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I'll show you mine, SDS fuel map

jclemens

Active Member
SDS fuel map

I would love to see your SDS fuel map to compare with mine. If you are running an SDS system and could post your ECU settings sheet along with any details of the engine that might be pertinent that would be great!

Here is mine:

IO-360 parallel valve
10:1 compression
Lycon Cam
Sky Dynamics intake/sump
C/S MT 3 blade
 

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O-360 SDS map

Mine is a O360A4A fixed pitch in a 6A
Set up for basically 12 to 13:1 in normal flight, slightly richer in climb out, & 16:1 in LOP operation, max 33 BTDC when appropriate - hands off.
 

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Mine is a O360A4A fixed pitch in a 6A
Set up for basically 12 to 13:1 in normal flight, slightly richer in climb out, & 16:1 in LOP operation, max 33 BTDC when appropriate - hands off.

Ralph, you're running strictly 100LL, correct?
 
11:1 preferable during climb out, but no issues with the 12 to 13:1 during normal or high power cruise.
These settings have been OK for our late summer/fall/winter (in Canada) so far but you might need to map a bit richer if you fly in warm climates. & there is the Knob (which I haven't had to resort to using) if really needed.

I suggest you view Ross's second video on my plane, 'RV-6A Project Part 2', & watch the second half where he reviews the graphical data output and explains how the map is reacting. Note the AFR trend doesn't change much with engine cruise power changes, but does richen up in climb power settings & abruptly changes with the LOP settings. We acknowledge there was a sensor issue causing the AFR varience (which has since been fixed) but look at the general AFR trend with varying power settings.

Also, note this is a fixed prop map. A C/S map may reflect slightly different values in the 2300 - 2500 rpm range due to your ability to load up the engine with more MAP.
 
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Ross's base installed map is a good starting point, I strayed away from it initially thinking I had a better idea, but after many renditions and gaining more understanding of how all those charts play together, the (near) final map has evolved.
The trick is make SMALL value changes to the map, in only ONE chart at a time.
Test & re-evaluate before changing anything else...

Doesn't hurt to have Ross just down the street though, but we visit & help each other out all the time anyway.
 
I have never been able to get my 02 sensor to work properly (a recent conversation with Dave Anders has shed some light, however), so I've only modified the map (using EGT) to incorporate the LOP cut and my ignition map from years ago. The basic map is as delivered from SDS and aside from some extreme edge cases at start (25 degrees F, no pre heat) and a slightly ragged transition to flight idle on downwind, the ops has been flawless.
 
Have you guys got the SDS Dash (data downloader) from Ross? Invaluable for tuning for the right AFR ranges.
What ever O2 sensor unit you have installed, be sure it's data is uploading to the SDS module. It doesn't directly affect the mapping parameters, but is downloadable to the SDS Dash on your laptop. You want to see the AFR trend reactions to the various sensor inputs as they happen.

Tuning by EGT/CHT is like going target shooting with the wrong pair of glasses on.

Toobuilder - the SDS Dash graphical presentation would highlight the map parameter that's causing that ragged transition real quick.
 
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Ralph - I'd very much like the 02 to work but to date the best I can get is a reading at idle - as soon as I advance the throttle to TO power the display either shows a fault, or zeros. I have the bung at 11:00 oclock, its well upstream of the end of the pipe, and several inches downstream of the 3-1 merge. I have tried 2 different Bosch sensors and 2 different controllers (both 14 point 7).

Dave Anders suggests that he had the same issues at first and it was traced to a leaky slip joint upstream of the bung.

I do have the data logger but I have yet to plug it in, figuring that the O2 is not tracking there either. Can it show a fault on the SDS display but still log properly in the ECU?
 
Michael- try in the setup prompts to change the O2 type, maybe another choice may play nicer with your O2 sensor pkg. Another possibility might be in the advance settings where you can set the 0 - 5 volt scale and afr range. Ross talked about this in the SDS 2020 thread (can't find it right now).

I originally had an AEM O2 sensor pkg and found it would show a display error on the SDS controller sporadically. I think I was getting AFR spikes beyond the 9:1 to 19:1 scale (probably caused by my Acc-pump Lo & Hi settings) that would result in display errors. I can go to my #1 display screen on the SDS and than touch the +10 button to reset or clear the error messages.
Even with the error messages, I could still export the O2 data to my laptop running the SDS Dash datalogger. I am now using the Bellenger O2 pkg and rely on it's AFR display for visual monitoring, but still wire it's output to the SDS so I can us it's data for the SDS Dash datalogger.

Jclemens- I prefer the AFR information going to the SDS & SDS Dash data logger because it pairs up the specific sensor inputs that calculate the fuel map all together, you get a perfect time line match with the O2 sensor and see what fuel map setting (AT, TPS, RPM, MAP, TEMP) is causing a jump in the AFR at that specific moment.
Your map seems to place much more emphasis on MAP values & changes compared to my setup. My fuel map places more emphasis on RPM/FUEL as a base and have MAP (& the other sensors) react in a less dramatic way, less AFR swing.
I looked over your datalog file and really couldn't pull any useful conclusions as there were climbs, descents, rpm & assumed power changes during the flight.
My procedure for a fuel mapping test flight would be to climb out to a specific altitude and set a specific rpm/power setting, say 2200, hold it there for a couple minutes, change rpm to 2300, again hold for a couple minutes & work up the rpm scale, all flying consistently so flight parameters don't change. Note I have fixed pitch so test process is simpler than would be useful with a C/A prop setup. Than I'd repeat whole process at a couple thousand ft higher. I would also set up climbs a varying speeds (different engine loading) & hold constant climb to get data from those flight conditions. The data log file will show each test segment and how the sensors are affecting the fuel map at that point and it's resulting AFR.
You could set rpm and move up the scale of throttle/map, holding for a few minutes each. Than up the rpm by 100 and repeat the throttle/map scale, repeat these sequences up as high as you want. This would give you a clear picture how your fuel map settings are working as they affect the AFR at each point.
Sorry for being long winded on this, just trying to possibly save you some of the folly I went thru.
 
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I had poor results with the 14point7 controller, the Ballenger unit has been flawless so far. My AFR data is going to the SDS as well as the G3X. I can data log it with SDS Dash and have done so, but the information in the G3x data log contains all the info I need and more. The only things I can't see in it are AT, TPS, and Ignition. None of those are things that I am looking to change. I use the same procedure when the test flight card has "collect AFR data" on it, the flight you looked at was stability tests (still in phase one). Here is a flight that has an RPM/AFR data collection portion:

https://apps.savvyaviation.com/flights/4692257/8ef24cbe-54a1-4f9b-b929-7823375a295f

My SDS map has only been modified from the one that Ross provided initially in the RPM fuel section, the start values, and the timing. The MAP values are unchanged. Right now I am very happy with the values we are currently using, the engine runs flawlessly, has great power, and temps are under control. I did read Ross's post about being able to adjust the AFR offset in the advanced setting and meant to look into that. That's the other reason I am not using SDS Dash to log, the AFR on the SDS is off from the display on the ballenger unit and my G3x matches it perfectly. Since the Ballenger unit has a calibration function and they claim to be the benchmark for accuracy I want to use this number for tuning.
 
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