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jclemens 02-04-2021 08:50 AM

SDS fuel map
1 Attachment(s)
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

Ralph Inkster 02-04-2021 11:34 AM

O-360 SDS map
1 Attachment(s)
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.

airguy 02-04-2021 12:57 PM


Originally Posted by Ralph Inkster (Post 1500326)
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?

Ralph Inkster 02-04-2021 01:14 PM

Yep. I hate gas cans...

jclemens 02-04-2021 02:17 PM

You have any cooling issues with a 12-13 AFR?

Ralph Inkster 02-04-2021 09:11 PM

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.

jclemens 02-05-2021 07:31 AM

I have seen the vids. The map I posted is changing each flight now that I have a reliable AFR sensor. We were eating o2 sensors in single flights before. The Ballenger unit has been solid so far. I had temp issues early on, but I think we have got that under control now with a larger cooler and some cowling mods. Here is the data from the last flight:

jclemens 02-05-2021 08:21 AM

Also, no fair! How do I get Ross to tune my airplane?

Ralph Inkster 02-05-2021 08:54 AM

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.

Toobuilder 02-05-2021 10:27 AM

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.

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