originally Posted by DanH View Post
Personal opinion, but if the mission is mostly fun flying at lower altitudes, there is little value in variable advance. A Surefly set for fixed timing is a fine choice for that application. The user stills nets all the start and idle advantages, can run very, very lean when desired, and can climb at will without driving CHT to the top of the scale. It's not ultimate performance, but it is easy on the machine.
That is also my opinion based on my mission profile and experience with a fixed-timing SureFly.
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  #92  
Old 08-18-2020, 12:22 PM
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Quote:
Originally Posted by Sam Buchanan View Post
That is also my opinion based on my mission profile and experience with a fixed-timing SureFly.
Walt, Dan & Sam:
Amen, my motor is much happier since I switched my SureFly to fixed timing

RV-7A AeroSports PowerO-375 /205HP
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  #93  
Old 01-12-2022, 08:56 PM
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gmcjetpilot gmcjetpilot is offline
 
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Retard the base timing a few degrees, up to 20 Deg BTDC that will help temps....
Did you see a difference between fixed and variable?

I am assuming but pretty sure Surefly does not advance timing unless under 75%, the the advance curve is mild. You will not reach the full advanced until power is very low, Don't know what surefly is programed to, but guessing 55% power or less?
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Last edited by gmcjetpilot : 01-12-2022 at 08:58 PM.
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  #94  
Old 01-13-2022, 06:10 AM
Scott Hersha Scott Hersha is offline
 
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SureFly begins retarding the timing when below 25Ē MAP, and the variable curve is based on RPM/MAP ratio. Max advance is 38* at a very low MAP (I donít know what that is). They have done extensive detonation testing and have found no issues with their built in advance curve - which they donít publish. I got this information from a SureFly engineer last week. The certified units that go on new Lycomings are fixed timing. I donít think they are working on variable timing for certified installations, but they are working on a two SureFly installation with Lycoming. They had one at the Lycoming tent at Oshkosh last summer. Aircraft Spruce has the SIM4ís in stock right now, but SureFly has a limited number in stock, however, they do have rebuilt SIM4 & 4Pís in stock at a lower price (~$400 lower). These units are primarily returned units that had little or no run time, and in most cases, nothing wrong with them (installation error). They carry the same 2 year warranty as a new one.
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RV6/2001 built/sold 2005
RV8 Fastback/2008 built/sold 2015
RV4/bought 2016/sold/2017
RV8/2018 built/Sold(sadly)
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  #95  
Old 01-13-2022, 06:24 AM
sailvi767 sailvi767 is offline
 
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Quote:
Originally Posted by Scott Hersha View Post
SureFly begins retarding the timing when below 25” MAP, and the variable curve is based on RPM/MAP ratio. Max advance is 38* at a very low MAP (I don’t know what that is). They have done extensive detonation testing and have found no issues with their built in advance curve - which they don’t publish. I got this information from a SureFly engineer last week. The certified units that go on new Lycomings are fixed timing. I don’t think they are working on variable timing for certified installations, but they are working on a two SureFly installation with Lycoming. They had one at the Lycoming tent at Oshkosh last summer. Aircraft Spruce has the SIM4’s in stock right now, but SureFly has a limited number in stock, however, they do have rebuilt SIM4 & 4P’s in stock at a lower price (~$400 lower). These units are primarily returned units that had little or no run time, and in most cases, nothing wrong with them (installation error). They carry the same 2 year warranty as a new one.
Surefly is approved for use in the variable timing mode on a large number of certified aircraft. They are adding more all the time. The applications guide on their website shows which certified aircraft are allowed to run variable timing. All the certified aircraft I am aware of at my airport are running the variable mode. I am the outlier running 23 fixed. We had trouble with the variable mode and with our 9.5 to 1 pistons decided to go fixed.
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Last edited by sailvi767 : 01-13-2022 at 06:29 AM.
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  #96  
Old 01-13-2022, 10:09 AM
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rv6ejguy rv6ejguy is offline
 
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Quote:
Originally Posted by Scott Hersha View Post
SureFly begins retarding the timing when below 25Ē MAP, and the variable curve is based on RPM/MAP ratio. Max advance is 38* at a very low MAP (I donít know what that is).
They RETARD timing below 25"?
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Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 456.0 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
https://www.youtube.com/channel/UCiy...g2GvQfelECCGoQ


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  #97  
Old 01-13-2022, 06:28 PM
Scott Hersha Scott Hersha is offline
 
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Quote:
Originally Posted by sailvi767 View Post
Surefly is approved for use in the variable timing mode on a large number of certified aircraft. They are adding more all the time. The applications guide on their website shows which certified aircraft are allowed to run variable timing. All the certified aircraft I am aware of at my airport are running the variable mode. I am the outlier running 23 fixed. We had trouble with the variable mode and with our 9.5 to 1 pistons decided to go fixed.
Yep youíre right. Just found this out today. I have a friend that is building an RV14 with the Lycoming IO-390, with dual Lycoming EIís (SureFly) and has removed them to install a dual EFII system. I thought I might buy one of his SIMs for my RV6 build, so I called SureFly. The certified units have different firmware as designed by Lycoming. SureFly is building these units under contract for Lycoming. Lycoming specifies the settings that are internal and not adjustable by the operator. Their variable advance curve is proprietary and not the same as what you would get with a blue SureFly. These particular SIMs were set for 20* VAR - meaning a 20* standard advance with variable timing. On this unit, the max variable advance is to 28*. And you canít change any of that. Dip switch access is not available, so I couldnít change it to my 25* engine. The timing schedule, advanced or fixed, is set in the firmware. Also, SureFly doesnít own this mag, Lycoming does, so any warranty that may or may not be implied is Lycomingís responsibility. And Lycoming has a terrible track record in support of this system.
I will be buying a blue SureFly SIM from SureFly or Spruce and it comes with a 2-year warranty from time of installation - even if you buy a factory rebuilt unit, and SureFly offers very good support. This will be my second airplane with a SureFly ignition.

Ross,
I guess Iím a little backwards sometimes - yes I meant to say ADVANCE timing.
Sorry.
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RV6/2001 built/sold 2005
RV8 Fastback/2008 built/sold 2015
RV4/bought 2016/sold/2017
RV8/2018 built/Sold(sadly)
RV4/bought 2019/sold2021
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JAN2022
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  #98  
Old 01-13-2022, 07:57 PM
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DanH DanH is online now
 
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Quote:
Originally Posted by Scott Hersha View Post
I have a friend that is building an RV14 with the Lycoming IO-390, with dual Lycoming EIís (SureFly)...On this unit, the max variable advance is to 28*. And you canít change any of that.
Scott, confirm please. Your understanding is that these Lycoming-branded units supplied with the 390 have a 28 degree maximum advance?
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  #99  
Old 01-14-2022, 06:10 AM
Scott Hersha Scott Hersha is offline
 
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Dan,
No, I canít say for sure, but that is what the RV14 builder, Bruce Brielmaier told me. I assume he read it some where in the supplied paperwork that came with the engine. Iíll try to clarify when I see him next - probably today.
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RV6/2001 built/sold 2005
RV8 Fastback/2008 built/sold 2015
RV4/bought 2016/sold/2017
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JAN2022
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  #100  
Old 01-14-2022, 09:14 AM
Scott Hersha Scott Hersha is offline
 
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Quote:
Originally Posted by DanH View Post
Scott, confirm please. Your understanding is that these Lycoming-branded units supplied with the 390 have a 28 degree maximum advance?
Dan,
I just talked to Bruce about his engine. He said that he spoke with a Lycoming engine rep at Sun N Fun and was told that the max advance on the 390 with variable timing is 28*.
Incidentally, he has installed the SDS dual ignition system in itís place, not the EFII system as I said earlier.

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SPK. ADV. 20VAR - bottom row on data plate.
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RV6/2001 built/sold 2005
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